That guide weedhound gave the link to is excellent
privatepile Reviewed by privatepile on . Seedlings yellow and droopy Two seedlings have become colored light yellow or light green and the leaves are drooping. These are 2.5 weeks old. One week-old seedling (now as large as the other two), however, is doing fine in the same grow space. The only difference is that it was planted in different soil (indoor/outdoor organic). Details: Dimensions: (3 x 2 x 1.5) ft, mylar-covered walls Lights: 2x 85w CFLs (total 10,000 lumens, or 3333 lm/ft²) Light cycle: 18/6 Temp: 60-70°F Vents: Passive intake, 20CFM Rating: 5