GlossaryGlossary

A 3D model is an image of the building on a screen. You can turn it, change its size and select parts of it. The software makes it from the floor plan, and it is not a photo or render that does not change.

Acclimation is the change in which a plant adapts to a higher light intensity during some weeks. The plant makes more chloroplasts, thicker leaf cuticles and a higher density of enzymes. Thus it can use the higher light intensity safely.

Acclimatization (hardening) is the task to make a plantlet from tissue culture stronger. You decrease the humidity and increase the light gradually. Thus the plantlet does not die in usual air.

An action limit is a value that you set before. When a reading is on the incorrect side of this value, a specified procedure is mandatory, and you must write the corrective action. An alert limit is a weaker limit that gives only an indication.

An action threshold is a specified quantity of pests that starts a specified control procedure. For example, the quantity can be one pest that you see, or pests in more than 3% of a room.

An advisory (prescription) is an output that gives the task, the setpoint, the time limit and the result that will occur. It tells you: 'do this, by this time, or this result will occur'. It is not only an alarm.

An air embolism is an air bubble in the stem after you cut it. It stops the uptake of water. You can prevent it if you put the cuttings in the substrate quickly and keep the ends of the cuttings wet.

Air-filled porosity is the part of the pore space of a substrate that holds air immediately after the substrate drains. When the air-filled porosity increases, the water-holding capacity decreases.

An airlock (gowning cascade) is a sealed room between two spaces. Its doors cannot open at the same time. Personnel put on more protective clothing in the room before they go into a space with a higher grade.

ALCOA+ is a list of properties for data integrity. Records must be Attributable, Legible, Contemporaneous, Original and Accurate, plus Complete, Consistent, Enduring and Available.

Aliasing is an effect in data that occurs when the sampling is too slow. The slow sampling changes a fast cycle into a slow cycle that does not occur in the plant.

Alkalinity is the capacity of water to neutralize acid. The capacity comes mostly from bicarbonates, and you give the value as ppm of calcium carbonate (CaCO3). Alkalinity is not the same as a high pH reading.

Annex 11 and PI 041 give the GMP requirements for computerized systems and data integrity (access control, audit trails, validation and backups).

Apical dominance is the usual condition in which one primary top of a plant becomes higher than the side branches. Topping and LST stop apical dominance. Thus the growth of the plant is equal in all the branches.

AppDaemon is the Python software environment that operates the primary decision loop of Crop Steering, which has approximately 5900 lines, on Home Assistant.

The AppDaemon engine is the automatic controller (file master_crop_steering_app.py). It reads the sensors and the settings, selects the phase of each row, and operates the hardware sequence.

Aseptic technique is the method to keep bacteria, fungi and yeast out of your culture. It is the most important method in tissue culture.

The industry standard for dry cannabis flower gives the range of 0.55 to 0.65 aw.

An auto-tick is a check item that the system records as done automatically, when its telemetry shows that the condition is correct. Thus the person does only the items that a sensor cannot examine.

An autoflower seed is a seed with ruderalis genetics. The plant starts flowering automatically after a small number of weeks, and the photoperiod does not change this.

An auxin is a type of plant hormone that increases the growth of roots. IBA is the best auxin for cannabis.

The background drip baseline is the stable drip of the AC and the dehumidifier that the system finds at night. Then the system can subtract it from the total drain readings.

The baseline (trajectory) is the learned envelope for a specified cultivar, growth stage and photoperiod phase. The system calculates it from the data of your previous crops.

A batch (lot) is one specified production run with one ID. The ID stays with the material in each transfer.

A batch (lot) record is the document that records all the materials, tasks, personnel, equipment, results and disposition for one batch (FRM-MF-004). REG-CU-001 holds these records together.

Batch release is the controlled decision that a completed batch is safe and agrees with the specification. Test results and records give the data for the decision. The batch can go to a customer only after the decision.

Bicarbonate is the primary compound in the water that causes alkalinity. It neutralizes the acid that you add, and thus the pH increases again.

Bioaerosol is a group of particles in the air that contain organisms. Examples are small pieces of skin with bacteria, fungal spores, and drops of liquid from a person who speaks or from a toilet flush.

A biocontrol, or beneficial organism, is an organism that you release to decrease the quantity of a pest. It can be a predator mite, a parasitoid wasp, or a microbe such as a fungus or a bacterium.

Biological control (biocontrol) is the procedure in which you release predators, which are insects or mites that eat pests. The predators do not cause damage to the plant. When no prey is available, the number of predators decreases.

Bleaching is a change of color in which the tissue becomes white or almost white. It occurs usually at the tips in the top of the canopy. Stress from light and oxidation causes it, and it is the result of photoinhibition that you can see.

The blocked-dripper guard is a fail-safe. It stops the irrigation of a row for approximately 2 hours after too many emergency shots fail (default 4 in 30 min). Each row has an on/off switch for it.

The boundary layer is the thin layer of air that does not move, on each leaf surface. CO2 that goes in, and water vapor and heat that go out, must diffuse slowly across the layer. Thus the layer sets a limit on the rate of work of the leaf. Air that moves (approximately 0.3 to 1.0 m/s at the canopy) makes the layer thinner. In a dense canopy, a layer in air that does not move sets a limit of CO2 that no room sensor shows.

Bti and Btk are types of the soil bacterium Bacillus thuringiensis. Bti (israelensis) kills the larvae of fungus gnats, and Btk (kurstaki) kills caterpillars. The two types kill the pest only when the pest eats them.

Bucking is the procedure in which you cut the buds from the stem. You do it after trimming.

Bud rot (botrytis) is a gray mold that causes rot in buds with a high density, when the humidity is high. It is a primary risk in the last stage of flowering. Because of this risk, growers decrease the humidity.

Bud set is the time, approximately in weeks 3 to 4, when the pistils make small buds with a clear shape that become larger. Before this time, the pistils are at different positions.

Buffering is the resistance of a substrate to a change of pH. Soil has high buffering, and coco and hydroponics have almost no buffering. Thus you must control the pH of coco and hydroponics with more precision.

A buffer solution is a liquid with a pH that you know accurately, for example 4.0 or 7.0. You use it to calibrate a pH pen.

Buffering is the capacity of a substrate to absorb errors in the pH or in the strength of the nutrients. Thus the environment of the roots is more stable.

Buffering capacity is the resistance of a substrate or of water to a change of pH. High buffering gives a small change of pH (soil). Low buffering gives a fast change of pH (coco, hydroponics).

Build back is the procedure in which you add minerals again to RO water or rainwater that has almost no minerals. The procedure is necessary because the plant must continue to get calcium, magnesium and some buffer. You usually add a CalMag supplement and the primary nutrients.

Bulk EC is the electrical conductivity of the mixture of the wet media (solids, water and air). The probe measures it directly in the range of 0-20000 microS/cm.

Bulking is the middle phase of flowering (approximately weeks 5 to 7). In this phase, the mass of the buds increases at the highest rate.

Burping is a short opening of a sealed container during curing. The opening lets moist air go out of the container and lets new air go into it.

C1D1 (Class 1 Division 1) is a classification for areas where flammable solvent vapor can be in the air. It is for electrical equipment and rooms. These areas must have explosion-proof equipment and gas detection.

Cal-mag is a supplement of calcium and magnesium. It is necessary when you use coco, to prevent the deficiency that the CEC of the coco causes.

Calibration is the adjustment of the reading of a sensor, to make it agree with the correct value for the substrate that you use. Without calibration, the percentage on the screen can be incorrect.

A calm dashboard is a screen that shows exceptions. Usually the screen gives no information. It tells you only when there is important information.

CalMag is a supplement of calcium and magnesium, frequently with iron. You add it to water that has a small quantity of minerals, such as RO water, rainwater or very soft tap water. It prevents a deficiency of calcium and magnesium.

The Calvin cycle is the half of photosynthesis that uses CO2. It changes the light energy that the plant absorbs into sugar. If the concentration of CO2 is too low, this stage cannot operate at the same rate as the light reactions.

A calyx is one small part of the flower, in the shape of a drop. Many calyxes together make a bud.

Cannabis ruderalis is a strong subspecies of cannabis. Its genetics give autoflowers the automatic flowering that the photoperiod does not control.

CAPA (Corrective And Preventive Action) is the standard procedure to repair a problem and to make sure that it does not occur again. It is one of the primary procedures of GMP.

CAPA (Corrective and Preventive Action) is a procedure that starts from the root cause. Corrective action repairs a problem that occurred. Preventive action makes sure that a problem does not occur, or does not occur again.

A capacitance sensor is a probe that measures the quantity of water in the substrate. It senses the electrical 'permittivity' of the substrate. Water changes the permittivity much more than soil or air does.

Carbonate and bicarbonate (CO3 and HCO3) are the compounds in solution that cause alkalinity. They neutralize the acid that you add. If the quantity is too large, they can cause lockout of calcium and magnesium.

A CCP (Critical Control Point) is a step in an operation, with a measured limit that prevents a specified hazard. It is a term from HACCP for control during the operation.

CEC (cation exchange capacity) shows how strongly a substrate holds cations, which are nutrient ions with a positive electric charge (in meq/100g). A high CEC gives more buffering of errors in the feed.

The standard procedure for each change that can change the quality of the product or the validated state is change control. In this procedure, you examine the change, give approval for it and then make it.

Channeling (preferential flow) is water that flows straight down through the substrate. It does not touch the roots, and frequently it does not touch the sensor.

Chloramine is a disinfectant of chlorine and ammonia that is more stable than chlorine. It does not go out of the water as a gas when you keep the water in a container. To remove it, you must use a catalytic carbon filter or reverse osmosis.

Chlorine is a disinfectant that suppliers frequently add to tap water. It moves from the water into the air as a gas in approximately 24 hours if you keep the water in a container with aeration. Chlorine can cause damage to the tips of the roots and to beneficial microbes at low concentrations.

A chloroplast is the structure in a cell that does photosynthesis. During acclimation, plants make more chloroplasts. Thus they can use a higher light intensity.

Chlorosis is the condition in which leaf tissue becomes yellow because the quantity of green chlorophyll decreases.

A cleanroom grade shows the maximum number of airborne particles that a room can have. To control the contamination of the product, you use a grade with a smaller maximum number of particles, and you use gowning.

A cleanroom grade shows how clean the air of a room is. In CNC, the air has no control, and no other grade has air as clean as Grade A. The grades agree with the ISO 14644 classes (D=ISO 8, C=ISO 7, A=ISO 5).

A clone is a copy of a plant that has the same genes as the plant. You can make a clone from a cutting or with tissue culture.

A closed loop is a control system in which the result goes back to cause the next step. The steps are: measure, select, adjust, and then measure the effect of the adjustment. The system does these steps again, continuously.

In a gated closed loop, the system does automatically only the tasks that have a low risk and a specified license. A person must give approval for each task that is permanent or has a high cost.

Closed-loop control is a system that measures a result, compares the result with the value that you want, and makes adjustments automatically. A thermostat is a typical example.

CO2 supplementation is a procedure in which you add carbon dioxide to the air. The concentration of carbon dioxide is then more than the usual value in the air (approximately 400 to 600 ppm). It agrees with a high light intensity, and it is necessary to prevent bleaching at intensities such as 1200 or 1500 µmol/m²/s.

A CoA (Certificate of Analysis) is the document that gives a list of the test results of a batch and compares them with the specification. You supply it at release.

Coco coir is a substrate of coconut husk that you use as an alternative to soil. Water flows out of it quickly, and it changes quickly when you apply water.

The coefficient of variation (CV) shows how large the variation is, in relation to the average. For a batch of plants, the CV measures the noise (the differences between the plants) in your crop.

A cola is a large group of buds with a high density on a primary stem. The cola is usually the flower at the top of the plant, and it has the best growth.

Common-cause variation is the usual small random change of a stable operation. It stays in the control limits. You must not adjust the operation for this variation.

Common-cause variation is the usual small random change, and you do not adjust the operation for it. Special-cause variation is an unusual change, for example a point that is out of a limit or a sequence of points that is not random. An investigation is necessary for it.

Confidence is the value that the system gives to show how accurate its estimate is at this time. When the confidence is high, the system can apply water. When the confidence is low, the system must be careful.

Control limits are limits that you calculate from the data that you recorded for the operation (typically the mean ± 3 standard deviations). They divide the usual variation from the unusual variation.

Control limits are limits around the usual variation, and you calculate them with statistics. A reading in the limits is only noise, and a reading out of the limits is a signal for a correction. SPC is the short name of 'statistical process control'.

Cotyledons, or seed leaves, are the two rounded leaves of the embryo that you see first. They contain nutrients and supply them to the seedling.

A coupled system is a system in which a change to one control changes some other controls at the same time. Thus no lever operates independently.

Crop steering is a method to cause a plant to make more vegetative growth (leaves) or more generative growth (flowers and fruit). You control the irrigation, the climate and the light.

Crop Steering AI (CS) is an irrigation system with 4 phases. It uses sensor data, and it has control for each zone, EC logic and ML prediction. It is the irrigation controller that operates at this time.

Cross-contamination is the movement of contamination from a dirty area or item to a clean area or item. For example, a person goes from the flower area back to the propagation area and does not put on a gown again.

Culling is the procedure in which you divide the clones into groups before transplant. You remove the clones that are weak or do not have roots. The groups are keepers, rejects and kills.

Curing is the procedure in which a completed batch becomes stable, with the same water activity in all the flower. During curing, you keep the terpenes and prevent mold.

A cutting is a shoot that you cut from a plant. It makes roots and becomes a clone. The terms cutting and clone are interchangeable.

A cytokinin is a type of plant hormone that increases the growth of shoots and buds. The examples are meta-topolin, BAP and TDZ.

Damping-off is a fungal disease (Pythium, Fusarium, Rhizoctonia). It causes rot in the seedling at the level of the soil, and it usually kills the seedling.

A dead-band is the tolerance range in which a controller does not make a correction. If the dead-band is too small, the equipment makes too many adjustments (hunting).

Defanning (defoliation) is the removal of selected large fan leaves. It opens the canopy. Thus light goes into the canopy and air flows through it.

A deficiency is the condition in which the plant does not get a sufficient quantity of a nutrient. The plant has less color, becomes yellow, and its growth is slow.

Defoliation is the removal of selected leaves. Thus more light and more air go into the canopy.

The dehumidification load is the quantity of water that a room must remove from the air each day to keep its humidity target. The transpiration of the canopy sets the load, and at a high light intensity the load is frequently the limit of the yield. The unit is liters or US pints each day (1 liter is approximately 2.1 pints), and a dense flowering canopy can transpire some liters for each square meter each day.

A deviation is each difference from the approved procedure in the documents. You must record it and do an investigation.

A digital twin is a 3D model connected to the data of sensors in the facility. Thus it shows the temperature, the humidity and the equipment status at this time.

Dilution is the procedure in which you mix a material equally in a large volume of water. Thus the concentration is low. This low concentration makes it safe to add Part B after Part A.

Dissolved oxygen (DO) is the quantity of oxygen in solution in water, and the roots must have it. DO decreases when the temperature of the water increases, from approximately 5 to 6 ppm at 20 °C to 3 to 4 ppm at 26 °C. A low DO increases the risk of root disease.

DLI (daily light integral) is the total quantity of light that a plant receives and can use in one day, in mol/m²/day. You calculate DLI from the light intensity (PPFD) and the hours of light. Thus two different intensities can give the same DLI with different photoperiods.

DLI (daily light integral) is the total number of PAR photons that a surface receives in one day, in moles for each square meter (mol/m2/day). DLI = PPFD x seconds of light in each day / 1,000,000. It is the dose that has the largest effect on the yield.

A dome is a transparent plastic lid for humidity. You put it on a clone tray to keep moisture around the cuttings that do not have roots.

A draw call is one instruction to the graphics card to show an object. When the number of draw calls is smaller, the model is faster (keep the number less than approximately 300).

A drench is a treatment that you apply to the substrate and the root zone, and not to the foliage.

Drift is a slow sensor error that is always in the same direction, and it shows a trend that does not occur in the plant. It is the dangerous type of noise. Only calibration and a check with other data can remove it.

The dry-to-wet ratio is the last dry weight as a fraction of the initial wet weight. It is approximately 10% in the source data.

Dryback is the quantity by which the moisture in the root zone decreases between irrigations. A grower sets the dryback to cause generative growth or vegetative growth in the plant.

Dryback % is the size of a dryback, in percentage points of water content. It is the peak of each day minus the next trough. For example, 78% to 58% is a dryback of 20 points.

DUL (drained upper limit), or container capacity, is the quantity of water that a container holds after free drainage stops. It is a value that you find for each pot, and it is not a constant value for the substrate. It changes slowly when the roots become larger.

DWC (deep water culture) is hydroponics in which the roots hang in nutrient water with oxygen, and there is no solid medium. An air pump supplies the oxygen.

EC is electrical conductivity. It shows the strength of the nutrients in the feed water, in mS/cm.

EC gives an estimate of the quantity of fertilizer salt that is in solution in the root zone. When the EC is higher, the feed is stronger.

The EC ratio is the measured EC divided by the target EC. When the ratio is more than 1, the salt strength is too high (apply more water to dilute). When the ratio is less than 1, the salt strength is too weak (apply less water).

Efficacy is the number of PAR photons that a fixture makes for each joule of electricity (umol/J). It is the primary number for the efficiency when you compare lights. Good LEDs have approximately 2.7 to 3.0 umol/J, HPS lights have approximately 1.7 to 1.9, and CMH lights have approximately 1.3 to 1.9.

EM (Environmental Monitoring) is the procedure to get samples of non-viable particles, viable air, surfaces and personnel. You compare the results with the alert limits and the action limits.

The embryo is the very small plant in the seed. It contains a root, two cotyledons and a shoot.

An endophyte is a microbe that is in the tissue of a plant that looks in good condition. It is the contaminant that you cannot easily remove in tissue culture, because bleach on the surface cannot touch it.

Entomopathogenic nematodes are very small worms, for example Steinernema feltiae. You apply them as a drench to the substrate. They are parasites of fungus gnat larvae, and they kill the larvae.

ESPHome is the firmware platform that operates the hardware sensors and some switches. It sends the data to Home Assistant.

EWMA is the exponentially-weighted moving average. It is a rolling average that gives more weight to the newest readings. Thus it has less lag for the same smoothing.

Exclusion is the procedure in which you control the persons and the items that go into a room with pests. It stops pests that move from one room to a different room.

An explant is a small piece of a plant. You cut it from the plant and put it in the culture vessel to start a new culture.

To extrude is to extend a flat 2D shape (for example, the shape of a floor) up, to give it thickness or height.

In a fail-safe read, the engine cannot find the condition of the primary arm switch. The engine then uses the condition OFF and does not apply a shot. Thus a condition that is not synchronized cannot cause the engine to operate without data.

Fan leaves are the large leaves that have a small number of trichomes. You remove them by hand at the start of trimming.

Far-red is light of approximately 700 to 750 nm, immediately after the PAR range. Phytochrome senses far-red light, and far-red light can make the plant sense the start of the night more quickly. Far-red light causes some stretch of the stem, and high doses of it can decrease the density of the buds.

In feedback, a system uses the measured result of an operation to select the next operation. Feedback is the primary part of each closed-loop system, which makes corrections automatically.

A feminized seed is a seed that a breeder makes to give almost only female plants. Thus it is not necessary to identify and remove male plants.

Field capacity is the maximum VWC that the medium can hold before water flows out. The default maximum is 70%.

The substrate EC is the concentration of salt in the substrate of the root zone. The Athena guide gives targets for each stage, for example 3 to 5 in the vegetative stage. You use the mixed feed to increase the substrate EC to these targets.

FIM is a topping in which you cut most of the top tip but not all of it. FIM can make some new tops. A topping that removes all the tip makes only two new tops.

The fit-out is the equipment and furniture in the bare shell of the building: benches, lights, dehumidifiers, tanks and racks.

The flip is the change of the grow light timer to 12 hours on and 12 hours off. The change causes flowering in photoperiod plants.

A floor plan is a flat drawing from an architect. It shows the walls, doors and rooms from above, usually with dimensions in millimeters.

Florigen is a protein that moves in the plant and is the flowering signal. The leaves make it when the nights are sufficiently long. It moves to the growth tips, and it causes them to make buds and not leaves.

A flush is the procedure in which you apply water that flows through the substrate and removes the salts that collect. The water has the correct pH, and it has no fertilizer or a small quantity of fertilizer. Thus the root zone is in its initial condition again.

A foliar spray is a liquid treatment that you apply to the leaves and the stems, and not to the root zone.

A fomite is an object that holds microbes and moves them to a different object. Examples are a phone, a pen, a tool or a handle. Hands move contamination from fomites to the crop.

An FOV cone is a transparent shape that shows the area in the field of view of a camera. The floor out of all the cones is a possible blind spot.

Frass is waste from insects and small pieces of material. During scouting, you can see frass as one of the first signs of pests.

The full pot (DUL, drained upper limit) is the maximum quantity of water that a pot can hold after drainage.

GACP (Good Agricultural and Collection Practice) is the standard for cultivation and drying, before the GMP facility. It supplies biomass that agrees with GMP to the facility.

GACP (Good Agricultural and Collection Practice) is the standard for the cultivation and collection of the starting material of medicinal cannabis. In this standard, the material is a plant crop before it becomes a medicine.

GDP (Good Documentation Practice) is a group of procedures to make and to correct records. You make a record at the time of the task, and you cannot erase it. A correction is one line through the error, with initials, a date and a cause, and the initial entry stays easy to read.

Genealogy (traceability) is the record that connects each completed unit to its source lots, operators, equipment and conditions, forward and back. It makes possible a recall of specified lots only.

A generalist predator eats many types of pest and also eats pollen. It stays in the crop when there is no prey. A specialist predator eats one type of pest quickly, but its number decreases when there is no prey of that type.

The two growth modes of a plant are vegetative growth (leaves, stems and size) and generative growth (flowers, fruit and density). Crop steering changes the balance between the two modes.

Germination is a sequence in which a seed in dormancy absorbs water and becomes active. Then the seed extends its first root and its first shoot.

The germination rate is the percentage of the seeds in a batch that germinate.

glTF is a standard 3D file format. You use it to import models with much detail, which you make in tools (for example Blender), and to export the building.

GMP is a quality system of procedures and records. It makes sure that a manufacturer makes products safely, with the same result each time, and with records that let you trace each product.

Gowning is the procedure to put on protective clothing, and de-gowning is the procedure to remove it. You do the two procedures in a specified sequence at the clean/dirty line, and thus contamination does not go across it. You put on the gown from the top to the bottom, and you remove it in the opposite sequence, with the dirtiest item first.

Grams for each liter (g/L) is the unit of dose for nutrient powders. To find the grams to weigh, multiply the g/L on the label by the volume of the tank. For example, multiply by 50 for a tank of 50 L.

Hardening off is the procedure in which you open the vents gradually and remove the dome. Thus the clones with roots adapt to drier room air before transplant.

Hardness is the quantity of calcium and magnesium in solution in water. You give it in ppm CaCO3 or in grains for each gallon (1 GPG is 17.1 mg/L). Soft water has less than approximately 1 GPG, and very hard water has more than approximately 10.5 GPG.

Hermaphroditism is the condition in which a female plant in stress makes male parts. The pollen from the male parts pollinates the plant, and the buds then have seeds. A frequent cause is a light leak in the period of darkness.

The hierarchy of controls is the sequence of steps that the regulations give for the control of risk. The steps are: remove the risk, replace it, isolate it, use engineering controls, use administrative controls, and last, use PPE.

The Hilhorst model is a method from the year 2000. It gives an estimate of the pore-water EC from the bulk EC, the VWC and the temperature. You can use it, but its sensitivity is approximately +/-20%, and it is not correct when the VWC is less than 0.10 m3/m3.

Home Assistant is open-source software, with no cost, for home automation. It operates the dashboards, automations and integrations that are in this paper.

Honeydew is tacky waste with sugar from aphids and whitefly. It is on the leaves, and black sooty mold occurs on it.

Hop Latent Viroid (HpLVd) is a very small loop of RNA that is smaller than a virus. It causes 'dudding' in cannabis. Plants with dudding stay small and make smaller buds, and they contain much smaller quantities of cannabinoids and terpenes.

A humidity dome is a transparent lid that you put above seedlings. It keeps the moisture near the plants and keeps the humidity high while the roots are very small.

Hunting is an oscillation in a feedback loop. The loop makes corrections that are too large, in one direction and then in the other direction, and it does not become stable. The cause is frequently noise in the input or a tuning that is too sensitive.

Hydroponics is a method in which the roots are in a nutrient solution, or in an inert medium that receives it, and not in soil. The pH of the solution must have a value that is acid but near neutral. You must control the pH with precision.

Hyperhydricity (vitrification) is a problem of tissue culture. A culture with this problem makes glassy shoots that contain too much water and are larger than usual. The shoots make roots badly, do not acclimatize correctly, and usually die when you transplant them.

ICH Q9 and ICH Q10 are international harmonization guidelines. Q9 is for Quality Risk Management and Q10 is for the Pharmaceutical Quality System.

Imbibition is the first step of germination. In this step, the seed absorbs water and becomes larger.

An immobile nutrient is a nutrient that stays where the plant first puts it, and the plant cannot move it to a different position. The immobile nutrients are Ca, S, Fe, Mn, Zn, B, Cu and Mo. As a result, the deficiency shows first on the new growth at the top of the plant.

An implementation intention is an if-then instruction that attaches a task to a specified time and location. For example, at lights-on the AM technician does X. It makes the person do the task 2 to 3 times more frequently.

In vitro is a Latin term for 'in glass'. It is the term for all that occurs in the culture vessel without microbes. The opposite term is ex vitro, which is for all that occurs out of the vessel.

Indexing is a laboratory test of a plant, for example with RT-qPCR, to make sure that the plant has no specified disease. The test shows that the plant is clean.

An inert medium is a substrate, such as rockwool, that does not contain nutrients. Thus the plant gets only the nutrients that you apply in the feed.

The inference layer is the part of the system that calculates estimates of values that you cannot measure directly (plant stress, transpiration and vigor). It uses values that you can measure.

Instancing is the method to show many objects that are the same, for example 210 plants, in one batch and not one at a time. It is the primary method to keep the model fast.

Integrated Pest Management (IPM) is a loop of tasks that you do again and again. You examine the pests, you make a decision, and you control the pests. You use the weakest method that is sufficient, and you use a stronger method only when it is necessary.

An internode is the length of bare stem between two nodes.

Interveinal chlorosis is chlorosis between the veins of the leaf. The veins stay green. You see this condition with problems of magnesium, iron and manganese.

The inverse-square law is a relation in which the light intensity decreases with the square of the distance. When the gap between the fixture and the canopy becomes two times larger, the PPFD decreases by approximately 75%. Thus the hanging height is a control of the intensity with large steps.

IPM (integrated pest management) is a method with layers: you prevent pests, monitor the crop, use biological control and apply treatments for specified pests. IPM does not use a spray at regular intervals. This paper identifies the pests, and the IPM SOP is the procedure for decisions.

ISO 14644 is the international standard that gives classes of cleanrooms. A class is the maximum permitted number of airborne particles in each cubic meter.

A JSON file (data file) is a list of facts that a person can read (room names, sizes and positions). The code reads it to make the model.

KCl storage solution is a solution of potassium chloride that keeps the tip of a pH probe wet. If you keep the probe dry or in water without KCl, the probe has permanent damage.

The color temperature, in kelvin (K), is a value that shows the mixture of colors of a white LED. A higher value (4000 to 6500 K) gives more blue and is for the vegetative stage. A lower value (3000 to 3500 K) gives more red and is for the flowering stage.

A killer item is a check that is easy to ignore and dangerous if you do not do it. For example, it can be the dehumidification at lights-off or a dosing pump with no irrigation timeout. A checklist must make this small number of items mandatory.

Larf is a type of flower that is small, has a low density and is not at maturity. It occurs at the bud sites at the bottom of the plant, in shade. It has a low value, and lollipopping removes it.

The latent heat load is the heat in water vapor, and the dehumidifier removes it when the vapor condenses to liquid. Each liter of water that the canopy transpires becomes latent load, and thus a bright room must have a large capacity of dehumidification. The latent load is different from the sensible heat load (dry heat), and at a high light intensity it is frequently the larger of the two.

A leading indicator is a sign that occurs before the damage, and it tells you about the problem. A lagging indicator is a symptom that shows that the damage occurred.

A learned envelope is the range of values that shows a plant in good condition, for the cultivar, the growth stage and the photoperiod. The system uses it as an alternative to one constant threshold.

A lever (actuator) is each control that you can change in the room. The examples are the light intensity, the cooling setpoint, the irrigation shot and the dose of CO2. The paper counts eleven primary groups of levers.

The life cycle (generation time) is the time from the egg stage to the egg-laying adult. In warm dry rooms, this time is less than one week for spider mites. As a result, infestations increase very quickly.

Light saturation is the condition in which a plant cannot use more light, because CO2, water, nutrients, temperature or genetics is the limiting factor. Then more light intensity adds cost and stress, and it does not add yield.

Light stress (bleaching) is damage from too much light intensity. You see the damage as white or yellow bud tips directly below the fixture, leaves with edges that bend up, and less color. The correction is to decrease the intensity of the light or to lift the fixture, and not to apply more feed.

The limiting factor is the one input with the smallest supply compared with the quantity that the plant must have. Only this input sets the growth rate: more of this input increases the growth, and more of a different input gives no change. In a grow room, the weakest support system sets the limit of the yield (usually dehumidification, cooling or CO2), and not the brightest light that the fixtures can make.

Living soil (ROLS) is an organic soil bed with a large quantity of microbes (recycled organic living soil). The soil has buffering for the pH and supplies nutrients to the plants through its biology. You apply only water, and you can use the soil again and again.

Lockout is the condition in which nutrients are chemically not available to the plant. Here, a precipitate causes it when Part A and Part B mix at a high concentration.

Lollipopping is the procedure in which you remove the small branches, the nodes and the leaves from the bottom third of the plant (approximately the bottom 10 to 18 inches). Thus the energy goes to the top buds, and the plant has the shape of a lollipop.

A loupe or scope is a magnifier for inspection. A hand loupe of 30x finds spider mites. You must use a magnification of 60 to 100x to find russet mites and broad mites.

Low-stress training (LST) is the procedure in which you bend the branches down carefully and attach them in this position. The procedure makes the canopy flat, and you do not cut the plant. The stress is low and there is no recovery time.

MACO (Maximum Allowable Carryover) is the residue limit that you calculate. You use it as the acceptance criterion in cleaning validation.

A macronutrient is an element that a plant must absorb in large quantities. The macronutrients are nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S).

Management review is the review of the performance and the effectiveness of the quality system, by senior management. The review occurs at regular intervals, a minimum of one time each year.

A manual override is a total lockout for each zone. When it is ON, the zone gets no water. The lockout stops automatic irrigation, emergency irrigation and a manual trigger.

Mass flow is the primary movement of nutrients in solution to the root surface, with the water that the plant uses when it transpires. Faster transpiration moves more water and more nutrients, and thus the EC of the feed and the light intensity must increase together. If the feed is not sufficient for a bright canopy, the plants have less color.

The Master Document Register (REG-QM-001) is the primary index. It gives a list of all the controlled documents, each with its version at this time, its document owner and its review status.

A median filter uses the middle value of the last N readings. It is very good for the removal of a spike in one reading. It does not change a step change that occurs in the plant.

A medium is the material that holds a culture and gives nutrients to it. It is a gel of mineral salts, sugar, vitamins and optional hormones. A gelling agent makes the gel solid.

A meristem is a dome of new cells that divide continuously at the tip of each shoot. No other tissue on the plant is as clean as the meristem, because it is too new to contain most diseases.

A micronutrient is an element that a plant must absorb only in very small quantities. The micronutrients are iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B) and molybdenum (Mo).

Micropropagation is a method that uses tissue culture to make many copies of one plant. All the copies have the same genes.

Mineral salts are the dry crystals of a nutrient powder, as the supplier sends it. They must dissolve in water before a plant can absorb them.

A mobile nutrient is a nutrient that the plant can move from the old leaves to the new growth when the supply is not sufficient. The mobile nutrients are N, P, K and Mg. As a result, the deficiency of a mobile nutrient shows first on the old leaves at the bottom of the plant.

Moisture content is the percentage of the weight of the flower that is water. You use it to measure the yield, and not the safety.

A mother plant is a stock plant in good condition. You keep it in vegetative growth, and you remove cuttings or explants from it.

A moving average (rolling average) is the average of the last N readings. You calculate it again when you get each new reading. It decreases random variation, but it adds a small lag.

The MQS (Minimum Quality Standard) is the quality standard for products of medicinal cannabis in the NZ Misuse of Drugs (Medicinal Cannabis) Regulations 2019.

A named condition is a short diagnosis that a person can read (for example, 'salt accumulation pattern'). It has a confidence value and an evidence chain. It replaces a large quantity of numbers.

Necrosis is the condition in which leaf tissue dies. The tissue becomes brown and dry, and it breaks easily. It occurs frequently at the tips or the edges of the leaves.

A node is the point on a stem where a leaf and a bud attach to the stem. A nodal segment is a short piece of stem that contains one bud.

Noise is a random change in a measurement that does not show a change in the plant. The examples are a spike in one reading, jitter of high frequency, and transients from doors, the movement of personnel and irrigation events.

A nutrient (essential element) is one of the chemical elements that a plant must absorb for correct growth. The primary nutrients for cannabis are N, P, K, Ca, Mg and S. The plant must also absorb trace micronutrients such as iron and zinc.

Nutrient antagonism is the condition in which too much of one element stops the uptake of a different element. For example, too much potassium decreases the uptake of calcium and magnesium.

Nutrient burn is the condition in which the tips and the edges of the leaves become brown. It occurs when you apply a solution that is too strong (too much salt). It is one type of toxicity.

Nutrient lockout is the condition in which nutrients are in the substrate, but the roots cannot absorb them because of chemical bonds. It usually occurs because the pH changes to a value that is not in the correct range. The signs are the same as the signs of a deficiency.

The Nyquist rule is that the sampling rate must be a minimum of two times the frequency of the fastest cycle that you must find. If the rate is lower, you will read the cycle incorrectly, or the data will show a cycle that does not occur.

An OOS (Out Of Specification) is a test result that is out of the accepted limit. It starts an investigation before the decision to release.

An opening is a gap in a wall, for example a door, a pass-through or a roller door. The data give its position along the wall, its width and its top (head) height.

In oscillation, a loop makes corrections that are too large, in one direction and then in the other direction. The loop does not become stable. Usually the loop operates too quickly, too strongly, or makes corrections for noise.

The P0-P3 phases are the four irrigation stages of each day. P0 is the morning dryback, P1 is the ramp-up, P2 is the maintenance, and P3 is the stage before lights-off (emergency only).

PAR (photosynthetically active radiation) is the range of wavelengths from 400 to 700 nm that plants can use for photosynthesis. Lumens, lux and watts do not measure PAR. Thus they do not show the performance of a grow light for plants.

A parasitoid wasp is a very small wasp that is not dangerous to persons, for example Aphidius or Encarsia. The wasp puts eggs in a host pest, and the larva becomes larger and kills the host pest. These wasps are important for aphids and whitefly.

Part A (Pro Core) is the primary part of Athena Pro Line. It contains a large quantity of calcium and nitrogen. Always dissolve it in the water first.

Part B (Pro Grow / Pro Bloom) is the second part. It contains sulfates and phosphates. Add it only after Part A dissolves fully and mixes equally in the water.

A pause point is a time that has a name, at which you do a short checklist, for example lights-on, the first irrigation or pre-dark. A pause point replaces one long sheet that you do at random times.

PCBU is the person conducting a business or undertaking. It is the term that the Health and Safety at Work Act 2015 of NZ uses for the employer, who has the legal duty.

Peat is bog moss that is not fully decomposed. It has a high air-filled porosity, it is acid, and it has a high CEC. Peat is the primary component of most soil mixtures in bags.

Pencil-whipping is the record of a check as done when the person did not do the check. It is the usual result when a check is too slow, when no person has the task, or when no person uses the result. It is not only because a person is not careful.

Permittivity (dielectric constant) shows how strong the effect of an electric field is on a material. The value is very high for water (approximately 80), approximately 3 to 5 for dry substrate, and approximately 1 for air. Thus a capacitance sensor can calculate the water content from this difference.

Permittivity is a property of a material that shows how strong the effect of an electric field is on the material. Water has a very high value of permittivity. Thus a moisture probe measures the permittivity and changes it to the water content.

A PGR (plant growth regulator) is a plant hormone that you add to the medium to control growth. Cytokinins increase the growth of shoots. Auxins increase the growth of roots.

pH is a value on a scale of 0 to 14. It shows how acid or alkaline the water is. You usually adjust a nutrient solution to a pH of approximately 5.8 to 6.2.

The pH Down solution is an acid, usually phosphoric acid. The pH Up solution is alkaline, usually potassium hydroxide. You use them to adjust the pH.

A pH lockout is a condition in which a nutrient is in the root zone, but the plant cannot absorb it. It occurs because the pH of the root zone is not in the range in which that nutrient stays in solution.

The pH/EC gate is a safety check. It stops irrigation when the pH or the EC of the source tank is out of the limits that you set (default pH 5.8-6.2). It also sends an alert to your mobile device, with the alternative 'Irrigate Anyway'.

The phase of a row is its position in the cycle of each day. P0 is the morning dryback, P1 is the ramp-up, P2 is the maintenance, and P3 is the time before lights-off and the night.

Photoinhibition is the condition in which a leaf absorbs more light energy than it can use. As a result, photosynthesis decreases and damage to the leaf occurs.

The photoperiod is the number of hours of light and the number of hours of darkness in each day. You write it as hours of light/hours of darkness. For example, 18/6 is for vegetative growth, and 12/12 causes flowering to start and to continue.

A photoperiod plant starts flowering only when the hours of light in each day decrease to approximately 12. Regular seeds and feminized seeds give photoperiod plants.

Phytochrome is a pigment in a plant that senses red light and far-red light. It changes between the active condition (Pfr, 'it is day') and the condition that is not active (Pr). It measures the length of the continuous period of darkness and starts the flowering signal.

PIC/S PE009 is the Guide to GMP for Medicinal Products of the Pharmaceutical Inspection Co-operation Scheme. It is the reference standard, and the manual has a structure that agrees with it.

A pistil is a thin hair that extends from a bud site. It is white when it is new, and it becomes orange or brown during ripening. It is an approximate sign of the time to harvest, and it is not accurate.

The plant state is the condition of the plant that the system calculates (for example, on-track, stress, or steering generative). The system uses many signals together, and not one instrument.

Pore-water EC is the salt strength of the water that touches the roots (not the bulk EC). It is the EC that the plant gets.

Post-harvest is all the tasks that you do after you cut the plant. The tasks include drying, trimming, curing and storage.

PPE is personal protective equipment, and PPPE is plant and personal protective equipment. In a grow room, the same gown, gloves and protective covers give the crop protection against the person, and give the person protection against risks.

PPF (photosynthetic photon flux) is the total number of PAR photons that a fixture gives in each second (umol/s). It does not show where the photons go. To get the efficacy, divide the PPF by the power of the fixture in watts.

PPFD is photosynthetic photon flux density. It is the quantity of light on the canopy that the plant can use, in µmol/m²/s.

PPFD (photosynthetic photon flux density) is the number of photons in the PAR range that one square meter receives in each second. You measure it in micromoles for each square meter for each second (umol/m2/s). It shows how bright the light is at the canopy, and you read it with a quantum meter or PAR meter.

PPFD is the intensity of light at one time. DLI is the total quantity of light that the plants receive in one day. The system monitors the DLI up to this time, and not only the PPFD at one time.

A PPFD map (PAR map) is a grid from the manufacturer that shows the PPFD across the area below the fixture for specified hanging heights. Use the grid as a start point. Then measure the PPFD with your meter at the canopy height, to make sure that the grid is correct.

PPM (parts per million) is a unit for the concentration of nutrients in water, and the PPM value changes with the EC value. Different scales change the EC value to a PPM value. Thus the EC value is the same for all meters, and the PPM value is not.

PPM (parts per million), or TDS (total dissolved solids), is the total weight of all the materials in solution in water. PPM meters change the EC value to a PPM value with a 500 scale or a 700 scale. Thus two different meters can give different readings.

Pre-buffering is the procedure in which you soak coco that you cleaned with water in a solution of calcium and magnesium. Thus the exchange sites of the coco do not remove Ca and Mg from your feed.

A precipitate is a solid that comes out of a solution. It occurs when ions that are not compatible, for example calcium with sulfate or phosphate, mix at a high concentration.

A pressure cascade is a sequence of air pressures that you set. A clean room has a higher pressure than the next room that is less clean. Thus air always flows from the clean room to the room that is less clean, and contamination cannot move to the product.

A preventative agent is an agent that you put in the crop before pests come. It stays in the crop on an alternative food. A curative agent is an agent that you release to decrease an outbreak that is in progress and that becomes larger.

Probe drift is the condition in which the accuracy of a pH probe decreases gradually with time. Replace the probe when the drift is more than approximately 0.2 pH between calibrations.

A PTZ camera is a pan-tilt-zoom camera. It can turn and zoom to monitor a movement. Here it is for coverage of intrusion on the roof.

Pythium is a water mold and a pathogen that causes root rot. It increases in number quickly in a reservoir where the water is warm (more than 23 °C) and the oxygen content is low.

QA (Quality Assurance) sets the quality system, monitors it, and makes release decisions independently of production. QC (Quality Control) does the sampling and the testing.

QA (Quality Assurance) is the unit (not production) that makes the decision, with a signature, to release a batch to the market.

A QMS (Quality Management System) or PQS (Pharmaceutical Quality System) is the group of responsibilities, procedures, operations and resources with which an organization controls quality. The manual uses the two names for the same system.

QRM (Quality Risk Management) is a method for decisions on risk, as in ICH Q9. You use it to find, examine and control risks in the system. You also do a review of the risks and give information about the risks.

The Quality Manual is the top document of the quality system. It gives general information about the quality system, and it refers to the procedures and records below it.

Quarantine is the procedure in which you keep new plants apart from the primary crop. When you receive the plants, clean them. Hold them for a minimum of 2 weeks and monitor them before you put them with the primary crop.

Quarantine, Released and Rejected are the three statuses of material. Material can have only one of the three statuses. The status of the material and the status in the system must always agree.

Raycasting (picking) is the method to find which 3D object you select with the mouse. The software sends a ray that you cannot see from the cursor into the scene.

Reactive oxygen species are molecules that cause damage to the leaf tissue and cause bleaching. The plant makes these molecules when it absorbs light energy that it cannot use. This occurs when there is too much light, or when there is not sufficient CO2 to use the energy.

Read-do and do-confirm are the two types of checklist. In a read-do checklist, you do each step when you read it, for example for setup or calibration. In a do-confirm checklist, you do the tasks without the checklist, then you stop and make sure that you did all the important items.

The recovery floor is the lowest water content from which a rockwool block can become wet again, equally, from the dripper. At a value less than the floor (approximately 25 to 30% WC), channeling occurs in the fiber and the inner part of the block stays dry.

A register is one controlled document that gives an index of records of one type (for example deviations, CAPAs, documents). It becomes larger only when you add rows.

A regular seed is a seed without treatment. It gives approximately equal quantities of male plants and female plants.

The REI (re-entry interval) is the mandatory time that you must wait after a spray before a person can safely go into the room again. A label on the door shows the REI.

Relative humidity (RH) is the quantity of water vapor that the air contains, as a percentage from 0 to 100%. You keep the dry room at 60% RH.

To render is to show the 3D scene as an image on the screen. The software does this many times each second. Thus you can control the scene.

A representativeness fault occurs when the probe works correctly, but its local volume of 1010 mL is not typical of the zone (channeling, air gap, moved probe). The reading is correct for the local volume, but it gives incorrect information about the zone.

Residual solvent is the remaining solvent (for example butane and ethanol) in a completed extract. It is a primary safety test, with specified maximum limits in ppm.

Resolution is the smallest change that a sensor can show (0.001 m3/m3 here). Accuracy is how close the value is to the correct value (+/-0.03 with the general equation, +/-0.01-0.02 after calibration). The two are not the same.

Reverse osmosis (RO) is filtration in which you push water through a semipermeable membrane. The membrane removes most of the minerals in solution, and the water has almost no PPM (usually 0 to 10 ppm TDS).

RH is relative humidity. It is the percentage of moisture that the air contains compared with the maximum quantity that the air can contain at that temperature.

Ripening is the last phase before harvest. In this phase, the pistils darken, the trichomes come to maturity, and the plant moves the nutrients that it keeps into the buds.

Rockwool (stone wool) is an inert medium of fiber from molten rock. It drains freely, it holds a large quantity of water, and it has almost no buffering. It is alkaline until you soak it.

A rockwool cube is a plug of mineral fiber that holds water and air. A cutting makes roots in it. A peat plug has the same function.

The root zone is the wet substrate directly around the roots. The uptake of nutrients and water occurs there.

A rooting hormone is a gel or liquid that contains indole-3-butyric acid (IBA), which is a synthetic auxin. Auxin is a plant hormone for roots. You apply the hormone to a stem after you cut the stem, to cause the stem to make roots.

An RP (Responsible Person) is the person who has the legal responsibility for the tasks in the regulations. The RP monitors these tasks, gives approval to release a batch, gives approval for recalls, and is the person that the regulator contacts.

Runoff is the nutrient water that is more than the pot can hold. It flows out of the bottom of the pot during or after irrigation.

Runoff (drain) is the water that flows out of the bottom of the pot.

A sachet or release box is a container, such as a pouch, that you hang on the plant. It releases predator insects onto the plant. It keeps the carrier material out of the irrigation system.

Safe headroom is a lower-confidence-bound estimate of the quantity of water that you can add before the pot is full. It is the only headroom number that gives approval for a shot.

Sampling cadence is how frequently you record a measurement. It must agree with the biology. It must be sufficiently fast to find the changes in the plant, and sufficiently slow to prevent a record of noise that has no value.

The scene is all the objects in the 3D model: slabs, walls, benches, lights and cameras. The model holds them together in one structure.

The schema is the agreed structure of the data file. Here it has only four types of record: rooms, walls, equipment and devices.

Scouting is a regular visual inspection of the plants and the traps. You do the inspection to find pests, damage or disease when they first occur.

SDI-12 is the digital serial protocol that the TEROS-12 uses to send the VWC, EC and temperature. A value that does not change, that is NaN, or that is at a limit of its range is a hardware fault and not data.

The seed coat is the hard outer shell of the seed. It gives protection to the embryo until the conditions are correct for the seed to germinate.

The sensible heat load is the dry heat that a grow room must remove, and it comes almost fully from the lights. Nearly all the power of the fixtures becomes heat, and this heat increases the air temperature and is the task of the air conditioner. As an estimate, the watts of light that go into the room are equal to the watts of dry heat that you must remove.

Sensor fusion is a method to use the signals of some sensors together. Each signal has errors. The method makes one better estimate of the condition, and it gives a confidence value that shows how accurate the estimate is.

A setpoint is the specified number that you give to the equipment. The equipment tries to get this number (for example, 24C for the temperature of the room).

A setpoint is the specified value that a controller tries to keep at this time. A target is the wider result that you want to get for a period of days.

The shade avoidance response is a condition of plants that are too close to each other. The plants use energy to make the weak inner branches longer in the direction of the light. They do not use this energy to make flower of good quality.

The shared-drain puzzle (sump puzzle) occurs when the water from some rooms, from the AC and from the dehumidifier goes into one bucket. Thus you cannot know which source caused a flush.

A shot is one small irrigation event. The size of a shot is a percentage of the water capacity of the pot (for example, a 5% shot).

A signal is a change in the plant or in the root zone that is important for your control. A signal can be a trend that continues, a step change that has a known cause, or a rhythm that occurs each day.

A signal is a change that occurs in the plant or in the root zone. Noise is a small random change from the sensor or from the environment, and it does not show a change in the plant. Good control uses the signal and ignores the noise.

The signal-to-noise ratio (SNR) is the strength of the signal compared with the strength of all other changes in the data. When the SNR is high, the data are stable and easy to read. When the SNR is low, the data have many changes, and the control adjusts for each change.

Sodium (Na) is a salt that is not a nutrient. Well water or coastal water can have a high quantity of sodium. A high quantity of sodium decreases the uptake of nutrients, and thus it is important to select RO.

A solenoid valve is an electrically operated valve. It opens or closes the flow of water when the relay board operates it.

An SOP (standard operating procedure) is a written instruction, with steps, for a task. It lets all personnel do the task with the same correct steps each time.

A source is a leaf with sufficient light that makes more sugar than it uses. A sink is a flower, a root or a leaf in shade that uses more sugar than it makes. When you open the canopy, the sinks that are in shade become sources again.

Special-cause variation is a change that has a cause that you can find. Something in the operation changes, and the variation is out of the control limits. You must do an investigation.

Specific yield (S) is the change in VWC for each mL of water that you supply (formula dVWC/delivered_mL). When S becomes almost zero, it is a possible sign that the pot is full, but it is only a possible sign.

The spectrum is the mixture of the colors of light (wavelengths) that a fixture gives. Blue (400 to 500 nm) gives compact growth. Red (600 to 700 nm) causes flowering and is the range with the highest efficiency for photosynthesis.

Spreading is the procedure in which you pull the branches away from the primary stalk and put them in the openings of the trellis. Thus light and air go to the middle, and the branches fill the canopy equally.

Statistical process control (SPC) is a method from manufacturing. It uses the recorded data of the operation to find if a change is only usual noise, or a signal for a correction.

The stem-snap test is a test in which you bend a stem to find if the plant is dry. If the stem breaks and does not fold, the plant is almost sufficiently dry.

A sticky trap is a sheet with a tacky surface, usually yellow or a different color. It catches pests in the air. Thus it gives an indication of pests in the first stage, and you can monitor the number of pests.

Stippling is a group of small points with less color on the leaves. It occurs when pests make holes in the cells one by one and absorb the sap. It is a usual sign of spider mites and thrips.

Stretch is the fast vertical growth in the first 2 to 3 weeks of flowering. In this time, the plant can become almost two times higher. Then the plant makes buds.

Subculture is the task to move the tissue of a culture to new medium. You do the task again at intervals of a small number of weeks. Thus the cultures do not die and continue to increase in number.

A substrate is the material in which the roots stay. The examples are coco coir, rockwool, peat and soil.

A substrate (growing medium) is the material in which the roots of a plant extend. It holds the plant in position, and it contains water, air and nutrients in solution.

A substrate (medium) is the material in which the roots extend. It can be coco coir, rockwool, water (hydroponics) or soil. The buffering of the pH in the root zone is different for each type of substrate.

The substrate EC is the strength of the salt in the water in the substrate, where the roots are. Use this reading for the control, and not the EC of the dripper or of the drain.

A substrate probe is a sensor in the medium (here GroundWork). It sends the VWC and the EC for a zone.

Substrate-specific calibration is the replacement of the general equation of the probe with an equation that you calculate for your media. The accuracy of the VWC becomes better, from +/-0.03 to +/-0.01-0.02 m3/m3. It is mandatory for accurate steering.

Sugar leaves are small leaves around the bud with trichomes on them. You cut them from the bud with scissors during trimming.

System enabled is the primary arm/kill switch. When it is OFF, no shot occurs. Auto irrigation only stops the automatic shots, and you can apply manual shots.

Tampering is an adjustment of the operation for common-cause variation, as if this variation is special-cause variation. Deming showed that tampering increases the variation of the operation.

A tank mix is a mixture of two or more products in one spray tank. Mix only the products that the label lets you put together, and add them in the sequence on the label.

The taproot (radicle) is the first white root that extends from a seed. It becomes longer in the down direction, to hold the plant in position and to find water.

A target is the result that you want to get (for example, a good transpiration rate). A setpoint is only an indicator of the target.

Telemetry is the sequence of numbers that your sensors send. The numbers include the temperature, the humidity and the moisture.

Terpenes are oils with an aroma. They give each cultivar its aroma and its flavor. They evaporate if the flower becomes too dry.

The claw is the condition in which the tips of the leaves bend down. It is the usual sign of toxicity of nitrogen (too much feed).

The flip is the change of the photoperiod from 18/6 to 12/12, to cause flowering. The lights are on for a smaller number of hours. Thus the DLI decreases by approximately 28% if the PPFD does not change.

Three.js is a code library with no cost that many persons use. It shows 3D scenes that you can control, in a usual web browser. You do not install software.

Tissue culture (TC) is the growth of plant cells, tissues or organs in a vessel without microbes. The plant material stays on a gel with nutrients and not in soil. When you use tissue culture to make many copies of a plant, the name of the method is also micropropagation.

Tone mapping is the step that changes the light intensity of the scene into an image that looks correct. With ACES tone mapping, surfaces of pure white become too bright and show no detail. Thus use a warm off-white.

Topping is the procedure in which you cut the top tip of the plant. The plant then does not become higher, and the branches below the tip become two or more new tops. As a result, the plant becomes wider and has more branches.

Total porosity is the fraction of a substrate that is open pore space (air plus water) and not solid material.

Totipotency is a property of plant cells. One plant cell can make a new plant with all its parts, when the cell gets the correct nutrients and hormones.

Toxicity is the condition in which the plant has too much of a nutrient, or too much salt in total. The leaves are usually dark green and glossy, with tips that bend down, and the tips have tipburn. The signs are opposite to the signs of a deficiency.

Traceability is the property of a product that lets you trace it back and forward through each step and input. It is necessary for recalls and audits.

In transpiration, a plant pulls water up and releases it as vapor through its leaves. Transpiration is a primary cause that connects water, heat and humidity.

A transpiration proxy is an estimate of the rate at which the plant transpires. The system calculates it from the VPD, the light and the change in the water content of the substrate.

The transpiration stream is the continuous flow of water from the roots to the leaves, which the plant releases as vapor through the stomata. The flow moves the nutrients in solution up in the plant, and calcium moves almost fully in this flow. Thus weak transpiration shows as a calcium deficiency when the tank is full.

Transplant is the movement of a clone with roots from its cube into a larger container or block. This starts the vegetative stage.

A trellis is a horizontal net above the canopy, and the plants become higher through the net. Initially, the net holds the branches apart, and subsequently it holds the heavy buds in position. SCROG is the short name for screen of green.

A trichome is a very small gland of resin on the buds. It contains most of the THC and the aroma. The color of the trichome (clear, milky white or amber) is the primary signal for the harvest.

Trichomes are the glands of resin on the bud. They contain THC, terpenes and flavonoids.

True leaves are the usual cannabis leaves, with serrations on the edges. They follow the cotyledons. When the true leaves occur, you start to apply feed.

A two-part nutrient is a nutrient system with two parts: Part A and Part B. You must add the parts to the water one after the other. If you mix the parts when they are concentrates, a chemical reaction occurs and you cannot use the batch.

A two-point calibration is the calibration of a pH pen with two known buffers, usually pH 7.0 and then pH 4.0. Thus the pH pen gives accurate readings across the range that you use.

Uniformity shows how equally the light goes to all the parts of the canopy. You read the PPFD at nine grid points and divide the lowest value by the average value. A value of more than 0.75 is sufficiently equal.

UV-B is ultraviolet light of approximately 280 to 315 nm. Some growers add it in the last stage of flowering to try to increase the trichomes and the potency. The data do not agree, and UV-B causes risks to the eyes, the skin and the plants (stress).

The V-model is a qualification system for equipment. It connects each design stage to a check that agrees with that stage (Design, Installation, Operational and Performance Qualification).

Validation (qualification) is the evidence, in documents, that facilities, equipment, utilities and operations do their specified tasks.

VPD shows how strongly the air pulls moisture from plants. It is one number that you calculate from the temperature and the humidity. This number changes the rate at which plants transpire.

The vegetative mode and the generative mode are the two steering modes. They select the dryback targets and the EC targets that the engine uses. The vegetative mode keeps the plant wet and in bulking, and the generative mode causes stress and flowering.

The two steering targets are the vegetative target and the generative target. The vegetative target increases the growth of roots and leaves (longer drybacks, lower EC). The generative target increases flowering and fruit (shorter drybacks, higher EC).

Viability is the condition in which a seed has life and can germinate. The viability decreases when you keep the seeds for a long time or in incorrect conditions.

A viroid is a pathogen with a smaller number of parts than a virus. It is only a short loop of RNA, and it has no protein shell.

The volume of influence is the part of the media that a probe senses. For the TEROS-12, it is approximately 1010 mL. This volume is large for a dielectric probe, but it is only a local sample of one position.

Volumetric water content (VWC) is the fraction of the total volume of the media that is liquid water, in m3/m3. A value of 0.34 shows that 34% of the volume of the pot is water. It is the primary number for irrigation steering.

VPD (vapor pressure deficit) is a value in kPa that you calculate from the temperature and the humidity together. It controls the rate at which a plant transpires. The procedure here uses a VPD of 1.2 to 1.5 kPa.

VPD shows how strongly the air pulls moisture from the plant, and it causes transpiration. You measure it in kPa (for example, 1.4-1.6). The correct value is different for each growth stage.

VRWE (Virtual Root-Zone Water Estimator) is software that calculates an estimate of the water in the root zone of a plant. It uses some signals together, and then it selects the irrigation. It does not use only one moisture probe.

VWC is the quantity of water in the substrate of the root zone, as a percentage of the volume of the substrate. It is a primary signal for crop steering.

Water activity (Aw) shows the quantity of free water that is available to microbes, as a value from 0 to 1. An Aw of <=0.55–0.65 prevents the growth of mold and yeast.

The water balance is the water that you supply (irrigation), minus the water that the plant uses, minus the runoff. You calculate it continuously. It is equal to the estimate of the water in the pot.

Water content (WC%) is the part of the volume of a block or of a pot that is water at this time, as a percentage. In rockwool, the WC is the one value that you control.

Water-holding capacity is the part of the pore space of a substrate that keeps water after the substrate drains. You give it as a percentage by volume.

A wet trim is a trim that you do before drying. A dry trim is a trim that you do after the hang-dry. The source procedure uses a dry trim.

Wet weight is the weight of the plants immediately after you cut them and before you dry them. You compare it with the dry weight to get the dry-to-wet ratio.

The withholding period is the time that is necessary after a treatment before you can harvest the crop as a product. Thus the residues stay less than the limits.

A zone (row) is one of the 3 sections of the room that you control independently. Each section has a pair of probes and a valve. All sections get feed from the same tank.

A zone (table) is one of the six grow tables that you control independently. Each table has a valve, a probe and a phase state.