Soil. Tomatoes prefer rich, well-drained soil that is slightly acid (pH 6.4 to 6.8). For containers, mix three parts potting mix with one part good garden loam.
Spacing. Crowded plants are more likely to succumb to fungal diseases. Space tomatoes at least 2 feet apart so air can circulate around the plants and dry the foliage.
Water. Tomatoes need about an inch of water weekly, or up to 2 inches during the hottest weather. Irrigation water should be directed at the soil and not splashed onto leaves. Keeping a steady moisture level—neither too dry nor waterlogged—can reduce cracking of ripening fruits.
Mulch. A layer of straw or other organic mulch helps maintain soil moisture and prevents weeds from popping up. Mulching helps control blossom-end rot, a calcium deficiency that is exacerbated by fluctuations in soil moisture. By preventing disease spores from splashing onto lower leaves, mulch can also reduce soilborne diseases.
Fertilizer. Specialized fertilizer formulations, such as Espoma Tomato-tone, blend nutrients tomatoes need for fruit production with a limited amount of nitrogen. Don’t overfertilize, because too much nitrogen prompts rapid leaf growth at the expense of fruits.
Crop rotation. Relocate your tomato bed every year to stay a step ahead of soilborne diseases and pests. Select a garden location where tomatoes and other nightshade-family crops (peppers, eggplants, potatoes, ground cherries) have not grown in 3 or more years.
Fall cleanup. After frost, pull the plants up by the roots and rake up any fallen leaves and fruits. Plants that stayed healthy can be composted, but if there were any signs of disease, keep the plants out of your compost pile.
Photo: Patrick Montero
Originally published in Organic Gardening magazine, April/May 2014