Insider Secrets to Growing Tomatoes

It’s time to start tomatoes by seed for garden planting the end of April.

by Ken Lain, The Mountain Gardener, Watters Garden Center

When to start Start tomatoes indoors four to six weeks before the average last spring frost May 8. Transplant seedlings when nighttime temperatures are at least 45°F and soil temperature is 70-90°F degrees.

Containers Use shallow, sterile containers with drainage (use six-pack trays or peat pots). Transplant into larger, 3-4” inch containers once the scalloped leaves have emerged.

Seed-starting mix Use a lightweight seed-starting potting soil; sow seeds at a shallow, 1/8-1/4” inch depth. Watters’ seed-starting soil is sterile and allows for ideal air-to-moisture ratio.

Transplanting, supporting When transplanting seedlings outside, plant them deeply, burying the stem leaving one to two sets of leaves above ground. The buried parts of the stem will sprout roots and develop a strong, extensive root system. 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. Wait until night temperatures are at least 45°F before transplanting.

Water Tomatoes need about 1-2” inches of water per week depending on type of soil; one to two deep soakings per week in mild weather; two to three per week in hot weather.

Harvesting Check seed packet to see when the tomato has ripened with the best flavor.

Types Tomatoes are grouped into 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 ripen at the same time. One or more successive plantings ensures an extended harvest period to yield a large supply at once for canning.
    • indeterminate types (e.g., Better Bush, Sun Gold, Black Krim) continue to grow and produce fruit through October. Tomatoes in all stages of development may be on the plants at one time.
    • semi-determinate types (e.g., Lizzano) grow in size between these above two types. They produce a main crop that ripens at once but also continues to produce through October.

Photos: Watters Garden Center