Trellising and Training Tomatoestomato plants. Some of the trellises are particularly attractive, others are surprisingly strong, and still others are rather elaborate.
Choose a system suited to the number of plants you're growing, their type, and the prevailing winds in your area. Trellises suitable only for small, determinate-type plants are noted. Otherwise, assume the trellis is for indeterminates.
Here are the ten basic ways you can train tomato plants.
Compost CagesAn ingenious American trellising method. Make a 4-foot-diameter cage (minimum) from fencing or concrete reinforcing wire. Build a compost pile inside it. The following season, plant tomatoes around the perimeter and train them to grow up the outside. Rain falling on the compost will feed the plants.
Single StakeThe most common method in the United States. Pound a solid stake a foot or two into the ground, and tie a single vine to it as it grows. Six-foot 1- x 1-inch stakes are usually set 2 to 3 feet apart, 2 feet deep, in rows 3 to 4 feet apart.
Bar-and-Twine TrellisA home-scale variation of a widely used European trellis. Sink 8-foot-tall 2 x 2 rot-resistant posts 18 inches in the ground, 5 feet apart, and join them at the top with electrical conduit flattened and drilled at the ends. Tie strings to the base of each plant with a nonslip knot, then loop over the top bar. Braid stems with the strings as the plants grow.
Dutch SpiralThis system is a high-tech single-stake method. Set the metal post 1 foot into the ground; as the pruned, single-stem tomato plant grows, it intertwines itself with the stake.
Tall Cage of Concrete Reinforcing WireAlmost as popular among American gardeners as the single-stake method, these cages are taller, sturdier versions of the basic tomato cage. Make one from 4-foot-wide concrete reinforcing wire, available at most building-supply stores. Set a stake just inside the cage and fasten the wire to it.
Long RowFor this English-style trellis, set 8-foot-tall 4 x 4s 2 feet into the ground at the ends of a 20- to 50-foot row. Run a 9-gauge wire from anchors beyond each end over the top and tighten with a turnbuckle. Run twine from the plant base to the wire or tie bamboo stakes to the wire every 2 feet, and tie the stems to grow up the twine or stakes.
A-FrameA variation on the single stake is the A-frame lean-to. Use 2 x 4s for end posts and top; 1 x 2s or 2 x 2s elsewhere. When end posts are sunk slightly in the ground, it is self-supporting. The base is 3 to 4 feet, and the vines are trained, one every 18 to 24 inches, up both sides.
QuadrapodSimilar to methods used in the Far East and the Caribbean, this system uses 3/4-inch, 8-foot bamboo stakes lashed together with twine. Set the canes 2 feet apart in every direction and then lean them together.
Quonset Hut CageCommon on Spanish farms, this system uses concrete reinforcing wire. Place hoops over the plants when they're 6 inches tall. They'll grow up through the wire grid and bear fruit on the top, away from pests. A row cover fastened over the cage at planting time makes a small grow tunnel and promotes early fruiting.
Ties That BindUse untreated twine to attach your tomatoes to the trellis. That way at the end of the season, you can simply cut the lines at the top and the tomato stems at the bottom, roll up the whole affair, and throw it on the compost pile.
Basic Tomato CagePlace these widely available funnel-shaped wire supports over plants when they're 6 inches tall; as plants grow, their branches drape over the cage, keeping fruits off the ground. Used world wide.
Tastiest TomatoesTomatoes' flavor quality is affected by the ratio of fruit to foliage. That means that the more plant there is for a given amount of fruit, the better the fruit will taste, all else being equal. The bush kinds, so loaded down with fruit on compact plants, just don't have enough flavor to go around. So if you want great-tasting tomatoes, grow only indeterminate types. And if you grow them, I recommend that you trellis them.
Convenience or Flavor?The most basic distinction among tomatoes is between the bush and vine types. Bush tomatoes are called determinate, because genetic programming causes them to grow a certain number of branches and flower clusters and then stop, much the way that peppers and eggplants grow. Because of their fixed habit, they are considerably less trouble to grow than vining or indeterminate tomatoes. They are generally earlier as well. But bush tomatoes are usually less disease-resistant, and the flavor of a bush tomato will rarely match that of fruit from the larger plants. There just isn't enough plant to produce as good a fruit.
Why Trellis Indeterminates?Indeterminate tomatoes are true vines. Being perennial they will continue to grow, sprouting new leafy and fruiting branches, until the plant is killed by disease or frost, or the growing tip is damaged or removed. I have seen 18-month-old greenhouse tomato plants fifty feet long! In long-season areas, outdoor plants trellised against the wall of a house may well climb to the roof. Trellising the plants can be a fair amount of trouble, but -- particularly if you have a small garden -- it's worth it. With a bit of attention to training the plants, you can get them to bear almost as early as the bush types. Actually, both bush and vining tomatoes should be trellised, but each kind requires a different kind of support.
Another reason to trellis -- a reason that's applicable all over the United States, but especially in humid areas of the East and Northwest -- is that it keeps the fruits and foliage off the soil, and it allows air to circulate around the plants, reducing the likelihood of foliage blights.
Trellised tomatoes are also easier to protect from pests than plants that trail on the ground. Aphids, whiteflies, hornworms, and even field mice are more visible and more easily controlled when you don't have to battle them in a tangle of ground-hugging vines.
In the Southwest, a tomato may be better off if it trails below the level of drying winds, but then irrigation is necessary, and unless you provide water through tubing rather than sprinklers, you may still see blight and mildew.
Training Indeterminate TomatoesWhatever type of trellis you choose, attach the plant to the trellis in the same way. First, tie a nonslip knot about 4 inches in diameter around the base of the plant. Then, before cutting it off the spool, run the other end of the line up and over the top of the trellis. Cut it off about 2 feet beyond the top bar, and tie this loose end with a granny knot that will come out easily later. The usefulness of this extra string will become apparent later.
Once your trellis is set up and the young plants are attached, the training begins. Training is important because it allows you to control how the plant grows, how many fruits it sets, and when.
Look closely at how a tomato vine grows. You'll see that it starts out as a single stem with leafy branches and flowering branches. But soon sprouts (sometimes called suckers) appear and grow at the stem joint (called axil) of each leafy branch. Each of these will in turn produce both leafy and flowering branches.
After each of these axial stems reaches three branches, and just before the first flowers appear on the axial stems, pinch off its growing tip to stop further development. That way, except for the axial leaves, which you want, you can keep the plant growing as a single stem. This makes it easier to trellis, and equally important, it keeps the number of fruits low in relation to the foliage, which makes for better tasting fruit. Pinch plants this way about once a week or so.
Always keep in mind that fruit flavor is related to the amount of foliage on the plants, so if you prune heavily, it makes sense to remove some of the fruits as well.
In the North (zone 5 and colder), prune consistently and carefully. But don't remove more than a third of a plant's foliage at any one time, because that may shock the plant and hamper its development.
In the South (zone 6 and warmer), don't prune plants as severely, or they'll faint in the heat and the fruits will be more susceptible to scalding by the sun.
Once you understand this basic concept, the actual training of the vine is simple. Take the slack vertical string which is loosely attached to the base of the plant, and wrap or braid it around the growing vine. Do this a minimum of once per fruit cluster. As the plants grow taller, the slack in the string disappears, and you can periodically release and re-tie the knot at the top of the trellis to make more twine available.
Once plants reach the top of the trellis, pinch out the growing point of the plant. That will cause it to stop growing and start ripening the fruit already set. And if you want early fruits, simply pinch out the end sooner. This will cause the plant to ripen fruits sooner, though overall yield will be reduced.
Trellises Mean More CareTrellised tomatoes need more water and repeated sucker pruning. We're in the cold zone 4, so we give the soil a week to warm up in the strong June sun, then lay a section of soaker hose along the center of the bed. Next, we erect the trellis and cover the entire bed with 8 to 12 inches of hay mulch to prevent rain from splashing early blight spores up onto the plants.
To avoid blossom-end rot (leathery sunken spots at the ends of the fruits caused by extreme moisture variations), water the plants regularly rather than only when they're desperate. The one exception is late in the season when the last flush of flowers has set fruit. A month before the first frost, we stop watering and remove all the too-small and too-green fruits that won't ripen before frost; this concentrates all the energy of the plant into the remaining fruits and concentrates their flavor by decreasing their water content.
Two other subtleties that affect the flavor of tomatoes are choice of variety and time of harvest. First, heirloom tomatoes, for example, have been regaining the popularity they lost over the last fifty years. The high-yielding, disease-resistant modern (often determinate) hybrids released by breeders over the past few decades, though wonders of modern genetics, just didn't taste as good as widely available, indeterminate, old-time American heirlooms like 'Brandywine' and European varieties like 'Marmande' (available from specialty seed catalogs). Second, any home gardener who picks a tomato that isn't dead ripe is wasting its taste potential. Sun-warmed and soft, that juicy vine-ripened love apple is one of the true garden treats.
Tomatoes are by far the most popular vegetable grown in American gardens. Knowing a few of the simple steps I've described here will ensure you enjoy them all the more.