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) | 14.5 mol/m2/d | 10.2–19.55 mol/m2/d | < 8.4 or > 22.1 mol/m2/d | |
| Photoperiod | 16 h | — | — | |
| Air temp — day | 21 °C | 15.3–27.6 °C | < 12.6 or > 31.2 °C | |
| Air temp — night | 16.5 °C | 12.75–20.7 °C | < 10.5 or > 23.4 °C | |
| Humidity | 60 % | 42.5–80.5 % | < 35 or > 91 % | |
| VPD | 0.8 kPa | 0.51–1.15 kPa | < 0.42 or > 1.3 kPa | |
| CO₂ | 850 ppm | 595–1150 ppm | < 490 or > 1300 ppm | |
| Air changes | 22.5 ACH | 12.75–34.5 ACH | < 10.5 or > 39 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) | 185 ppm | 127.5–253 ppm | < 105 or > 286 ppm | |
| Calcium (Ca) | 150 ppm | 102–207 ppm | < 84 or > 234 ppm | |
| Magnesium (Mg) | 40 ppm | 25.5–57.5 ppm | < 21 or > 65 ppm | |
| Sulfur (S) | 60 ppm | 34–92 ppm | < 28 or > 104 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 | 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.