Nutrient Deficiency on hydroponic lettuce
What's Happening
Nutrient deficiency in hydroponic lettuce occurs when essential macronutrients (N, P, K) or micronutrients (Fe, Mg, Ca) fall below optimal concentrations in the nutrient solution. Unlike soil, which has buffering capacity, hydroponic systems depend entirely on precisely balanced nutrient solutions. Deficiencies manifest as chlorosis (yellowing), necrosis (tissue death), or stunted growth, depending on which nutrient is lacking. pH fluctuations outside 5.5-6.5 range lock out nutrients even when present.
How to Fix It
- 1
Test nutrient solution immediately with EC meter and pH test kit
- 2
Adjust pH to 5.8-6.2 using pH down (phosphoric acid) or pH up (potassium hydroxide)
- 3
If EC is low (<1.0): add concentrated nutrient solution to reach 1.5-1.8 mS/cm
- 4
For iron deficiency (interveinal chlorosis): foliar spray with chelated iron at 0.5g/L
- 5
For calcium deficiency (tip burn): increase calcium nitrate in solution by 20%
- 6
For nitrogen deficiency (uniform yellowing): add calcium nitrate or ammonium nitrate
- 7
Completely replace nutrient solution if multiple deficiencies present—do not supplement depleted solution
How to Prevent It
Monitor EC (electrical conductivity) daily—maintain 1.2-2.0 mS/cm for lettuce; test pH twice daily and adjust with pH up/down solutions; use complete hydroponic fertilizer formulated for leafy greens; change nutrient solution every 14 days; monitor leaf color weekly—uniform green indicates adequate nutrition; maintain pH between 5.5-6.5 for optimal nutrient uptake.