Tomatoes are probably the most popular vegetable grown by the home gardener. Success in growing good tomato transplants from seed depends on how well these basic requirements are met:
1. Disease-free soil-Use any mixture of either soil or synthetic mix that is free of disease-causing organisms. (sterilized soil, vermiculite, etc.)
2. Warmth & moisture-For fast germination, seeds need a soil temperature of 70-85°. To retain moisture, cover seed trays or pots with a plastic bag.
3. Adequate light-To promote stocky growth, once the seedlings emerge, keep them in full sunlight 12 hours a day. Daytime temperatures should be between 70-75°; nighttime between 60-65°.
4. Preparation of seedlings for transplanting-Young plants should not go directly from an indoor climate to the open garden. Expose them gradually to the conditions in your garden, bringing them in when there is danger of frost.
Tomato seeds should be sown indoors about eight weeks before the last expected frost in your area (in Montana, May 15). Sow them 1/8 inch deep in flats or pots. Making sure the soil is moist but not wet. Cover the flats or pots with plastic bags to hasten germination. When the seedlings are about 1 inch tall, transplant them into 3 or 4 inch pots. Keep them moist in a warm, sunny spot until you are ready to plant.
Better yet, Gainan’s grown seedlings can be purchased from our greenhouse, along with larger plants in pots up to 1 gallon in size ready to bear in your garden. These varieties are resistant to verticillium, fusarium wilt, and nematodes.
Preparing the Soil
Soil preparation is important for a good tomato crop. The fall before you plant, if possible, dig up your tomato plot and work it several inches deep, incorporating a 2 inch layer of compost or organic matter into the soil. In early spring rake in a 5-10-1- fertilizer (about 1 pound per 25 feet of row).
If you have not prepared the soil this way, dig a hole for each plant 6 inches deep and 2 to 3 feet in diameter. In the bottom of each hole place a 2 inch layer of compost or damp peat moss mixed with a handful of fertilizer and some of the top soil you have dug up.
Tomatoes for staking are the so-called indeterminate types. These varieties form fruit in clusters along their stems. Determinate varieties form fruit at the ends of their branches and thus are not suited for staking.
Since staked plants are growing upward rather than outward, they are forced to produce more from a given area of ground than will unstaked plants. Staking saves space, since the plants can be as little as 18 inches apart, and keeps the fruits away from dirt and slugs. A staked plant does need a healthy leaf cover to avoid sun scald on fruit, and proper nourishment (particularly calcium) and even moisture to avoid blossom-end rot.
If you plan to use stakes or trellis to conserve space, set them into the ground before planting to avoid root damage. The stake should be 1 inch square and 6-8 feet long, and made of any sturdy material (usually wood). Drive the stake into the ground about 1 foot and plant the tomato 3-5 inches from it. Train your tomato to grow as a two-stemmed plant. A two-stemmed plant will produce more tomatoes and will provide better foliage for protection of the fruit from sunburn. When training your tomato to the stake, tie it with soft twine or strips of cloth, tying once around the stake and once around the stem. This method will prevent injury to the stem, and does not restrict growth.
In order to keep staked tomatoes restricted to their desired form, the lateral buds which grow at the leaf axil (where the leaf joins the stem) should be removed when about one inch long. Use your fingers to snap them off, thus avoiding the danger of transmitting disease with the blade of a knife or shears. Once a plant reaches the top of the stake, pinch out the growing point of the shoot, and continue to remove any new leaves or flowers that form. Pinching directs a plant’s energy to the fruits that have already set, hastening their ripening and increasing their size.
Other methods of supporting tomatoes include chicken or field wire running the length of the row, staked on each end, to which the tomatoes are tied; and various tomato cages made of wire. Cages are particularly appropriate for the smaller determinate varieties which require no pruning.
Tomatoes have a wide-spread, shallow root system. Because of that, problems often occur when care is not taken in cultivation of the surrounding ground. Root damage can be done through careless cultivation that will cause wilting, poor fruit set, small fruit, and often blossom-end rot. The surface root system can also be burnt if sufficient water is not available to the plant.
When watering, remember that the root system is wide spread and water should be given to a wide area surrounding the plant as well as to the immediate area. Care should be taken to give the plants a consistent supply of water. Mulching can greatly influence the watering requirements of tomatoes. A good mulch of weed mat, straw, or hay, will reduce the amount of water lost through evaporation. At the same time, mulching will control weeds and help minimize the need for cultivation that could damage the plant’s roots.
Tomatoes will require fertilization throughout the growing season. The fertilizer you apply when preparing the soil should be sufficient to feed the plants until they begin to set fruit. At that time, and monthly thereafter, fertilize with 5-10-5. When fruit begins to mature, stop fertilizing.
Even with vigorous plants, sometimes little or no fruit develops. Causes can include inadequate water, inadequate sun, or inadequate numbers of pollinating insects. Solutions include pollinations aids such as tomato set spray, and companion planting of flowering plants which attract bees.
One excellent means of extending our short northern growing season is to use Wall O’Water plant protectors, which can extend the season 6 to 8 weeks. They heat the soil beneath the protector 10 to 15° F. and provide the plant with a very warm growing environment where it will thrive. The protectors must be set up a week before planting in a teepee configuration to warm the soil, thus avoiding transplant shock due to planting in cold soil.
Some other potential problems include:
growth cracks, caused by uneven watering
sun scald, caused by fruit being exposed to the sun’s rays through lack of leaf cover
blossom-end rot, caused by uneven watering
improper fertilization (too much nitrogen)
lack of drainage, or cultivation damage to roots
catface, caused by irregular watering and insecticide exposure
Verticillium and fusarium wilts and mosaic virus are best combated by choosing resistant varieties. They will have a ‘V’, a ‘M’, or an ‘F’ next to their names, or all three. ‘N’ means nematodes, small wormlike organisms that inhabit the soil and can injure plants. Rotating crops and removing debris is also important.
Aphids, tomato hornworms, and other insects bother tomatoes but do not usually do much damage.