By Adam Hill, PHS Associate Director of Community Gardens
Tomatoes, the most popular garden vegetable, grow on vines that may reach 8 feet or even taller. If left on their own, tomato plants sprawl on the ground, leaving their abundant fruit vulnerable to rotting on the soil. Gardeners have devised a variety of ways to give the vines the support they need. I recommend three tomato trellising methods, depending on the type of tomatoes and how they are being grown.
One of the most common methods of trellising for the home gardener is caging. Traditional tomato cages that many gardeners know are best for determinate (or bush) tomatoes, which top out at about 5 feet tall. Cages also work well when you’re growing in pots. Square designs are sturdier than cone-shaped models and they give you better access to the ripe tomatoes. You can also clip or tie the plant to the cage to ensure the vine is supported properly.
The stake and weave method is highly efficient for propping up tall plants in a bed or a row, and it's effective for most tomato varieties. To start, leave at least 18 inches between the seedlings when planting. Get sturdy stakes — thick bamboo or steel fence posts are good options — and nylon twine that doesn’t stretch or break down during the season.
When the plants are about 1 foot tall, drive in a stake at each end of the row. Then add a stake after every 2 plants. Starting about 8 inches above the ground, tie a length of twine around the first stake and weave the twine along one side of the plants, looping around each stake as you go. When you reach the last stake, loop the twine around the stake and pull it taut, taking care to not damage the plants’ stems. Then weave the twine along the other side of the plants to sandwich them between the 2 strings.
As the plants grow taller, weave additional lines of twine about every 6 to 8 inches up the stakes. You should also prune your tomato plants so that they have at most two or three main stems. This allows air to flow around them, which reduces the risk of fungal diseases on the leaves and fruit.
Vertical trellising is my preferred method for growing tomatoes. To hold up rows of vines from the tallest (indeterminate) varieties, you can use hanging strings to create a vertical trellis. Start by driving in sturdy 8-foot-tall wooden or steel posts at each end of the row and every 6 to 8 feet between them. Thread high-tensile wire, stretched tightly, through holes drilled in the tops of the posts.
Alternatively, you can build a simple frame from ¾” electrical conduit. Tie twine to the wire or frame at every point where a tomato vine is growing — the twine should be long enough to curl around the base of each plant. I like to use tomato roller hooks which have a spool of twine that is attached to a hook that hangs on the top wire. I would also recommend plastic tomato clips (a box of 1,000 costs about $20 and they can be reused from one season to the next) to connect the stems to the twine without damaging the plants. With this method, you need to prune each plant to leave just one stem. This method requires a bit more setup and ongoing pruning, but you’ll be rewarded with healthy plants and the highest quality fruit.
Producing a delicious, bountiful harvest of tomatoes each season doesn’t have to be complicated. However, because tomato vines are delicate and require support to grow properly and efficiently, it is important to adopt the right method of trellising for your type of plant and continue to regularly maintain your plants and trellis method as the plants grow. With these three methods in mind, you’ll be more prepared for a successful growing season and healthy, thriving tomato plants.