Winter squash are long season vegetables. They can take 3 months or more to fully ripen and you need to let them reach that stage if you are going to try and store them throughout the winter. Most varieties will focus on growing long, lush vines, before they begin to set flower buds and then squash fruits. Whether you are growing them on a trellis or on the ground, the vines can often grow longer than you expected.
This can mean over-crowded and heavily weighted trellises or a vegetable garden that is being completely taken over by squash plants, smothering other vegetables in its way.
Winter squash need a certain amount of vine to support and feed the developing fruits, but you don't have to let the vines grow forever. Most varieties will not set more than 4 - 5 fruits per plant. Once your vines have set that amount, you can begin to prune them back and keep them in check. While you are waiting for the fruits to set, it's fine to gently move the vines out of the way of you and your other plants.o gently move the vines out of the way of you and your other plants.
How to Prune Squash Vines
If you start pruning as soon as the 4 - 5 fruits are set, the vines should be tender enough to pinch off with your fingers. Simply look for the squash that is furthest out on the vine and pinch off the tip of the vine, leaving just a couple of leaf nodes past that final squash.
If you let the vines get unwieldy, you will need to cut more of the vine, to get back to those 1 or 2 leaf nodes beyond the final fruit. Don't worry, it won't hurt the plant. As long as the main roots of the vine are not disturbed, the plant will continue growing.
- The Vines have Rooted
When squash vines touch the soil, they can send out new roots. If the part of the vine you want to remove is near a newly rooted section, you can still lift and remove that section, roots and all. It may cause the vine near the rooted section to wilt for a day or two, but it should recover quickly.
- The Vines Grow Back
As with many plants, pruning back your squash vines once doesn't mean they won't try and grow new stems and leaves. You may have to do more pruning, to keep them confined to the space you've provided.
Options besides Pruning
If you don't have the space for the long, rambling winter squash vines, consider planting a bush variety instead. You'll have less options, but there are many good bush varieties being offered as space saving plants. You will still get about 4 - 5 fruits per plant, but they will only need about 4 sq. ft. total space. You could even grow them in containers.
Some gardeners like to use their squash vines as a living mulch. They do a good job of smothering out weeds, but use caution because they will smother any plant they grow over, including other vegetables. The vines are also scratchy and prickly, which makes them unpleasant to walk on and harvest through. This will work in your favor, deterring pests like squirrels, who don't like to walk on squash plants, but it can also be disagreeable for you.
A Pruning Bonus
Don't feel bad about pruning back your squash vines. It won't hurt the plant or fruits and it won't diminish their flavor. Pruning also signals to the plant that time is almost up for this season and it needs to get a move on toward ripening.
Since the plant won't be able to set any more fruits and you aren't letting it grow any more foliage, it can put all its energy and resources into plumping up and ripening the existing fruits.
So even if you aren't short on space, if you are inching toward the end of your growing season, you can speed things up by pruning the vines. It's the same thing we do when we prune the excess vine or pinch off late season buds from tomato plants, to get the existing green tomatoes to ripen. Prune away.
Can I Prune Summer Squash, Too?
Sure, you could prune your summer squash plants. Summer squash vines will respond the same way as winter squash. But since we harvest summer squash while it is still in its tender, immature stage, the summer squash vines will continue setting more flowers and fruits, as long as we harvest them before they have a chance to mature.
Pruning them would mean less of a harvest, unlike the winter squash plants that wouldn't set any more fruits anyway.
Eventually the summer squash vines will become exhausted and begin to decline. You can pull the whole vine out then, but hopefully you will have already succession seeded a replacement mid-season.