Many gardeners prefer large slicing tomatoes bursting with flavor, but often are not aware that the size and flavor of the tomato depends largely on the cultivars grown. To grow large slicing tomatoes, you must grow a variety that has been bred for size. These plants produce plump firm tomatoes most often known as beefsteak tomatoes. However, producing robust, healthy plants does contribute to tomato size, as well.
Select a variety of tomato that has been cultivated to produce large fruit that is also suited for your area. The plant identification tag provides this information. Pay close attention to the days to maturity, and match that closely to your region. Early maturing tomatoes typically produce smaller fruit while later maturity varieties grow larger.
Provide well-drained soil that is high in organic matter. Tomatoes are heavy feeders and thrive in rich friable soil. Add two to three quarts of well-rotted manure or compost the transplant hole when planting.
Grow in full sun. Tomatoes thrive in hot afternoon sun. Six to eight hours of direct sunlight produce the best tomatoes.
Transplant seedlings to the garden once nighttime temperatures remain in the 50s. Starting tomatoes in the garden during chilly weather causes transplant shock that stresses the plant. It may take weeks for the plant to recover and resume vigorous growth.
Mulch with black landscape fabric or red plastic to boost the soil temperature and control weeds.
Apply foliar feeder every 10 to 14 days throughout the growing season. Use foliar feeder labeled for tomatoes. Fertilizers high in nitrogen produce lush green growth, but reduce fruiting.
Water tomatoes weekly or when the soil dries. Soak the soil to a depth of 6 inches or more to provide the moisture tomatoes need to produce large fruit.
Prune cluster tomatoes to two or three tomatoes per cluster, once fruit has set, to allow room for large tomatoes to grow. Over-crowded fruit will not reach its optimal growth.
Remove flowers and fruit that set on late in the season, to focus the plant's energy on growing and ripening the existing fruit.