Planting & Spacing
Planting dates for eggplants, peppers, and tomatoes in Utah vary depending local climate conditions and range from early April in southern Utah to mid-May in northern Utah. Planting is recommended after danger of frost has passed (Fig. 9.3). Information on local freeze dates can be accessed through the Utah Climate Center (climate.usurf.usu.edu). Eggplants, peppers, and tomatoes grow best when daytime temperatures are 75 to 85°F and when night temperatures stay above 60 to 65°F (eggplant and pepper) or 50°F (tomato). Temperatures above 95°F may result in flower bud drop and pollen death.
Fig. 9.3. Tomato transplants are planted after frost has passed
Space plants 18 to 24 inches apart in the row, with 3 to 4 feet between rows.
Space plants 12 to 18 inches apart in the row with approximately 15 inches between rows, with two rows per 30 inch bed. Beds can be spaced on 36 to 42 inches from center to center, leaving 6 to 12 inches between beds. Paired rows help reduce sunscald. This supports a plant population of 16,000-29,000 plants/acre (Fig. 9.4). Plan road ways within the field for more convenient access during harvest. Transplants should be set so the soil level reaches the cotyledon leaves or the first true leaf. Plants placed at these depths grow larger and produce more leaves. Total fruit weight has been shown to be 26% higher on plants set to cover the cotyledons than on plants set to cover just the top of the root ball (Vavrina et al. 1994).
Fig. 9.4. Pepper spacing ensures adequate light and nutrients
Space plants 18 to 24 inches apart in the row and space rows 36 to 48 inches apart depending on the variety. Indeterminate varieties will need more space than determinate varieties. The stem of a tomato transplant may be buried in soil up to the first leaves (or more if the plant is spindly) since tomato plants produce adventitious roots on buried stem tissue.