Tomatoes are a mainstay in most summer gardens. Delicious in warm-weather salads, they are also essential to many cooked dishes. And the plants require far less water to grow than many other vegetables. Here are some tips to help ensure a successful harvest.
Wait to plant until all danger of frost is past and the soil is sufficiently warm. Cool weather makes tomato plants more susceptible to diseases and pests and slows plant growth.
Prior to planting, “harden off” tomato seedlings by placing them outside for about a week. Put them in a sheltered location, and then gradually expose them to garden conditions. If frost threatens, bring the plants indoors or cover them.
Choose stocky transplants six to eight inches tall with healthy green leaves. Check the bottom of the container. If roots are growing out the bottom, the seedlings may have been in the pot too long and may be root bound.
Water seedlings a few hours before planting and make sure the soil in the planting area is moist. Pinch off all but the top two sets of leaves. Carefully remove each seedling from its plastic pot without handling the fragile stem. Loosen the roots. Set the seedling in a planting hole deep enough to cover the exposed stem when the hole is backfilled. Those little hairs on the stem will form roots if buried and will help give your plant a good foundation.
If the seedlings are in biodegradable pots, you can plant them in the pot, but break up the pots slightly so the roots can easily grow into the soil.
Fill the planting hole with soil, press the soil firmly around the plant, and then water the area thoroughly.
Tomatoes need full sun and plenty of room to grow. If planting in a pot, choose a large one. If planting in the ground or in raised beds, space seedlings 24 to 30 inches apart. If you don't intend to stake or cage them, they will need even more room.
Most tomato plants benefit from some type of support. Cages or stakes keep them off the ground, maximize space and make harvesting easier. I like the rectangular wire cages that collapse for winter storage.
Place cages around seedlings soon after planting to avoid damaging the plants. Insert two strong stakes on both sides of the cage to provide support when the plant becomes heavy with fruit. Check the ultimate height of the variety you are planting to determine the height of the cage you need. The openings in the cage should be large enough to accommodate your hand at harvest time.
If you prefer to stake your plants, select stakes six feet long and one and one half to two inches wide. Drive them one foot into the soil four to six inches from the plant. As the plants grow, pull the stems toward the stakes and loosely tie them at intervals of ten to twelve inches. Use strips of cloth or other flexible material. Prune the plants to a few main stems to keep them from becoming too heavy.
Tomatoes need regular watering. Fluctuations in soil moisture can promote fruit cracking and blossom-end rot. Keep the area weeded. Weeds compete with your tomatoes for nutrients and water and can harbor pests. A three- to four-inch layer of mulch will minimize weeds and help retain soil moisture.
Don't fertilize until the plants are flowering and fruits are forming. Too much nitrogen fertilizer in the beginning will encourage green growth but will delay fruit formation. Once the plants start fruiting, give them a nitrogen fertilizer every four to six weeks. Follow the instructions on the label. Place the fertilizer alongside the growing plants in shallow grooves or on the soil surface. Water it in thoroughly.
Harvest tomatoes when they reach full color. Store at room temperature—not in the refrigerator—to enjoy their flavor at its best.
Tomato Plant Sale: U. C. Master Gardeners of Napa County will hold their fourth annual Tomato Sale and Education Day on Saturday, April 23, from 9 a.m. until sold out, in a new location at 1710 Soscol Avenue, Napa. Choose from 28 varieties, including heirlooms and new varieties in a range of colors. These healthy, Master Gardener-grown seedlings include types for fresh eating and for sauce.
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.