I am using 13 gallon tupperwares, the kind you find in wal mart and the like. They work wonderfully for 2 plants with sativa-like root systems. They would do well with 3 or 4 indicas flipped at 8 inches or so, or a massive sativa vegged for a month or longer. I LOVE these containers as they have a larger area that stays moist/grows thick roots at the bottom compared to 5 gal pots. My root systems in the 13 gal tupperwares blow my 4 gal square pots out of the water. The roots grow more similarly to hydro roots, thick and massed in the bottom 4 inches or so. With these big containers I think its important to veg more than just a couple days, as the roots have a lot of pushing out and exploring to do. Also, like with grow beds, the plants can share eachother's root space. Only prob I've run into is proper drainage and pushing enough nutes, but ive fixed that by upping my perlite until problems abated. If you go with 13 gal buckets (upright, cylindrical)i could see your drainage issues being even greater than mine, so be sure you use tons of perlite or greensand. Also, i use a layer of 2 inches of perlite onthe bottom of my containers to help prevent soggy spots, might help you too if you end up with signs of overwatering when you haven't watered in forever(probably more applicable in short, squat tupperwares than buckets)......hence poor drainage. All in all, i love the yields im getting off of massive containers and multiple plants per compared to anotherother vert set up near me thatis using 2 gal grow bags. If you can keep your plants from getting soggy, then big containers are the way to go. hope this helps
