Mi first Grow!

Nutrient salt toxicity from feeding too much or too often.........or both. Remember, in soil it is a schedule of plain water/plain water/feed/plain water/plain water/feed......so that the plants are only being fed every 10-12 days or so. They need to use up what is already there, before new nutrients are given/added. At this stage I would be giving just plain water for the next 3 irrigations and once resuming feeding, cut the strength by about a quarter, (while going to the plain water/plain water/feed routine too). Flushing with large amounts of plain water in the hope of a "quick fix" can release even more nutrient salts from the soil and cause the problem to become even worse.