Follow this stage by stage. Aim is the target; stay inside the OK range; if a reading hits the Act if column, correct it. Jot what you actually measure in Your reading — a pencil is a sensor, and your notes are how the recipe gets better. The same numbers a controller would use as setpoint and alarm; you're the controller today.
| What | Aim | OK range | Act if | Your reading |
|---|---|---|---|---|
| Daily light (DLI) | 20.5 mol/m2/d | 13.6–28.75 mol/m2/d | < 11.2 or > 32.5 mol/m2/d | |
| Photoperiod | 16 h | — | — | |
| Air temp — day | 23 °C | 17–29.9 °C | < 14 or > 33.8 °C | |
| Air temp — night | 18.5 °C | 14.45–23 °C | < 11.9 or > 26 °C | |
| Humidity | 60 % | 46.75–74.75 % | < 38.5 or > 84.5 % | |
| VPD | 0.95 kPa | 0.68–1.26 kPa | < 0.56 or > 1.43 kPa | |
| CO₂ | 850 ppm | 595–1150 ppm | < 490 or > 1300 ppm | |
| Air changes | 30 ACH | 17–46 ACH | < 14 or > 52 ACH |
| What | Aim | OK range | Act if | Your reading |
|---|---|---|---|---|
| Nitrogen (N) | 150 ppm | 102–207 ppm | < 84 or > 234 ppm | |
| Phosphorus (P) | 40 ppm | 25.5–57.5 ppm | < 21 or > 65 ppm | |
| Potassium (K) | 200 ppm | 127.5–287.5 ppm | < 105 or > 325 ppm | |
| Calcium (Ca) | 160 ppm | 102–230 ppm | < 84 or > 260 ppm | |
| Magnesium (Mg) | 50 ppm | 34–69 ppm | < 28 or > 78 ppm | |
| Sulfur (S) | 65 ppm | 34–103.5 ppm | < 28 or > 117 ppm | |
| Root-zone temp | 20 °C | 15.3–25.3 °C | < 12.6 or > 28.6 °C | |
| Dissolved O₂ | 7 mg/L | 5.1–9.2 mg/L | < 4.2 or > 10.4 mg/L | |
| Substrate moisture | 55 % | 38.25–74.75 % | < 31.5 or > 84.5 % |
Watch for: aerial — condensation on cold surfaces (wet leaves invite disease), VPD drifting out of band. Root — deficiency on new growth, EC/pH creep; log a reading each visit.