Those are what's referred to in the industry as nursery "trade sizes" and are not intended to duplicate a true liquid measurement but rather to standardize the sizing of plants in the commercial nursery industry. So comparing sized nursery containers to a 5 gallon bucket is really like comparing apples to oranges - one has absolutely no relationship or bearing on the other!! And FWIW, I would consider a 5G bucket an absolute minimum size for growing tomatoes. Might work OK for some smaller determinate varieties but I grow indeterminates in 20 or 25G containers and the root system will completely fill the container by the end of the season.

Thanks for the info on the BER. First year container gardening so this is a whole new experience for me. I made my mix myself, Peat Moss (1/2 bag), garden lime (3 handfuls), perlite (1 bag), composted cow manure (1/2 bag) and 10-10-10 (12oz cup) and 2 cups coffee grounds mixed up well in wheelbarrow. Buckets/Containers 5 gallon with 1 1/2" to 2" rocks in the bottom and holes in the bottom of the buckets for excess to drain.

I agree that its possible and that it takes more work in feeding and watering and that choosing smaller utlimate size of plants will help a great deal. A couple other suggestions. Rather than drilling holes in the bottom, try making just one horizontal saw cut, maybe 2" long, a couple inches up from the bottom. Much better water retention and it will still drain if you used a potting mix. If you can get 20 gal containers for anything like that price, I'd get several. Pots that big, in my climate serve lrg indeterminates very well. I dont even cut drain holes in them but if you have a very rainy spell you might need to build a mini well point to syphon excess water. If you don't have that rainy spell though, they'll be just dandy and your watering chores are much reduced. Again, only with potting mix, which confused me quite a bit when I started hanging around here. It must be regional thing. We have many products, and always have, labeled "potting soil" but has a light texture due to compost, humas, vermiculite etc. Many refer to this as soiless mix and can get kinda touchy about it :-) We do also have a few products that are labeled potting soil but you can tell from the heft, that un-ammended, are much too dense for containers and will not drain properly.

I never lifted the pot. I'll try that tomorrow. I've got a 3" hole in the bottom of the bucket. The dirt is down about 4" from the rim of the bucket in all of the pots. I turn the hose on and let the water fill up to the rim then shut it off. It doesn't start to fill immediately either. After about 30 seconds then the water start to collect above the potting mix. That weight trick is a good idea.