leaf edges yelowing some kind of deficiency? (pic)

I noticed 1 of my 2 week old plants showing some signs of deficiency i think, theres only one like this and its my best 1, smells great since it sprouted and none of the others smell of anything, The edge of the leafs are yellowing, and im sure ive seen this problem somewere on here before. Any ideas?

Bump... anyone seen this before?

looks like it could be heat burn.... see how the yellowing is mostly on the upper leaves?

flush and see what happens?

YEP I SEEN SYPTOMS FOR THAT BUT THERE IS 6 MORE OF SIMULAR SIZE IN SAME BOX, WICH LOOK FINE, THERE ARE 7 PLANTS AND THIS ONE HAS HAD A STRONG WEED SMELL FROM SEEDLING, THATS THE ONLY REASON I CAN THINK ITS DIFFERENT IN APERANCE. Sorry for caps

That's a manganese deficiency. If you're nuting, stop. Go get better nutes. Careful with that stuff at early stages, you can create deficiencies. PH might need adjust too.

Get some vermiculite in that soil when you xplant.