Nutrient Lockout: When Feeding More Makes It Worse
Lockout means the nutrients are present but unavailable. The plant shows deficiency symptoms, the grower feeds more, and the buildup makes the lockout worse. It is the most common downward spiral in home growing.
Recognizing it
Multiple deficiency symptoms appearing at once, symptoms that get worse after feeding, and runoff ppm far higher than input ppm. A single clean deficiency is usually a real deficiency; three at once is usually lockout.
The two causes
pH outside the medium's range, which chemically blocks specific nutrients, and salt accumulation from overfeeding, which raises the osmotic pressure in the root zone.
The reset
Flush with three times the pot volume of pH-adjusted plain water. Check runoff pH and ppm at the start and end of the flush. Let the pot dry back. Resume at half strength and correct your pH going forward.
Frequently asked questions
- How long until the plant recovers?
- New growth should come in clean within 7-10 days. Existing damaged leaves will not recover.