Using a trellis to grow tomatoes is one of the most ideal methods of growing tomatoes. This is because a trellis keeps the tomato plant branches and fruit away from the ground (to avoid disease), and more tomatoes are produced when the plant is growing vertically. Growing tomatoes on a trellis is more simple than you may think, and requires little supplies but a trellis.
Obtain a trellis for your tomatoes to grow on when the plants are still young. Secure the trellis directly next to the tomato plant if the plant is already growing, or else place a potted tomato plant next to the trellis.
Drape and wrap the tomato branches onto the trellis to avoid diseases and insect infestations the plant can pick up from dragging on the ground. Also, draping the branches on the trellis helps provide proper air circulation throughout the tomato plant. Weave the branches in and out of the trellis rungs, and use plant ties to secure larger branches for support, spreading them outwards slightly and not just straight up.
Keep an eye out for new shoots and suckers as the tomato plant matures. These mainly come from the main stem, above each leaf stem. These can eventually grow into other branches, blossom and grow to create a full tomato plant. When you see the first suckers that appear low on the plant, remove them by pinching them off with your fingers. If these continue to grow, the fruit from them will drag on the ground and become diseased. It will also encourage more suckers to grow, which you will want to leave on the plant to grow.
Water the tomato plant twice a week when the soil feels moderately dry.
Prune the plant on the trellis with sharp sterilized pruning scissors or shears. Cut away any broken or dead branches, along with any branches in crowded areas that are not flowering or seem weak. Prune the tomato plant twice a year--once in the winter and in the spring.
Use plant ties to loosely secure the tomato plant's main stem or larger branches to the trellis for support, making sure to keep all growth off the ground.