Learner workbook

Name: __________ Date: __________ Route: demo / existing system / builder

You can pause, repeat and use a calculator. Explain your answer as if you were helping a friend. The numbers below are fictional teaching examples, not crop recommendations. Do not copy them into a live grow.

A small glossary

1. Explain a reading

The probe shows 60% VWC.

• What fraction of the measured sample's total volume is water? __________
• Is the rest all air? Why? __________
• Does the plant have exactly 60% of its usable water left? __________
• Does one reading establish that every pot in the zone is equally wet? __________

2. Capacity cards

Match each description to saturation, drained container capacity, or configured reference.

1. Pore spaces filled with water: __________
2. Number entered in the software: __________
3. Water retained after the stated drainage protocol: __________

Name three conditions you should record when establishing a container reference: __________

3. Dryback — first copy, then complete, then try alone

Worked example: 60% VWC falls to 45%.

Drop in percentage points = 60 − 45 = 15 points
Relative dryback = (60 − 45) ÷ 60 × 100 = 25%

Finish this example: 50% falls to 40%.

Drop = 50 − ____ = ____ points
Relative dryback = ____ ÷ 50 × 100 = ____%

Try alone: the peak is 60% and a field specifies 10% relative dryback. What VWC corresponds to that reference? __________

Explain why calling a 60-to-45 drop “15% dryback” is ambiguous: __________

4. Label the EC sample

Put feed, bulk substrate, pore-water, or runoff/extract beside each measurement.

1. A cup sampled from the supply tank: __________
2. TEROS 12's bulk conductivity measurement in the medium: __________
3. Conductivity of water in pore space, using an identified valid method: __________
4. Solution collected by a stated drainage/extraction procedure: __________

Can a high EC number alone tell you exactly which nutrient is excessive? __________

5. Trust the sensor?

The line is smooth, but its last timestamp was several hours ago. Another representative probe is changing. What do you check before changing irrigation targets? __________

6. Read a combined graph

On a demo graph, point to or write down:

The EC and VWC lines cross. Does this mean the readings have equal values? __________

The dashed overnight EC line connects two references. Does that guarantee the measured EC will follow it? __________

7. Shot volume: per plant and per zone

Our fictional zone has 20 plants, 5 L substrate per plant, two 4 L/h emitters per plant. A shot runs for 45 seconds.

Per-plant flow = emitters per plant × L/h each
Per-plant delivery = per-plant L/h × seconds ÷ 3600
Zone delivery = per-plant delivery × plants
Shot as % of substrate volume = delivery L per plant ÷ substrate L per plant × 100

• Flow per plant: __________ L/h
• Delivery per plant: __________ L, or __________ mL
• Total zone delivery: __________ L
• Shot as a fraction of substrate volume: __________ %

Ten identical completed shots would estimate __________ L per zone and __________ L per plant. Does this prove actual equal delivery or plant uptake? __________

Does that shot fraction guarantee the same increase in VWC percentage points? __________

Why can't we guarantee a daily total just by counting the shots drawn on an illustrative planning graph? __________

8. Move a line without operating a real pump

Open the isolated demo. Select a room and zone in Irrigation → Current day. If a plan owns the targets and they are read-only, practise on a suitable manual demo zone rather than disabling a real plan.

1. Record the saved P3 emergency floor: __________
2. Nudge the local draft by one allowed step. Describe which reference moved: __________
3. Did the observed crop data move? __________
4. Open the review. State the field, unit, room, zone and before/after values: __________
5. Apply in the demo and inspect readback. Then restore the original example value through the same review.
6. Explain why this was a threshold edit, not a guaranteed shot: __________

You have practised the interaction, not established a suitable live threshold.

9. What does each action do?

Complete the table before checking the answers.

Which of these proves physical isolation? __________

10. Compare two runs fairly

In History, choose a zone and an available comparison. Write:

• Same grow age or different ages? __________
• Same units, measurement type and time coverage? __________
• Actual history, saved run reference or current illustrative reference? __________
• Delivery measured, runtime-estimated or unknown? __________
• One observation supported by the data: __________
• One causal claim the data cannot establish: __________

If I create a run record today with a start date last month, does that reconstruct last month's targets? __________

11–13. What would you do next?

11. Stale moisture: the last valid reading is old and irrigation is holding. A friend says to lower the threshold to make it water. Your response: __________

12. Tank disagreement: the dashboard reports 80% full, but the installed low-level indication conflicts. Your response: __________

13. Water won't stop: the app says OFF but you can still see flow. Your immediate response, then investigation: __________

Your real-system handover and commissioning record

Complete with the responsible installer/operator. Leave unknowns explicitly unknown. A demo cannot pass physical tests.

Five-minute daily record

1. Identity and freshness: room/zone, date/time, sensor/controller ages.
2. State: phase, Why / next action, last irrigation, actual output status where confirmed.
3. Water: per-zone/per-plant delivery with source labelled measured/estimated; unexpected variation.
4. Feed and context: available tank/feed readings, contradictions, light/climate changes and physical observation.
5. Decision: no change / investigate / one justified adjustment. Record before/after, rationale, expected observation and when to check again. Verify readback if applied.

Change more than one thing only when justified; record it so later comparisons do not pretend to isolate a single cause.

Answers and explanations

1. 60% of the sample volume. The remainder includes solids and air. It is not a direct percentage of usable water left; a local probe does not establish zone uniformity.

2. Saturation; configured reference; drained container capacity. Useful conditions include medium, container dimensions/height, starting treatment, drainage protocol, probe placement/calibration and repeated results. A software field is not a physical measurement.

3. 40; 10 points; 10; 20%. A 10% relative loss from 60 is 6 points, giving 54% VWC. “15% dryback” could be mistaken for either 15 points or 15% of the peak, which would be 9 points here. State the convention.

4. Feed; bulk substrate; pore-water; runoff/extract. EC does not identify each nutrient's concentration or prove nutrition is balanced. A bulk-to-pore transformation needs identified assumptions and validity; do not silently rename the value.

5. Verify timestamps, entity availability, communications/power, units and probe condition/placement; inspect the actual medium and independent evidence as appropriate. Resolve unreliable data before interpreting it as crop response. Do not override protections to force watering.

6. No: two axes have different units/scales. No: the dashed overnight EC is a reference connection, not a validated prediction. Exact demo observations depend on session/time; assessment is correct identification, not a fixed screenshot number.

7. 8 L/h per plant; 0.1 L = 100 mL per plant; 2 L per zone; 2% of substrate volume. Ten identical completed shots estimate 20 L per zone / 1 L per plant. These are runtime/flow estimates unless independently measured; they are neither uptake nor proof of equal delivery. Water distribution, drainage, uptake and probe sampling prevent a guaranteed two-point VWC rise. Conditional P2/P3 events and actual conditions make a fixed daily prediction unjustified.

8. The draft threshold/reference moves. Recorded observations are not rewritten. A threshold is used by a rule; editing it does not guarantee a shot, and local edits require reviewed application before reaching HA. Always check the actual field's meaning.

9. A local draft; writes reviewed HA targets then requires readback; browser/site/room library only; stores a draft plan without arming; requests next-local-lights-on activation without enabling Watering; scheduled return to manual at next lights-on; stores run metadata/reference and starts no shots; affects all referencing blocks when that plan is later applied under its workflow; stops through software for the selected room. None proves physical isolation. An active plan owns its effective targets; Current day is read-only for those targets.

10. Accept an observation supported by the available trace/record, with coverage limitations. Do not infer a reconstructed historical target series from a newly saved current reference. A difference between runs does not isolate the cause when crop age, climate, media, calibration or other variables differ.

11. Investigate and restore trustworthy sensing; follow the installation's safe fallback procedure. Do not force a shot by lowering a safety threshold.

12. Treat the contradiction as unresolved. Verify physical level safely, instruments, level calibration and mappings. Do not assume the optimistic percentage proves a safe pump supply; use installed protections and isolation as required.

13. Use the installation's physical shutdown/isolation procedure immediately. Once safe, inspect valve sticking, siphon, output feedback/mapping and conflicting controllers with competent help. Software OFF is not proof of water cessation.

Teach-back and delayed check

Tomorrow, explain VWC and draft/apply/arm to someone without looking at these answers. About a week later, calculate dryback using new numbers, identify a stale trace and walk through physical shutdown with your local supervisor. These are proposed practice intervals; adapt to availability while revisiting rather than cramming.