12 day old Buddah assorted autos. so confused.

My setup is a 600 watt MH, 20 in. from the top of the plant to the glass on the cooling-tube. I use Gardeners Pride soil 50/50 perlite. the temperature is 77-84F. I watered once when I planted the germinated seeds and didn't water for a week. seems they have halted growing and the leaves are turning a bright green/yellow color. PLEASE HELP

I have four in total, the other two were watered less and are have less of a purple stem. seems they are okay. I will post a picture of the entire setup shortly.

this is my setup. please let me know what you think. open to all critique.

Sounds like temp is a little high for autos,it's just nuts burn,they will be just fine,try to lower the temps,they don't need that much light at a young age,good luck bud

thanks green cat. I turned ballast to 50% and raise the light a bit. seems things are going fine.