Training and Pruning Trellised Vegetables

Using trellises in your vegetable garden is a great way to harvest a large amount of food from a small area. But your success can depend upon selecting the right trellis, and properly training and pruning your plants.

You can trellis a wide variety of vegetables, such as watermelons, cantaloupe, squash, cucumbers, tomatoes, peas, and beans. I’ve even heard of someone trellising sweet potato vines, though I generally prefer to grow the bush varieties.

Select A Suitable Trellis

First, select a trellis that suits the plants you want to grow. There are many different types of trellises:

• nylon string mesh tied between metal poles
• bamboo poles
• 2” x 4” welded wire nailed to wooden supports
• twine wrapped between supports
• livestock panels secured to t-posts
• commercial trellises
• small tree branches, and more.

Deciding which kind of trellis to use can depend upon what vegetable crop you want to grow on it.

1) Wrapping Vines

Some plants will climb the trellises themselves, with little help needed from you, if the trellis is well suited for them. Pole beans will wrap their vines around vertical supports. However, I’ve found that if the trellis has small holes (such as the 2” x 4” welded wire fence), these plants don’t have the room to swing their vines around to grab the vertical supports. They seem to do fine, though, if the trellis has at least 6” x 6” spacings.

2) Vines with Tendrils

Other plants use tendrils to cling to the trellis. Don’t count on tendrils alone to support plants that carry heavy fruit, such as butternut squash. You can weave the vines back and forth through the trellis to provide extra support (if the holes are large enough) – but be careful you don’t damage or break the vine.

Don’t worry too much if you do, though, as most plants will soon send out another vine you can use to replace it. It will just take more time for the plant to reach full size. You can also tie the vines to the trellis, instead of weaving them. I do a little of both.

I tend to plant my climbing snap peas too densely – a bad habit I have a problem breaking. Normally, peas can support themselves pretty well with their tendrils to any trellis with small wires or string – though they may have problems gripping the trellis if you are using thicker pieces of branches, wood, or bamboo poles, as their tendrils are fairly small.

But if they are too crowded, these plants tend to billow away from the trellis. They try to cling to each other, but these insecure vines are often blown down with strong winds. In this case, I tie them back to the trellis with some twine – but I’d be better off not planting them so thickly!

3) Unsecured Vines

Tomatoes and sweet potatoes have no way to hold onto a trellis. You will need to tie them up.

Select a Strong Enough Trellis

Make sure the trellis is secure and strong enough to support the weight of your crop. I often have 20-30 pounds of fruit hanging from the trellis, and that doesn’t count the weight of the vines. If a strong wind comes through, it can put a lot of force on a trellis. I once found a trellis that had been blown flat to the ground from a storm.

Training and Pruning Your Plants

Most large vining plants, such as squash and tomatoes, send out new vines/shoots at the base of nearly every leaf. If you let all of these grow, you can end up with a huge, tangled mess overwhelming your trellis. Near the base of the trellis, I select several main vines from each plant to train up – usually about 1 vine for every 6 inches or so of trellis width.

Your goal is to fill the trellis with plant growth, but to allow most leaves to have access to full sunlight. If the trellis gets too crowded, many of the leaves won’t receive enough sunlight to thrive. It also reduces the healthy circulation of air, which could increase disease outbreaks.

Once I have enough main vines climbing my trellis, I then prune off most of the side shoots. You will get plenty of fruit on the main vines. There is one thing you need to be very careful about when cutting off extra shoots/vines. It’s easy to accidentally cut a main vine instead of the side one – so be sure to double-check before you cut! Been there, done that…this summer, in fact.

I usually train and prune each trellis at least once every week when the vines are growing fast. I tie up any vines that need assistance in climbing, save and train any new shoots I need to help fill the trellis, and then prune off any side shoots that would over-crowd the trellis.

My plants are often so vigorous that they grow taller than my 7 foot trellises. I can’t work on anything more than about 6 feet tall, so the long vines start dangling down from the top. If they start shading the rest of the plant, I’ll usually cut them back, too.

Trellising is a great way to increase the amount of food you can harvest from small gardens, as long as you select a suitable trellis and train and prune your plants well.

You, too, can feast year-round from your small backyard!

~ Debra