If this is your first indoor grow you might want to get a mite preventitive like neem.I got mites early in flower phase and just had a bout w/powdery mildew...I read that the neem helps prevent that also.Luckily I caught both early and easily took care of both problems (Azamax for mites,3:1 water milk mix w/a drop of dishsoap in a spray bottle).I read in another forum yesterday that if you let your humidity get over 80% powdery mildew is almost a certainty and sure enough about 5 days before I found it I had plugged a humidifier into the wrong timer and it kicked on in the middle of the nite and I did'nt catch it till it was almost 90%. Anyway,it pays to keep a sharp eye on your leaves,especially the lower ones.