Staking tomato plants is advisable for both determinate and indeterminate varieties of tomatoes. Stakes for indeterminate varieties must be longer, while shorter stakes can be used for determinate varieties, which bear fruit once per season. For best results, indeterminate varieties--which produce fruit all season--should have their suckers pruned as you stake them. This will encourage and enhance fruit growth and general plant health. Metal stakes are preferable because of their strength and longevity. If you use wood, make sure that it is not chemically treated.
Place the first stake about 3 to 4 inches from the base of the tomato plant. Pound it into the ground with the mallet.
Tie the main branch of the tomato plant securely to the stake with twine, so that the main height of the plant follows the first stake.
Form a square visually around the base of the tomato plant. Place the other three stakes at the corners of that square and pound them down with the mallet.
Tie the branches to these stakes near the highest point of each branch. Do not pull the branches or stress them. If fruit clusters have formed, make sure they do not extend beyond what you have tied to the stakes, or the weight of the growing tomatoes may cause them to break off.
Prune the suckers off the branches of indeterminate tomato plants as you stake. To do this, take each sucker between your thumb and forefinger and bend it back and forth until it comes off.