Many gardeners start tomato seeds indoors early in the spring so that the tomato plants get off to a good start before being put in the garden. As soon as all chances of frost have passed in your area, you can transplant the young tomato plants in the garden, regardless of their size. The key is to remember to space them properly so that they will have plenty of room to grow and produce fruit.
Prepare the garden space by deeply tilling the soil to a depth of 6 to 8 inches. Add 1 to 2 inches of organic compost to the top of the tilled soil and re-till the area to distribute the compost throughout.
Lay out black plastic mulch over the area where you plan to plant tomatoes. Use large rocks or stakes to hold the mulch in place. Black plastic mulch is inexpensive and available at most garden centers. It comes in long rolls, approximately four feet wide and up to 100 feet long. This will prevent weed growth around the tomato plants.
Use scissors or a razor knife to make large "X"-shaped cuts into the mulch fabric. Each cut should be 6 inches to 8 inches in length. For smaller varieties of tomatoes, these cuts can be spaced at 12 inches apart. For larger varieties of tomatoes, make the cuts 18 inches apart.
Use a garden spade to dig a hole in the center of each "X" cut in the mulch. The hole should be only slightly larger than the container growing the young tomato plant. For instance, if the transplant is in a 2 inch peat pot, you would dig a hole approximate 2 1/4 inches wide and 2 1/4 inches deep.
Remove the transplant from the container by gently holding the plant stem in loosely between the fingers on one hand and tipping the container upside down. If your young transplants are in peat pots this step is not necessary.
Place the young transplant in the center of the hole. Fill in around the roots of the plant with the dirt you removed from the hole.
Water the plants gently until the soil around the transplants is thoroughly soaked.