by Ken Lain, The Mountain Gardener
With so many tomato varieties and uses in the kitchen, it’s no wonder tomatoes are one of our most popular vegetables! It’s time to start tomatoes by seed for garden planting the end of April.
When to start tomatoes — Start tomatoes indoors 4 to 6 weeks before the average last spring frost of May 8. Transplant your seedlings into the gardens when nighttime temperatures are at least 45°F and soil temperature is ideally 70 to 90°F degrees.
Containers — Use shallow, sterile containers with drainage (use 6-pack trays or peat pots). Transplant into larger, 3- to 4-inch containers once the true, scalloped leaves have emerged. Biodegradable paperboard pots are the ideal size, easy to label and easy to share with friends.
Seed starting mix — Use a lightweight seed starting potting soil, and sow seeds at a shallow, 1/8- to ¼-inch depth. Watters seed-starting soil is sterile (unlike garden soil) and lighter than potting mix, allowing for the ideal air-to-moisture ratio.
Transplanting and supporting — When transplanting seedlings outside, plant them deeply, burying the stem leaving 1 to 2 sets of leaves above ground. The buried parts of the stem will sprout roots and develop a strong, extensive root system.
The top of the seedling above ground will naturally reach toward the sun. Place any stakes, cages or other type of supports in the ground just after transplanting to avoid root damage.
Growing temperature — Temperatures above 55°F at night are required to set fruit. Night temperatures above 75°F in the summer inhibit fruit set and can cause blossom drop (no fruit production). Wait until night temperatures are at least 45°F before transplanting.
Water — Tomatoes need about 1 to 2 inches of water per week depending on the type of soil they are growing in. One to two deep soakings per week in mild weather, and 2 to 3 per week in hot weather should be sufficient.
If tomatoes are cracking, back off on the water. Too much water can burst tomatoes and water down the flavor.
Harvesting — Each variety is different when it comes to color. Check your seed packet to see when the tomato has ripened with the best flavor.
Tomatoes are grouped into two main types according to growth habit and production.
• Determinate types (e.g., Ace 55, Glacier, Italian Roma) grow in a compact, bush form, requiring little or no staking. Fruit is produced on the ends of the branches; most of the crop ripens at the same time. One or more successive plantings will ensure an extended harvest period. Determinate types are often the choice of those who want a large supply of ripe fruit at once for canning.
• Indeterminate types (e.g., Better Bush, Sun Gold, Black Krim) varieties continue to grow and produce fruit through the end of October. Tomatoes in all stages of development may be on the plants at one time. The plants set fruit clusters along a vining stem, which grows vigorously and long.
Under optimum conditions, some can grow over 15 feet, but in most home gardens they generally reach about 6 feet. Some indeterminate have a bush form with stockier vines, which set fruit clusters closer together.
• Semi-determinate types (e.g., Lizzano) grow in between these two types. The plants will grow larger than determinate varieties, but not as large as indeterminate. They produce a main crop that ripens at once, but also continues to produce through October.