Grow 'em yourself, and you'll never eat store-bought again. Start them as indoor seeds, six to eight weeks before the last frost. Or buy them as seedlings, making sure that they're strong, healthy plants that are not in flower or fruit. Set them out in the garden when the soil is warm and the days are long. Roots will develop along the stem underground.
Space plants one to two feet apart, as they can grow four feet tall.
Encircle the stems with a paper collar to discourage cutworms. Calendula planted nearby will repel tomato worms. While it's fine to grow tomatoes with carrots, cucumbers, onions, and peppers, avoid planting it near corn, dill, or potatoes, which attract pests and stunt growth. Support plants with a tomato cage or a ring of fence and gently tie their stems to the wires. Try growing one or two plants of several different varieties in containers on a patio or a sunny balcony.