Lettuce nutrient schedule
Per-stage nutrient targets for Lactuca sativa across 2 documented growth stages, with a target pH of 5.6–7.
Nutrient schedule
Targets in ppm for the elemental nutrients most commonly tracked in home hydroponics. EC is shown per stage where the cited source publishes it; absence of a stage EC is intentional and not a data gap.
| Stage | EC (mS/cm) | N (ppm) | P (ppm) | K (ppm) |
|---|---|---|---|---|
| seedling | 1.2 | 125 | 31 | 215 |
| vegetative | 1.2 | 125 | 31 | 215 |
Target pH
Maintain reservoir pH at 5.6–7. pH controls how readily the roots can absorb each nutrient; outside this window the plant shows symptoms of deficiency even when the nutrients are physically present in solution.
Measure with a calibrated pH meter at the same time each day and log the reading. Drift of more than 0.3 units over 24 hours usually signals a reservoir change or a nutrient imbalance.
Sources
All numeric parameters on this page are drawn from the following extension and research sources.
- Cornell CEA Hydroponic Lettuce Handbook (Brechner & Both, 2013) (accessed 2026-04-20)
- UF IFAS Extension HS1422 — Growing Lettuce in Small Hydroponic Systems (accessed 2026-04-20)