Killed another seedling...this time, im doing everything correct! What do you think?

Well I killed another seedling.. which was my fault. I added nutes to early and gave it nitrogen toxicity :/ I used some cheap ass soil from walmart that had horrible aeration and drainage...

New Grow im using.... ↓

Soil - Fox Farm Ocean Forrest
Lights - 400w MH for veg and 400w HPS for Flower
Nutes - Fox Farm- Big Bloom, Big Grow, Tiger bloom....which ill only use after 4 weeks or so.
Light cycle - 20/4 (autoflower)

I have a dimmable ballast so im going to start my seedling on 200w and then progressively increase the wattage.


I have a fan to blow away the heat and provide better ventilation. (didn't have a problem with this though)

Becareful with ffof as it has alot of added nutes and can possibly burn your seedling

Dang...Do you know if it has nitrogen in it? My strain is superrrrr sensitive to it and pretty much kills her everytime :/