Large tubs or pots filled with enriched potting soil work well, too. Dig it under and into the soil before planting, as phosphorus is not an element that leaches downward. That way, when the young plants are 3 inches high, you can bury them deep in the garden up to the top set of leaves. Remember, the more roots, the more nourishment each plant will get. Fluctuations in soil temperature and moisture are the leading cause of blossom end rot, a black fungus that grows on the blossom end of tomatoes.
Consistency is key.
A slow hose laid at the base of each plant to deliver about an inch a week is best and keeps the leaves dry, reducing fungus problems. Cut back on water, though, a week or two before harvest for best-tasting fruit. It's best to build your own sturdy tomato cage or trellis out of wood.