Experimental plant 2, the shortest one, is beginning to curl at the tip of the leaf.. does anyone know why this is happening? Both plant 2 and control plant 1 (the above post) are beginning to curl.. I'm assuming the yellowish tint in control 1 is because of overwatering (not touchin the water for a while)..

I added aluminum foil to the top of the grow bin to improve illumination.. can anyone be of help?