Tomato seedlings show up at farmers markets and nurseries in spring, ready for planting. Planting tomato seedlings requires good soil in a prepared bed and a spot with full sun. For best root development, tomato seedlings should be planted with part of the stalk buried.
Preparing the growing area is the first step to growing tomato seedlings. Tomatoes can be grown in a sunny garden bed or in outdoor hanging baskets or patio containers. In pots or in the ground, tomato seedlings need as much sun as possible for best growth and development. A minimum of six hours of sun a day is required, with more sun providing better growing results.
Garden beds should be prepared in spring after the last frost date. A 2- to 4-inch (about 5- to 10-cm) layer of well-seasoned compost, dug into the top 8 to 10 inches (about 20 to 25 cm) of soil, can help improve the nutrient levels and soil structure for the growing season. When preparing patio pots or hanging baskets, potting soil mixed with compost can provide a rich growing environment.
Tomato seedlings can be planted as soon as the last frost date has passed. The tender, young plants are frost sensitive and can not tolerate even mild frost when planted too early in the spring. Tomatoes require 65 to 90 days of frost-free weather to mature to harvest. The length of time between planting and harvesting varies depending on the variety.
Before planting tomato seedlings, planting holes need to be dug. The holes should be slightly wider than the nursery pots and deep enough to bury the root ball and the bottom 1/3 of the stalk under the soil line. Roots grow from the tomato stalks when they are under the soil, increasing the root capacity of the plants.
Dwarf tomato plants typically are spaced 12 inches (about 30 cm) apart. Standard bush and vine varieties require a spacing of 24 to 36 inches (about 61 to 91 cm) and large heirloom varieties require spacing of 36 to 48 inches (about 91 to 122 cm). Tomato cages or stakes support vine tomato varieties during growth and fruit production.
Patio pots and hanging baskets should be at least 12 inches (about 30 cm) wide. In larger pots, several tomato seedlings can be planted together. Dwarf vine tomatoes grow well in hanging baskets.
The seedlings should be removed from the nursery pot and placed in the planting holes, with the soil refilled around each plant. Gently pressing down the soil can help secure the tomato plants in the soil environment. Plants should be watered within six hours of planting to settle the soil and minimize transplant shock.