First make sure you do not use regular soil. Use potting mix. With some research you can make 5-1-1 mix for yourself if you have the components available. It would be less than half the cost of the bagged potting mix. Avoid anything that says soil for use in the buckets. It will compact, it will not drain well. Your plants may start off looking great, then they all start to look sick, then die.

Ok that part is done. Now onto the what you can grow in them. Well just about darn near anything will grow in potting mix in the buckets. If you grow tomatoes in them stick with the bush types they will do great. Any peppers will do well in the buckets as well. Cuces, and squash will do fine in them.

It may be helpful to put some pea gravel that covers the bottom of the pot to keep the drain holes from plugging up. Also set them on something that allows the water to drain out of the bottom without the water pooling up in them.

Here's a somewhat offbeat idea. Grow earthworms.
-Terry

Here is a link that might be useful: worm culturing

I agree with the first two paragraphs of what centexan254 advised, but not the last point about putting gravel in the bottom of the pot. That will actually cause drainage problems because the finer potting mix above the gravel will hold onto water if it's in contact with bigger particles like pea gravel. If you are concerned about potting mix clogging the drainage holes, you can use old window screen to cover the holes. In practice, potting mix rarely escapes the pot. There's a lot of good advice about this kind of thing in the container forum, including a recipe for the 5-1-1 mix that many of us use in containers, which is in the link below.

Here is a link that might be useful: Container Soils

There's a container gardening forum that might be more help. I don't know how to link it, though. Go up to the top, click on back to vege gardening, then back up to the top and click on other forums, then look for container gardening. Good luck! Nancy

I grow basil in 5 gal containers. 20 plants, one per container keeps me going for pizza throughout the summer.

Or lettuce. I get good results with one gallon or less. However I also grow in five and fifteen gal containers. The larger sizes provide a better opportunity to leave plants unattended for two or three days. Also higher sides keeps mice and rabbits away.

Zeuspaul

Things I have grown in 5 gallon buckets: lettuces, spinach, chard, dwarf tomatoes, head of cabbage, head of broccoli, a head of cauliflower, some carrots, spring onions, basil, chives, mint, dill, sage, small hot pepper varieties and all kinds of flowers.

Not ideal and I'm not saying you get a lot or even normal sizes but if you keep expectations in line and feed regularly and water carefully it can be done.

Dave

IMO you can plant MOST varieties of peppers, eggplants and patio/bush tomatoes. For things like chard, basil, onions, lettuce .. 5gal bucket is unnecessarily deep and it is a waste of potting mix. I would rather plant those veggies in shallow planters.

Nothing says you have to fill the bucket full of mix. If the buckets are what you have to use, for shallow rooted plants, 1/2 full works fine.

But if you do fill it when planting shallow rooted plants you don't have to water it as often since the extra soil retains more water.

Dave

I just checked my basil from last year. The roots filled the tall #5 nursery pots. (5 gal buckets hold more soil than a #5 nursery container.) The longest root measured 17 inches.

The basil in smaller containers did not do as well as the basil in the #5's.

I water the containers every day in the heat of the summer and the smaller containers were difficult to keep up with. My location is warm to hot,dry and windy.

Zeuspaul