Correcting Lockout — The Flush-Diagnose-Rebuild Protocol
A decision tree that separates true deficiency from pH lockout from salt-stacking EC creep, and the corrective-flush numbers (½-strength feed, media-volume math) that fix it in coco and rockwool without shocking the crop.
The foundational micros lesson makes the core point: most field 'deficiencies' are pH-driven lockout, not a real shortage. This lesson is the procedure for proving which one you're facing and fixing it. Three distinct failures all wear the same yellow-leaf costume: (1) true deficiency (the element isn't in the feed), (2) pH lockout (it's in the feed but chemically unavailable at the current root-zone pH), and (3) salt-stacking / EC creep (the root zone is so concentrated that osmotic stress and ionic antagonism block uptake). Treat them the same way and you'll make two of the three worse.
In pH lockout the element is already present — adding more raises root-zone EC without raising availability, pushing you toward failure #3. In salt-stacking, adding nutrient literally is the cause. Only true deficiency responds to 'add more,' and true deficiency is the rarest of the three with a reputable base. The correct first move in almost every case is the same: measure, then flush toward baseline — don't dose.
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