Tomato vines that ramble over the ground are much more likely to suffer damage from slugs, and the fruits are prone to rot wherever they touch the ground. Getting the fruit up in the sun enhances ripening, and is especially important where the season is brief.
Training systems let you fit more plants into your garden. That means higher total yields. The ideal trellis uses inexpensive, durable materials that store easily, and it's simple and quick to put up and take down.
Here are four proven designs. Shepherd Ogden, NGA's contributing editor and author of Step by Step Organic Vegetable Gardening, grows several hundred tomato pants each year in Vermont using three of these designs. The stake and weave system is favored by specialty tomato growers in the Southeast and Southwest.
Most people find it easier to erect the trellis framework after the plants are in the ground, so you can see where everything ought to go. You can, however, do the work anytime after the soil is prepared but before the plants get much more than a foot tall. Set up the trellises two to three weeks after panting, right before the mulch goes down.
Training tomato plants to bamboo quadripods is much like training them to single stakes, but the quadripods are very stable and nearly windproof. Bamboo is both very light and very strong. The ends of the canes needn't be pushed very far into the ground, which minimizes decay, and the canes can last for several seasons.
Use seven-foot by 3/4-inch bamboo canes, available at many garden centers. Set the tomato plants about two feet apart down each side of the garden bed. Stick the bamboo canes into the soil at each plant. Then, at about six feet above the ground, lash a pair of canes together with the opposing pair on the other side of the bed to make a series of quadripods down the bed.
Fasten the tomato vines to the canes with eight-inch pieces of twine, tying them at about every flower cluster. Pinch out most side shoots, and tie on any that you want to keep.
For added strength, lay bamboo canes across the top to span the row of quadripods. This greatly increases both the stability of the structure and its versatility. Run twine from the top piece to the ground and the system will work well for cucumbers, melons, pole beans, peas and nearly any other crop you want to trellis.
Commercial greenhouse growers train indeterminate tomatoes up strings. This method requires some pruning of side shoots. Shep Ogden recommends inexpensive 2x2 stakes that are eight feet long. He buys 2x4s and rips them with a power saw. After pounding them into the ground 12 to 18 inches, you'll have a stake that's six to seven feet tall. The bar across the top is made of 10-foot-long 3/4-inch electrical tubing from a building supply store. You flatten two inches on each end, then drill a hole in the center of the flattened area an inch in from the ends.
Set the stakes 10 feet apart, lay the bar on top and run one-inch galvanized sheetrock screws through the holes down into the tops of the stakes. The work goes fast. The system is very strong, and it comes apart easily in the fall.
To train tomatoes up the string, start when the plants are about a foot tall. Make a loose knot that cannot slip and become tight around the base of the stem just below a sturdy leaf or shoot. Then run the twine to the bar and and tie it loosely, leaving about two feet of extra line hanging over the top. As the tomato vine grows up, you just wrap the leading shoot around the twine, so the two are braided together. That twisting eventually uses up all the twine you left at the top. When you need slack, you loosen the knot at the top, take what you need, and tie it again. If you use untreated twine, you can cut everything out quickly in the fall and toss it on the compost pile.
If you take out all side shoots, you should space plants closely, about foot apart. It's important to leave enough foliage to protect fruit from sunscald, especially in hot, sunny regions. If you space plants 18 inches to two feet apart, you can let a few side shoots grow near the base of each plant. Tie on a string for each side shoot and start braiding the sprouts. Unsupported side shoots can tear off the main stem just as the fruits are heaviest and ready to ripen. When shoots reach the top, you top them. This trellis works well for cucumbers and pole beans, too. In Holland, gardeners grow squashes, eggplants and peppers this way.
If you've been using tomato cages, try using the same material a different way. Cages are one of the simplest and most popular training systems, but they become top-heavy as the plants mature and must be fastened to stakes to keep them from falling over in wind. Undo the cages and set them on the ground as quonsets, and the system becomes very stable. Moreover, you can let the plants sprawl with no need to tie up or clip errant side shoots. This is how some commercial tomato growers in Spain grow their plants.
Use six-inch-mesh concrete-reinforcing wire, which comes in rolls six feet wide. Cut off six-foot sections to make squares six feet on a side. This will make an arch about 18 inches tall across a 30-inch-wide bed. (To span a wider bed, the wire may need support in the center to carry the weight of a crop of tomatoes.) If you cut out the horizontal pieces along the bottom edge, you create three-inch-long pins to push into the soil. In sandy soils, you may want six-inch pins. On wooden raised beds, you may not need pins at all. Space tomatoes 18 inches apart down the center of the bed.
These tunnels (and wire cages) are excellent systems for determinate varieties. With indeterminate varieties, just drape any branches that creep into the row back over the top. The six-inch mesh is big enough to make picking simple. And the material is versatile. You can use these quonsets for cucumbers, squash and melons, as well as peppers, rangy varieties of bush beans and cut flowers. You can easily convert the wire into cages, and it can be straightened partially to stack in storage.
American tomato farmers developed this system, which is sometimes called the Florida Weave or San Diego Weave method. It uses inexpensive materials and is extremely fast to build and easy to maintain. The final effect is a dense hedge of tomato foliage. Even with indeterminate varieties, pruning can be minimal.
Set sturdy one- to two-inch stakes three or four feet apart down the center of a row or bed and at both ends. The stakes are set between plants, not beside them. If you space tomatoes 18 or 24 inches apart, you have two plants between each stake. If you like three feet between plants, put a stake between each plant. Determinate varieties will need at least three-foot-tall stakes; indeterminates require six-foot stakes.
When the plants get about a foot tall and are in danger of toppling in a wind, make the first tier of baling twine. Tie the twine to an end post and string the twine down the row alongside the tomato plants, wrapping it once around each post. Here is where the weaving comes in: A run of string between posts should alternate from one side of the tomato row to the other as you go. When you reach the end, begin working the twine back in the opposite direction, stringing it on the side opposite the path you took on your first pass. A week to 10 days later, when the vines have grown up enough to be in danger of toppling, weave another course about eight inches higher up the stake.