The Red-Hot Rooting of Tomatoes

Everything alive strives to reproduce itself, but few do it as gleefully as the tomato. Its self-pollinating flowers generate fruits bursting with seeds well-known for their longevity. Stored in a dry place, tomato seeds stay lively longer than many of the gardeners that save them. Seeds from tomatoes tossed on the compost pile often survive and return to sprout in the garden as volunteers.

Given half a chance, tomato plants are mighty and fruitful. Perennials in the South American tropics from whence they came, their vines will extend indefinitely if not killed by frost. At our farm we once had a greenhouse so full of their rank growth that I feared it would burst in an explosion of red sauce.

Watch how eagerly a tomato plant puts down roots. Vines that are allowed to sprawl (their natural tendency) often sprout roots at the point where they touch the soil, and in damp weather you can sometimes see little bumps of root primordia forming on upright stems.

The tomato's urge to root can be put to excellent use by the gardener. It's good practice to bury part of a tomato's stem when you are transplanting it into the garden, placing the underground portion at a slant. Sturdy roots will form all along that stem. This trick is especially useful if the plants are leggy. It will keep them upright and less susceptible to wind, and if a stem does break, you can often save the plant by simply poking it into the ground to form a new root system.

A more reliable way to root a stem, however, is to plant it in the garden after you have coaxed it to form roots. You can see how easy this is just by putting a tomato stem in a glass of water. Roots form within a few days. Better yet, root the stem in a pot filled with a soil-less potting mix. Keep it out of strong sun for a few days, water it well, then plant it in the garden when roots fill the pot.

Often this technique is used to root tomato suckers, the small stems that form between a plant's main stem and a fruiting branch. Sucker pruning is done to keep the plant from becoming too heavy with vegetation and to encourage fruit production. Snip the suckers before they have had a chance to form blossoms, then root them. It's an easy way to increase your supply of plants, and because they will be clones of the original one, you can keep a hybrid variety going that otherwise would not grow true from seed. Only non-hybrid varieties, called open pollinated, breed true from saved seeds. Your goal might be to start a late summer crop, or just have replacements on hand in case an ill fate should befall your first planting -- much better than trying to hold over extra seedlings that, knowing tomatoes, might be quite overgrown by the time they're needed.