BigBill said: Tomato plants in my experience do not produce a root system large enough to reach the bottom of a 5 gallon bucket. I find when I dig them up at the end of the season, the root system is 8-10" round at most. I use large containers or pots that are 16" across. If I notice that it holds too much water, I drill 1/2" holes an inch up from the bottom of the container. Perhaps 6-8 per container.
It is a very dense and fibrous root system.
But Christine makes a good point, tomatoes do not like wet feet!
embermason said: I've been growing tomatoes in containers that I keep in my greenhouse. I use both 7 and 17 gallon plastic pots with four 3/8" holes equally spaced a out 3 inches up the side. None in the bottom. I have a 1 1/4" pvc pipe on the inside set 1 inch from the bottom. No drainage rock just good soil mix. I mostly water down the tube but often water through the mulched surface too. I have good vigorous growth on my various heirlooms, no BER or cracking and very minimal blossom drop.