Sow tomato seeds indoors six weeks before your last frost date. Begin by moistening a sterile seed starting mix, such as our [a href="http://www.gardeners.com/buy/germinating-mix-with-vermiculite/03-199.html" target="_blank"]Germinating Mix[/a]. Don't use garden soil, which often drains poorly and may harbor disease organisms.Add mix to the containers. Here, we're using our [a href="http://www.gardeners.com/buy/growease-seed-starting-kit/8589987RS.html" target="_blank"]GrowEase Seed Starter[/a].Gently firm the mix to remove air pockets. Use your finger or a pencil to poke two holes per cell, each about 1/4" deep. Planting two seeds per cell increases the likelihood that at least one seed per cell will germinate.Shake some seeds into your hand … … and place one seed in each hole. Sprinkle additional mix over the cells to fill the holes and cover the seeds. Once again, gently firm the mix to eliminate air pockets, and then water lightly to ensure good seed-to-mix contact. Use a plant mister or apply a few drops of water to each cell.Place the tray in a warm place, about 70 to 75 degrees F. At this point you don't need to worry about providing light. Covering the tray helps retain moisture, which is important for germination. Check daily, taking care to keep the planting mix moist but not saturated. Once you see the first sprout, place the seedlings under grow lights, keeping the lights a few inches above the tops of the plants. Remove the greenhouse cover so air can circulate around the seedlings. This helps prevent disease problems. Keep the planting mix moist but not soggy. A self-watering seed starter makes it easy. You fill the reservoir and it delivers water to the roots when they need it.When the seedlings are about 2″ tall, it's time to thin. Choose the strongest, healthiest-looking seedling in each cell and remove the others by snipping them off at the soil line. Once the seedlings have two sets of leaves, it's time to start fertilizing. Once a week, apply a soluble fertilizer, such as [a href="http://www.gardeners.com/buy/best-fertilizer-for-container-gardening/8587940RS.html" target="_blank"]Easy Grow Fertilizer[/a].About a month after sowing, gently remove one of the seedlings and look at the roots. When the roots begin to fill the cell, it's time to repot.Each seedling gets its own container — in this case, a 4" [a href="http://www.gardeners.com/buy/self-watering-seedling-transplant-pots/17172.html" target="_blank"]Self-Watering Transplant Pot[/a].Fill the pot with moist planting mix. Unlike other types of seedlings, it's OK to bury the stem of a tomato plant — in fact, it's a good idea, because the plant will grow roots along the buried stem.Water the planting mix, and then place the seedlings back under the grow lights for a few more weeks of growth.This seedling was transplanted into a 4" [a href="http://www.gardeners.com/buy/cowpots-seedling-pots/37-034RS.html" target="_blank"]Cowpot[/a]. These biodegradable pots can be planted right in the garden.Once all danger of frost has passed, it's time to transplant your seedlings into the garden.If your seedlings are more than about a foot tall, it's best to plant them in a trench so you can bury the lower part of the stem. Begin by pinching off the lower branches and leaves. You want to avoid burying any of the foliage to prevent rot. Begin by digging a trench about 8″ deep and 6″ wide. If your tomato plant is in a biodegradable Cowpot you can plant it pot and all. Otherwise, gently remove the plant from its pot. Lay the plant on its side in the trench. Gently bend the stem so the top portion is above the soil line.Fill in the trench, firming the soil around the stem so it's upright. Water thoroughly and add a support. Here, we're using a [a href="http://www.gardeners.com/buy/tomato-cages/8587040.html" target="_blank"]Tomato Cage[/a]. Be prepared to protect the seedlings with a row cover, such as [a href="http://www.gardeners.com/buy/gardenquilt-floating-row-cover/11748.html" target="_blank"]GardenQuilt[/a], if a late cold spell threatens. Keep the plants watered and fertilized, and you'll be harvesting ripe tomatoes in about two months.