Title. I have a grow in my 3x3, 3 plants. Two look happy and healthy, but one has been stressed recently and I can't seem to make it happy. They're all fed the same nutes at the same time. I've tried adjusting light and fans, hasn't helped yet.

Symptoms include downward leaf curl/clawing, some drooping of the leaves, and slightly less vibrant green coloring of the leaves vs. other plants. Any opinions?