Plant problem (pics)

These are my plants. As you can tell some of them are a light green/yellow color and some of the leaves are starting to curl. I have them under 1 400wt HPS. Any tips to get them looking healthy again?

water lately that dirt looks mighty dry......and wat nuts u yousing?

How is the heat in there?

first, tell us what you been doing there lately
did you use fertilizer, if which and doses? do you pH everything? what about temps and humidity in your grow, and finally what kind of HPS you have and what is it distance to the plants?

my first intentional thought was heat stress since the serrated edges are curled up and the soil looks dry. but this only based on the pic without background info, so a long shot into the dark.

Do you ph test? What kind of soil is that? It does look dry. Is that foil? Do you have a moisture meter? Go to FAQ click on getting started.