To moist, and not enough nitrogen. Might be to wet, for your young tree to establish roots, root rot. This could stunt root growth. Whats under that tin of yours? im going to transplant today and give them the first taste of organic nutes thanks i was really worried .A couple of things.... Don't plant so deep into the party cups. The air becomes stagnant and the plant can't transpire properly. Your fan does little for strengthening the stems either. Leaves tend to drop when they need water or if they are being over watered. Kind of ironic I know, but you should know which is the case better than us. Are you watering every day?Food: The discoloration can be PH, but is more likely to be an N deficiency. My strain took about 14 days to show discoloration before it's first feeding. Keep in mind that MJ has a tap root that needs room to grow. You have those planted at the bottom of the cups leaving the tap root no room. I'd repot those asap and begin a week feeding of plant food.
