Short and bushy is certainly a good thing for growing in doors. The browning on the edges may be cause by nutrient burn from your MG soil. MG has pretty aggressive fert in it that is hard for young/small plants to handle. I would consider transplanting into a different soil. I've been hearing a lot of good things about Fox Farms and Black Gold but am using cocoa fiber currently.

Best of luck to ya,
Poncho 'Milla