Brand new grower, leafs curling under. how to fix? PIC

the lower fan leaves of my three week old trees are curling under and rolling under on the edges. earlier today the top leaves were very yellow but the flush fixed that but not the curling leaves. no discoloration accept for the tips curled under first and turned redish orange and then a black color. the leaves are a vibrant green beside that but still seem papery and just not healthy despite the color. i flushed out the soil by filling the pots till full, then drained, repeat, 6 times. would high temp cause this. thats what i hope the problem is, i have 8 two foot fluorescents surrounding the plants in a 2-3.5-4 foot cabinet. its not ventalated so i keep the door cracked. could my lights be whats causing the problem? or is it a nute problem. the ph is a steady 7.1 to 7.2. i dont know how to lower the ph to reach 6.5 in the soil, actually i dont even know how to test the soil for ph, only the water im watering. just please anybody with any info, im all ears. tell me what im doin wrong, iv got broad shoulders when it comes to saving my babys.


im a big fat lier and none of this shit was written by me, o and i found the pics on the internet. im just trying to be cool

Your leaves are curled because you flushed. They are over watered. Just let the soil try and they will perk right up.

no bro, this pic was taken before i flushed. theys been curling under for a while now, also its not your average curling under on just the tips. the edges are rolling under on both sides of each individual leaf, kinda lika a scroll with the rolls on the bottom. and they are very paper.