If you’re like many people (ahem, me a few years ago), you probably grow zucchini by letting it sprawl across the ground, its giant leaves going every which way.
Even with compact bush varieties of zucchini, these are not small plants. They take up a large portion of a bed, crowding out other plants and growing so densely that they sometimes end up with powdery mildew.
But what if I told you zucchini, crooknecks, pattypans, and other summer squash types don’t have to grow this way? That they can actually be staked and pruned like a tomato vine, and take up so little space that you can grow a big productive plant in just 1 square foot of soil?
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What this looks like in practice
The first time I staked and pruned my yellow zucchini, I couldn’t believe how much healthier the plant was. The stem stayed upright, the leaves grew tall, and none of the vines were dragging in the dirt and attracting diseases.
I had a manageable plant with room to grow radishes underneath the canopy and melons beside it. Best of all, growing my summer squash vertically made for easy harvesting, since I didn’t have to dive into the vines to look for fruit. (You know what happens when you turn your back on zucchini for just a minute…!)
If you’ve never tried this technique, here’s how to set it up right. (You don’t want to start too late when your plant gets more challenging to train.)
Step 1: Staking
You’ll need one (or two) sturdy 4- to 5-foot stakes to support each plant. I’ve used lightweight coated metal stakes and EMT conduit with success.
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The best time to add a stake is when you sow your seeds or transplant your seedling, as it minimizes damage to the roots.
Drive the stake 8 to 12 inches into the ground. Plant your seed or seedling right next to the stake so that as it grows, you can tie the stem to the stake.
If you already have an established zucchini plant, don’t wait! You can still train it to grow vertically. Typically I stake my plant when it’s under 1 foot tall, since it has fewer leaves to wrangle and the stem is easier to see.
Most zucchini plants have one main stem, like tomato plants. If you wait until your plant is larger, it’s trickier to find the stem when things look like this:
But, staking a mature zucchini is still doable. It’s just a bit awkward to add the stake and start training the stem, because the leaves will need some time to reorient themselves and start to grow up rather than out. Here’s what that looks like:
In my experience, I’ve found that using two stakes on either side of the stem supports it better. This really depends on the summer squash variety and your local garden conditions. (Does the bed get a lot of wind exposure?)
You can start with one stake and see if that’s enough, then add a second stake if you have trouble keeping your plant upright.
Step 2: Tying the stem
In the beginning, you might not need to tie the stem when the plant is small. You can see in the image below that I simply (and gently) wedged the main stem between two stakes.
But as the plant starts to climb and get heavier, it’ll need more support. Using a soft plant tie (like velcro, coated wire, or stretch ties), loosely tie the stem to the stake(s). You don’t want to tighten the tie so much that it restricts growth.
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Step 3: Pruning
Remove the lowest leaves at the base of the main stem. These are the oldest leaves that usually touch the soil. Use clean scissors or pruning shears to slice the leaf stem as close as possible to the main stem.
You can see how the leaf stems are hollow until they reach the main stem, where they turn solid. You want to cut the leaf right up to the main stem so you’re not leaving behind any nooks or crannies for pests to enter.
Step 4: Harvesting and continued tying and pruning
Harvest regularly to keep your plant productive. If you always let your zucchini grow to massive sizes, your plant will slow down production versus continue putting out new flowers.
As the main stem grows taller, tie it to the stake every few inches to keep it upright.
Every other week or so, continue pruning a couple of the oldest (lowest) leaves, damaged or yellowing leaves, and any leaves deep inside the plant that don’t get any sun, to improve air flow.
Make sure you don’t prune more than a third of the plant at one time. You always want to leave a good number of leaves on the plant (I aim for at least 10) since they act like solar panels, drawing energy from the sun to feed the developing fruits.
Keep pruning and tying the main stem until your plant dies back from frost (or until you get sick of zucchini or need the space for your fall crops).
How to stake multi-stemmed plants
Sometimes a zucchini plant will branch out into two (or more) main stems at the base. If you’re limited on space, simply remove one of the stems when it’s small and easy to cut.
I usually like to keep both stems, and will add a second stake to support the second stem. The plant’s footprint will be larger if you keep both stems, but still smaller than if you let the plant spread horizontally across the bed.
This particular zucchini plant started with two main stems and then developed a third stem, which I kept to let it cascade over the edge of my raised bed.
Does pruning zucchini increase yield?
According to this study, it does! But a caveat: The researchers only pruned their zucchini plants twice (at 20 days after transplanting and 30 days after transplanting) to observe the effects.
Still, even with their limited pruning, they found that “pruning helps reduce unproductive plant parts, which allows the photosynthesis process to be more widely allocated, enhancing fruit weight and production.” They also observed “increased flowering, fruit number per plant, fruit length and diameter, and ultimately increased yield compared with no pruning.”
My (unscientific) theory is that pruning may also help improve pollination (and reduce the need to hand pollinate your squash plants), since bees have easier access to flowers when they aren’t buried in multiple layers of leaves.
So give it a go! Space your zucchini plants every 12 inches to prepare for staking them, make sure the soil is rich in nutrients, and use the freed-up space underneath to grow heat-tolerant lettuce, radishes, or other short plants that benefit from some midday shade.
