Set out your tomato seedlings when nighttime temperatures are fairly sure to remain above 55°F (13°C). Seedlings should be spaced 2 feet (60 cm) apart for early tomatoes and 3 feet (90 cm) apart for main-season types, in rows at least 3 feet (90 cm) apart. Alternatively, plant the seedlings in holes prepared as described above.
Set each plant deeply in the ground, burying most of the stem; the stem will produce roots and anchor the plant firmly. Plant tall, lanky seedlings on their sides, placing the entire stem up to the top leaves underground.
Immediately after planting, do the following: Give the seedlings a boost with a cupful of compost tea; naturally protect each plant with a cutworm collar, which you can make by removing the bottom from a paper cup, and set the collar into the soil; listen for cold-weather warnings, and if a late frost seems imminent, cover the plants at night.
If you do not organically enrich the soil before planting, feed tomatoes weekly by spraying foliage with a seaweed solution.
Cover the ground with a thick mulch of grass clippings mixed with straw or chopped leaves to help keep the soil moist and prevent weed growth.
To keep indeterminate plants from making too much leafy growth, prune them to a single main stem by breaking off side shoots when they appear. You will notice these side “suckers” growing between the main stem and the leaf stem. And if you see additional suckers growing from the base of the stem, remove them too.
Tomato plants need at least 1.2 inches (3 cm) of water per week; so water them well, especially during dry spells. Continue looking for and eliminating sucker growth and tying staked tomatoes as they grow taller.