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.

Watermelon vine tied to a trellis

I like to tie up the vines at the base of a leaf axil. I use a loose figure-8 to attach them to the trellis.

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.

Side shoots from a watermelon plant

These are side shoots, growing out from a leaf axil. I prune them all off, leaving only the main vines to grow up the trellis. If I don't, the trellis gets quickly overgrown. You can also see a baby watermelon growing in the corner of the cinder blocks.

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

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Leave a Reply 11 comments

Nancy Beazel - June 17, 2014 Reply

This is the most helpful article I have found regarding this subject. Thank you.

Jon Lewis - August 31, 2014 Reply

I have had horrible experiences in the past with container gardening in the past but this year decided on raised beds using Mel’s recommendations. I was shocked at how well some things grew, completely overwhelming the trellis system I put in place. After seeing your website and reading your information on trellis construction I now have upgraded to livestock panels with t-posts 🙂 A huge improvement the home improvement store specials I was using.

Thanks

    Debra - September 1, 2014 Reply

    You’re welcome, Jon! I’m so glad your garden is doing so well that you’ve had to upgrade your trellis! 🙂

Theresa Verver - February 17, 2015 Reply

Debra, I’m enjoying your comments on vertical gardening. I have already invested in veggie cages and will look to see how I can adapt. . If you have any ideas of what I can do to improve my fortunes, as a Canadian in the Ottawa Valley, I would really appreciate it. Thank you and I do enjoy your blogs…

    Debra - February 17, 2015 Reply

    Hi, Theresa! Good to hear from you. As you garden in a cold climate very different from mine, you might want to reference northern gardener books, such as The Vegetable Gardener’s Bible, The Year-Round Vegetable Gardener, and Four Season Harvest. Since your warm-season crops may have difficulty ripening in your cool summers, look for varieties bred to tolerate cooler weather. You could grow them inside a hoop house or under row cover for extra warmth (but uncover the plants during the day that need bees to pollinate their blossoms – such as squash or melons). If you start your trellised crops inside cages, you could cover the cages in row cover until the plants get larger. You also might not want to use organic mulch in your garden during the growing season, as it could keep your soil too cool. Also, raised beds will warm up better for you. Best wishes with your garden this year!

Steve Simpkins - February 19, 2015 Reply

I am planning on putting 2 trellis in a 4×4 box for squash and another for tomatoes. Where in the box do you put the 2 trellis?

Steve

    Debra - February 19, 2015 Reply

    Hi Steve! I put them on the north and south sides of the garden bed. This way, they don’t shade each other as the sun travels high overhead in the summer.

Deitra - February 19, 2015 Reply

Hi, I get why plants need to be pruned and cut but can the parts of the plant that are cut off be replanted in another location on a different trellis?

    Debra - February 19, 2015 Reply

    Hi Deitra! The only plant I can think of that you can do that with would be tomatoes. Give the tomatoes cuttings some shade and frequent watering until they form roots and start growing. Not sure the cuttings would survive in extreme summer heat, though. Good luck!

Belinda Peck - April 12, 2015 Reply

Hi Debra, my husband found your page while looking for info on going watermelons on trellis. He found you! I enjoyed reading all your pages, great simple to read information and great photos. I hope my watermelons and all the other vegs we are going to try grow well this year. By the way, we are living in the Amazon jungle in Peru. The climate can be brutal and the sun is very strong. We are finding most, maybe all, plants that tolerate fun sun still suffer our suns intensity and find we still must offer some form a shade during the mid afternoons. Just wanted to say Hi and thanks from the Amazon! Best regards and happy gardening. 🙂

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