I did 2 months of veg. In a 5 gal pot Scrogged came out with about 2 1/2 oz'z Use 2 3 gallon buckets you will be alright. When i used my 5 gal the roots werent even bound to the pot. So 3 should be good enough. The average yield of a plant under a 150 watt should be around 2 oz's. My two cents...