How to raise tomatoes from seed to seedlings?

Thousands of tomato (Solanum lycopersicum) varieties exist, and they can be categorized in several ways -- maturity class, fruit size, fruit color, use, and determinate or indeterminate. No matter the type, tomatoes need a sunny location and well-drained soil. Seed planting begins indoors 10 to 14 days before the last expected frost date. Starting seeds indoors then transplanting seedlings is one of the best methods for growing healthy tomatoes, because tomatoes require warm temperatures to grow and a controlled environment can be created indoors. Most varieties of tomatoes flourish in U.S. Department of Agriculture plant hardiness zones 2 to 10.

1. Fill a seed tray with clean, light potting soil. Sow a seed 1/4 inch deep in each cell of the tray. Put the tray in a room about 70 to 80 degrees Fahrenheit, and keep the soil evenly moist until germination.
2. Move seedlings to an area that has six to eight hours of sunshine per day or cool white fluorescent tubes 2 to 3 inches above them, lit for 14 to 16 hours per day. Keep the room temperature between 65 to 75 degrees Fahrenheit. Water consistently to keep the soil evenly moist, and feed the seedlings half strength soluble complete fertilizer every 10 to 15 days.
3. Prepare the garden bed when soil temperatures are above 60F and transplants have five to seven mature leaves, about six to eight weeks after planting. Spread 4 inches of well-composted organic mulch over the garden bed, and till it into the top 6 inches of soil with a garden fork or rototiller. Apply 4 to 6 cups of an all-purpose fertilizer such as 10-10-10 per 100 square feet, and mix it into the top 6 inches of the soil.
4. Harden off the seedlings 10 days before transplanting by gradually exposing them to an increasing number of hours of outdoor light and temperatures, until they can handle six hours of outdoor conditions daily.
5. Water the seedlings thoroughly a few hours and wait a few hours. Dig a hole that is about 2 inches deeper than the depth of the seedlings in the trays. Remove a seedling from the tray, handling it by the soil mass. Put the seedling in the hole.
6. Fill the hole with soil and tamp it down firmly to make a slight depression around the seedling. Space seedlings 24 to 36 inches apart and rows 4 to 5 feet apart, depending on the variety. Water the seedlings thoroughly.
7. Give the seedlings 1 to 2 inches of water per week. Side dress the seedlings with 1/2 tablespoon of nitrogen per plant four to eight weeks after transplanting.

Tips: Wooden stakes or wire cages may be installed for indeterminate tomatoes. A 3- to 4-inch layer of mulch such as compost will help maintain moisture and discourage weeds.