Tomatoes are sensitive to cold temperatures, so wait until all danger of frost has passed to set out your plants. (Or provide frost protection on chilly nights.) When you're ready to plant tomato seedlings into your garden, follow these steps. Pinch off the bottom leaves, retaining the leaves at the top of the plant. Remove the plant from its pot, handling it by the base of the stem. Dig a trench deep enough to completely cover the root ball. Sprinkle a little slow-release fertilizer or tomato food into the trench, if you like. Lay the tomato on its side in the trench, gently bending up the top of the stem as you rake soil around it. Firm the soil around the roots and the lower part of the stem. (Because a tomato can grow roots from its stem, bury most of it for a stronger, more stable plant.) Soak with a gentle sprinkle, not a blast from a hose. Re-cover any roots exposed by watering. Mulch with dried grass clippings, straw, newspapers or plastic garden film. Put a tomato cage in place, if you have one. You can add it later, but don't wait too long. Tomatoes grow quickly!