If you are using CFL's they should be about 3 inches off the top of the plants to lessen the stretching also one CFL is not enough light for even one plant, you need a minimum of 55 lumens per Sq. Ft. or per plant and if the soil is old or being reused from previous plantings you should bake the soil in the oven at 500 degrees for 30 minutes to kill any and all bactiera that may be present including molds and mildew and as they said above you need good airflow (fresh in and spent out) I use 2 4 inch CPU fans from Radio Shack cost $21.00 ea. I have one attached to a filter at the intake and the other as the exaust attached to a carbon filter, (clean air in and cleaner air out):smokin: