Oh yeah that's clearly... just by looking at the pics sprayed with something on the leaves. I did it one my very first grow attempt (which failed by week 2..but learned from it quite a lot)
The white spots may be from the lighting burning whatever is sprayed on the leaves... I can tell more from the white lines that sort of look like a stain on a carpet.
Once they sprouted(the seedling) then you no longer need to use a spray can.. just water...

->BackWoodDrifter did the job telling you what to do (+1:thumbsup
poker2 Reviewed by poker2 on . White powder on seedling I'm not sure of the problem this is only my second plant. and had the same problem on both I read it was sun bleach from spraying the leaves? it only happened to the first couple of leaves on my first plant and now it's happening again and I haven't sprayed the leaves much. Just curious as too what the problem could be? This happened within today, no powder was on the leaves this morning. Rating: 5