HELP WHY ARE MY LEAVES TURNING YELLOW???

I have 3 two-week old plants and the leaves are turning very yellow i went out of town a couple days ago and couldnt water them at all and the lights were left on for 2 whole days...... do ya think if i just watered them thoroughly and put them back on an 18-6 schedule they will come back...ANY INPUT WOULD BE GREAT:D

No, if they are yellow it is a nute deficiency, lockout, lack of light, or heat stress.
So you need to read the sticky at the top of the plant problems section and answer those questions, then we can tell you how to save your plant.
I'm moving this thread into that forum btw.