That soil mix is pretty 'hot' for seedlings. Get some big holes in your cup and flush it out well. Generally, you should hold off on a compost based mix until you are ready to start feeding as the 5th set of adult leaves is starting to show. You should be totally fine, but you DO need to flush that plant. Luckily, you've got all that perlite in there and it will be VERY easy.
stinkyattic Reviewed by stinkyattic on . First signs of heat stress? I've got two seedlings growing in my seedling box, a gutted pc case with 2 6500k cfls in it and a pc fan running for ventilation. The taller of the two is starting to show yellowing around the edges of the leaves and 1 of them is slightly curling up the others seem fine. The shorter of the two plants doesn't exhibit any yellowing on it at all. I doubt its nute burn as the seedlings are in a mixture of humus and manure with perlite added in in about a 2 to 1 manure to perlite ratio. The manure Rating: 5