Brown Tips on young plant

I have a couple of plants that are about two weeks old under a 250 watt about a foot and a half from them temps are in the low 80's so not too much of a heat problem, But the two first round leaves that came out started to yellow from the tip and now there about brown all the way up. Now starting on the first fan leaves it looks like it is doing the same thing yellow tips then a little brown but when the first new growth comes out it is all green then that happens. They were all planted in a good top soil and perlite that is not pre fertilized so I know there not burning so what could it be. also I have not over watered those pot are light before I re water. Thanks for the help

Sounds like what ever soil you are growing in is no good for what you are growing in it. If light,temp, water, and humidity (the above ground stuff) is good, then your problem literally lies in your soil.
So.....what exactly is "good top soil" lol?

its soil I have used to grow everything and anything eles grows fucking crazy in it once I fertilize. It is made here in the next city over, perlite and dirt pretty much ph of 6.5 drains real good but it has no ferts mabey it is getting ready for a low dose unless it could be bugs who knows I haven't seen any and its inside.

@ 2 weeks old it should not need any fertilizer yet. Have you grown MJ in this soil before?

Nope everything eles though we grow a bunch of veggies and fruit and never had a problem last time I used miricle grow and they came out awsome its weird shit I though MG sucked. Last time I screwed up kinnda, I used MG and fertilized the first week but let me tell ya they grew real fast and no burn. I guess it different every time LOL

I gave one of them some fert and that was it green and growing