When warm weather arrives in early summer, our garden tomatoes will start to grow very fast. Once a plant is a foot or so tall, it will start to branch. As rapid growth continues, the plant flops over and grows along the ground unless it is provided with support. Left to grow horizontally, the vine will develop more and more branches, eventually becoming a tangled mess.
As noted last week, sturdy tomato cages are usually adequate support for shorter determinate tomatoes, but the taller indeterminate types need more support. This can be provided by staking each plant individually or building a trellis.
Staking individual plants involves pounding a sturdy 6- to 8-foot stake firmly into the ground 3 to 4 inches away from the plant. To avoid injuring the roots, do this within two weeks of planting in the garden and before branching begins.
When the vine is a foot tall, tie it to the stake using a soft tying material that won't cut into the stem, such as strips of nylon pantyhose, or use one of the commercial tying materials available at garden stores.
After this, pinch out any side shoots or "suckers." These side shoots develop between the base of a leaf and the main stem. A tomato plant staked and "pruned" in this way produces fewer tomatoes per vine, but the fruit that does develop will be larger. However, it makes the fruit more prone to blossom end rot and sunburn. You can try to avoid these problems by also leaving the first sucker that starts to grow above the first flower cluster that develops. Any other suckers or shoots are removed, leaving two main shoots.
If you grow more than a few tomato plants, consider building a trellis for support. The Basket Weave or Florida Weave is commonly used to trellis commercially grown tomatoes. Using this system space, your plants 18 to 24 inches apart and then place 6- to 7-foot stakes between every plant or every three plants. Use strong posts, such as a metal T or a 4-by-4-inch wooden fence post, at the ends of the row.
When plants are a foot tall, it's time to start "stringing" the trellis using nonstretching twine, such as baler's twine, or wire. Secure the twine or wire to the end post and then run it on one side of the tomatoes and fix it to the next stake. (Hint: Twine can be fixed by wrapping it around the stake.) Keeping the "string" taught, continue running it to the second stake on the opposite side of the tomatoes and fix it to the next stake.
Continue weaving the "string" in this manner until you get to the end post, fasten it to the post, then return the "string" to the beginning post by weaving it back on the opposite sides of the tomatoes, and finally fastening it to the post. Repeat the process every time the plants grow 8 to 10 inches.
To avoid dense, overcrowded vines, prune your trellised tomatoes. Leave two shoots per plant if they are spaced 2 feet apart, and three shoots if spaced 3 feet apart.
Many gardeners use their own variation of the Basket Weave or design ingenious other trellises that work for them. The key to success is a trellis that's tall enough and sturdy enough to support the vines. I think I'll try trellising my tomatoes this year.
-- Marianne C. Ophardt is a horticulturist for Washington State University Benton County Extension.