First signs of burning due to over feeding or feeding too often.
Sativa dominant strains like SSH usually do just fine with half to two thirds strength nutrients.
Also, 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 10-14 days, which is plenty, as soil "holds onto" nutrients quite effectively.
Also, go easy on the defoliation....less leaves = less energy being made = less growth.