Even though we have a large amount of land (by urban standards), we sometimes choose to grow certain crops in containers.
Two years ago, we experimented with growing tomatoes in upside-down buckets, with herbs growing in the top.
The results were mixed. On the plus side: harvesting was easy with everything up off the ground, and there was virtually no weeding. On the minus side: they required daily watering, and the plants were puny compared to the ones in the ground.
Last year, we reserved the hanging garden for grape tomatoes, and enjoyed the easy harvesting, but there were hardly any fruits to harvest.
This year, all the tomatoes are going into the ground. They just do better there for us.
On the other hand, we had some volunteer dill plants in one of the buckets last year, and they did great. Dill is particularly sensitive to competition from weeds, and the buckets filled with potting mix are both less weed-seed-infested than dirt and more conveniently reached than the ground.
We've also had success growing lettuces in planters on my neighbors' deck. The bunnies and woodchucks aren't great stair-climbers, and the slugs/snails dislike crossing the surrounding expanses of dry wood to get to the planters.
This year, we're planning to grow some additional crops in containers. I've already sown some tatsoi (a very hardy oriental green that can be eaten raw or lightly steamed/sauteed like spinach/chard) in a deck planter. The first set of lettuce seedlings is growing under lights indoors, and we expect to have a cold frame in place this weekend or next, so we can start a second sowing of lettuces indoors. Radishes and miniature carrots, which are as timid as dill when competing with weeds, will go into planters (probably the tomato buckets) when the weather improves.