Bury a tomato plant's stem and the stem will sprout a slew of new roots that help the plant grow sturdy and tall quickly. You can bury just about all of stem--pluck off the branches below the top flush of leaves.
Early in the season, when the soil is still cool, dig a trench 4 or 5 inches deep in the soil and set the transplant into it, again burying the stem up to the top leaves.
If you're transplanting later in the season, when the soil has warmed or in dry climates, bury the transplant
in a straight, deep hole. Cooler, moister soil below 6 inches deep helps tomatoes survive in hot, dry summers.
Feed the soil first.
Avoid the common mistake of overfeeding your tomatoes. They thrive in soil that's rich in humus for extensive, well-nourished
root systems and potassium (K) for strong stems. Add too much nitrogen (N) and you'll have a big, lush plant with very little fruit.
"A lot of organic gardeners overload their soil with manure and get fewer tomatoes for it," notes Will Brinton, Ph.D., president of Woods End Research Laboratory in Mount Vernon, Maine. "I save my best compost for tomatoes and supplement it only with seaweed powder, which is a quick-acting source of potassium. We get incredible fruits."
Homemade compost typically supplies all the phosphorus (P) your tomatoes need for good flowering and fruiting. If a soil test indicates a serious phosphorus deficiency, add rock phosphate to your tomato-growing beds next fall.
Keep them warm, keep them cool.
Chilly spring temperatures (nights cooler than 50 degrees F) slow tomato plants' growth. Sizzling summer temps (days hotter than 95 degrees) cause the flowers to drop off. You can moderate both extremes with Wall O' Waters, which are plastic "teepees" with individual tubes filled with water. They also help keep the plants upright and shelter the plants from high winds.
Red plastic, maybe.
Many organic gardeners rely on plastic mulch to warm the soil in spring and prevent weeds from sprouting up. Plastic mulch isn't part of our ideal organic garden, but study after study has found that beds covered in black plastic in spring produce tomatoes earlier and more of them all season long. Where the growing season is short, plastic mulch may be essential if you want to harvest tomatoes at all. Even more effective, researchers have found, is infra-red transmitting plastic mulch, which reflects just the kind of light plants need up onto the foliage.