There is no great difference between growing tomatoes in a container and growing them in the ground, except that the space, being smaller, dries out and uses up nutrients faster. Beyond that, there are some decided advantages with pots, such as mobility and the ability to grow in places without gardens, such as patios, balconies and rooftops. If you are a conscientious gardeners, cultivating in pots could become your favorite way to grow tomatoes.
Choosing a Pot
Tomatoes require little space for their roots to grow well. A pot as small as 12 inches in diameter and height will suffice, though a larger pot will also ensure against soil drying and nutrient loss. Unglazed terra cotta pots are attractive, but plastic or glazed will do a better job retaining water. All pots should have at least one drainage hole in the bottom, and if you need to move pots on occasion, consider using a bucket or other pot with a handle. Large pot casters are helpful too.
Small Space Hybrids
The hybrid cherry tomato Sweet Baby Girl is very compact--a good choice for pots. It has the advantage of early fruiting, as well as extreme heat and cold tolerance. It is also both exceptionally prolific and disease resistant. Other hybrids especially suited to containers are Garden Pearl, Sugar Snack, Window Box Roma and the Basket Boys---both red and yellow varieties. For compact slicing tomatoes, try Better Bush or Biltmore.
Small Space Heirloom Varieties
For old-fashioned, tried-and-true paste varieties, try Roma, Napoli or Principe Borghese. Compact and flavorful slicing heirlooms include Japanese Black Trifele--a medium-sized, pear-shaped tomato with deep purple-black, crack-resistant skin. It is a heavy producer with rich, smoky flavor. Other good varieties for pots include Homestead, Arbat and Rutgers. For a small cherry type heirloom, try Grape---an early, heat- and cold-resistant variety with exceptional sweetness and high productivity.
It is especially important if you live in a hot, dry climate or if your potted plants are located on a concrete or brick balcony or patio to monitor the soil dryness in the containers. Masonry surfaces absorb and radiate heat from the sun and will quickly dry out or overheat the containers placed on them. It may be necessary to water potted tomatoes in such places more than once per day. Avoid overwatering, however. Tomatoes are particularly susceptible to mildew and wilt brought on by too-damp conditions; water only when the soil feels dry at least 1inch below the surface.
Tomatoes in pots use up nutrients very quickly. If these are not replaced regularly, tomatoes will not thrive and may stop producing fruit. Purchase an all-purpose tomato food for your plants, and follow manufacturer's direction for use. Or go organic and water plants with a thin manure tea made from well-rotted manure considerably diluted with water.