Yellowing from bottom up. Growth stunted.

I have had four plants do this, all planted in the same soil. They grow well for about a week until they start to get their first set of 7, and the undergrowth begins. The lowest 2 leafs turn lighter in color to a lime green, and yellow by the next day, brown the day after that, and crunchy the next. This yellowing continues up from the bottom, and growth on top almost completely stops.

It is either nutes or heat. I know not to feed for atleast a month, but the soil has a little in it already plus fish emulsions from the first grow. I flushed to soil, but maybe not completely, Is it burning them? I am going to get some seedling soil either way today. My temps range from 82-94, there is decent circulation but it is an enclosed space so it gets hot. Occationally It has been over 100, is this causeing this stress?

that sounds exactly like nitrogen deficiency. Add a bit more nutes and also try to lower the temps.

If these are seedlings we're talking about, I'm inclined to guess that this is nute burn. You really shouldn't put babies in soil which contains nutes. Flushing may not work because the nutes could be time released. Transplant to a nutrient free soil immediately.

I really don't think this is due to heat. Cannabis is a tropical plant and has been growing in 100 degree temps for millions of years.

on reading your post a second time it might not be lack of nutes, what soil are you using?

The problem is using soil a second time around, its already full of toxic salts and using it again is only making it worse. whether or not it had fish emulsion is irrelevant, you need to use new soil for every grow. and use plain topsoil with no nutes, cheaper is better in most cases.

Just re potted into seed starting potting soil with added perlite. Should be good to go now. Its not normal for growth to stall at about the 4th leaf set is it? All 4 plants I have tried to grow have done this, hopefully this new soil will do the trick.