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) | 19.5 mol/m2/d | 14.45–25.3 mol/m2/d | < 11.9 or > 28.6 mol/m2/d | |
| Photoperiod | 14 h | — | — | |
| Air temp — day | 21 °C | 15.3–27.6 °C | < 12.6 or > 31.2 °C | |
| Air temp — night | 11.5 °C | 8.5–14.95 °C | < 7 or > 16.9 °C | |
| Humidity | 67.5 % | 51–86.25 % | < 42 or > 97.5 % | |
| VPD | 0.7 kPa | 0.42–1.03 kPa | < 0.35 or > 1.17 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) | 125 ppm | 85–172.5 ppm | < 70 or > 195 ppm | |
| Phosphorus (P) | 40 ppm | 25.5–57.5 ppm | < 21 or > 65 ppm | |
| Potassium (K) | 220 ppm | 153–299 ppm | < 126 or > 338 ppm | |
| Calcium (Ca) | 150 ppm | 102–207 ppm | < 84 or > 234 ppm | |
| Magnesium (Mg) | 50 ppm | 34–69 ppm | < 28 or > 78 ppm | |
| Sulfur (S) | 70 ppm | 42.5–103.5 ppm | < 35 or > 117 ppm | |
| Root-zone temp | 18 °C | 13.6–23 °C | < 11.2 or > 26 °C | |
| Dissolved O₂ | 7.5 mg/L | 5.1–10.35 mg/L | < 4.2 or > 11.7 mg/L | |
| Substrate moisture | 60 % | 42.5–80.5 % | < 35 or > 91 % |
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.