What are the best containers to plant tomatoes in on a small balcony?

make sure the container are large enough to accommodate the plants .all varieties grow differently.place a plastic saucer under the pot

We use 5 gallon buckets from home depot but that want solve problem for lower deck. Why not try large plastics drip pans for flower pots to catch overflow.

I use to use 5 gallon buckets also bought a pot that look like a barrel .Take a hammer and nail punch holes in bottom .bought a dollar tree or dollar store tray to sit it on . get bigger tomatoes now .Good luck .

You can use 5 gallon plastic pails for tomato plants. I spray paint mine with plastic spray paint . Drill two holes on either side of the pail about 3-4 inches up from the bottom. The space will act like a reservior and you will not have to water so often and the excess water will not be running on your patio.

http://www.ezfromseed.org/articles/tomato-container.htm

You can but I just fill the pails up with good quality soil. If you use aluminum cans it certainly will make the pail lighter as the roots never go down that far.