Tomato plants require a loose, well-draining bed of soil, six to eight hours of sunlight a day and an adequate supply of water and nutrients. These basics will provide the plant with the energy necessary to flower and produce fruit. When planting your seedlings, space the plants at least 2 feet apart to prevent overcrowding. Plant marigolds, onion bulbs and garlic bulbs around your tomato plants to aid in disease and pest control.
Plant your seedlings after any danger of frost and after you have prepared the ground. Add compost to the soil before planting so your tomato seedlings will have access to nutrients through their developing root systems.
Plant the tomato seedlings so that approximately one-third of the main stem is buried in the soil. This encourages rooting along the buried stem, making for a stronger root system. Deep planting also protects the plants from damage from high winds or root exposure caused by compacted soil due to rainfall.
Tomato plants do not like "wet feet"; their roots become waterlogged in constantly wet soil. Allow the soil to dry out between waterings, but do not allow the soil to remain dry. Test the soil around your seedlings every few days by pushing your finger into the soil. If you feel no moisture, water your plants. If the soil is still moist, wait a day and test again.
Establish a regular schedule as the plants grow. As the temperatures warm up, and the plants have established their root systems, water every five days. If the leaves curl or turn yellow, increase the watering schedule to every three days. If the stems of the plants are "pliable", decrease to every seven days. Adjust the schedule to accommodate higher temperatures and amount of rainfall.
Provide a support system for your tomato plants. Tomato cages are circular wire fencing with large spaces between the wires and are available at garden centers. Cages keep your tomato plants upright, thus keeping the branches from sprawling along the ground. The large spacing between wires allows access to the plant for harvesting.
Trellises are also a viable means of support, as are stakes. With either of these, you tie the plants to the supports with string, continually tying them off as the plants grow.
If you elect to use a commercial fertilizer, choose one designed specifically for tomato plants. Tomato plants require equal amounts of nitrogen, phosphorous and potassium. General-purpose vegetable plant fertilizers are likely to be too high in nitrogen, resulting in dense foliage and minimal fruit.
An organic fertilizer, such as your own compost, may be applied to your tomato plants as side dressing. Add a layer of compost to either side of each of your tomato plants every two to three weeks. The layer should be approximately 1/4 inch thick and placed 4 to 6 six inches away from the base of the plant.