Why are my leafs yellow?

I have 1 week old plants under a 400w hps, ive been follwing all instructions carefully that i have been givin but why are my leafs yellow? and they are looking a bit droopy.What am i doing wrong?

How are we supposed to answer that question???????????????????

I'm gonna venture a guess that you're actually paying too much attention to them. Let the soil dry out (if you're growing in soil) and cut back on the feedings.

Please give details. Soil?? Watering freq.?? Need much more info please. GL HH

If you have them in any sort of PVC tent (hydrohut, habitat, etc)...they will likely turn yellow, then whitish, then burn up like nute burn---it's awful.....also fluctuations in temperatures outside optimal ranges (70~85 day/60~75 night) can cause yellowing....also heat stress from the lights...sulfur deficiency....boron deficiency......check this link and scroll through until you see your problem.......it's saved my ass..............International Cannagraphic Magazine Forums - The Complete guide to Sick Plants,pH, and Pest troubles!