Grow Your Own Summer Squash

Squash is native to North America and comes from the cucurbit family, alongside cucumbers, pumpkins, gourds, and melons. There are hundreds of squash varieties out there, so we're going to focus on summer squash today (think zucchini and your standard yellow squash).

Some winter squash types grow best on a trellis, but summer squash spreads out wide and doesn't need a trellis to climb. My plants grew at least 4 feet wide last summer and took over my garden pathways.

Squash requires full sun, consistent water, and soil with a lot of nutrients to help it produce fruit. 

Here's your buyer beware if you're considering growing squash in your garden: it sometimes feels like everything's out to get your squash. Pests. Disease. Pests. Did I say pests?

If you like a challenge or if you really love squash, then here's how to plant and tend your squash, plus tips on troubleshooting common squash problems.

Summer Squash Types to Grow in Your Garden

There are many different types of summer squash. You can grow squash shaped like a club, like a globe, or like a little disc with a scalloped edge.

Here are some of the most well-known summer squash types:

Straightneck Squash

This is your classic yellow squash, with bumpy skin and pale white flesh. It's often used in casseroles and vegetable medleys.

Crookneck Squash

This is your standard yellow squash but with an extremely tapered and curved body. It tends to have thicker, waxier skin and larger seeds and is typically harvested when it's more mature.

Green zucchini

This is the classic green vegetable with thin skin and a mild flavor. Zucchini can be grilled, sautéed, added to baked goods like breads, and even used as a substitute for pasta (zoodles).

Yellow Zucchini

This one looks a lot like classic yellow squash, but you'll notice there's no tapering at the neck. Compared to green zucchini, yellow zucchini is a bit sweeter.

Round Zucchini

Also called eight ball squash, this one has globe-shaped fruits with a mild zucchini flavor.

Pattypan Squash

And the award for the most adorable squash goes to the ones shaped like flying saucers. They come in yellow, green, and white and have characteristic scalloped edges. Their skin makes them nice and crunchy.

Zephyr Squash

This two-tone fruit (yellow on top, green on bottom) is a hybrid between summer squash and two types of winter squash. You can use it as you would yellow squash.

Is Squash a Fruit or Vegetable?

Squash is, botanically speaking, a fruit, but just like tomatoes and peppers, it's often called a vegetable because it's not sweet.

If you plan to grow squash, it's helpful to think of it as a fruiting plant to set your expectations for things like fertilization needs, tending needs, and time to harvest. Fruiting plants tend to be needier than vegetables like leafy greens and root crops.

Where to Grow Squash & Zucchini

Zucchini and squash are two plants that tend to take up the most horizontal space in the garden. It’s for this reason that I often plant these outside my raised beds, in more of a row-garden style. These plants need a minimum of one full square foot, though they prefer more like two to three square feet per plant. 

If you're looking to expand your current garden setup, you can set up your own squash patch by sheet mulching right on top of your lawn.

You can also grow squash in your raised beds if you prefer. I recommend planting them on the edge of your raised beds so that you can train them to grow over the sides. That way, they'll take up less actual raised bed space but still benefit from the extra depth for their roots. You'll have to prune diligently, though, or they'll spread wide and take up your whole raised bed.

In the ground or in a raised bed, just make sure your squash plants get full sun. They'll grow with 6 hours of sunlight a day, but they'll be much more productive with closer to 8.

The Best Companion Plants for Squash

If you're growing squash in raised beds, I recommend spreading your squash plants out throughout your garden and interplanting them with lots of beneficial companion plants, like herbs and flowers. Marigolds and nasturtiums, for example, both help to repel squash bugs and attract beneficial insects that might take care of pest issues for you. Sage is said to deter squash vine borers, and thyme repels aphids.

When to Grow Squash & Zucchini

Squash and its cousins in the cucurbit family are a warm season bunch. They love temps in the 70s and 80s. Anything over 90°F, however, starts getting a little too hot for summer squash.

Squash have zero frost tolerance. Don't even think about planting squash until all threat of frost has passed in your area. I usually plant about a week or two after my last frost date so that the soil has had plenty of time to warm up a bit.

If you live in a colder climate, the summer months will be your prime squash growing time. For those of you in a warmer climate, you might do best growing your squash in the late spring and fall, with a break during the hottest summer months.

How to Plant Squash

Cucurbits don't like being moved, so direct sow your squash once the weather is right for best results. I'd only start squash by seed indoors if you have a really short warm season. If that's the case, I'd start seeds in biodegradable pots so that you can plant them in the garden without having to handle those sensitive squash roots.

If you're planting squash in the ground, then you'll make little hills of compost-amended soil or pure compost, spaced every 3 to 4 feet apart. Plant one to three squash seeds per hill, at a depth of ½ to 1 inch.

You don't need to create a hill in a raised bed, but I would add a 2- to 3-inch-thick layer of compost to the surface of the soil to give your squash seedlings a nice little nutrient boost after germination.

Keep the soil moist until you see sprouts appear, which typically takes about 5 to 10 days. Thin to 1 plant per mound or spot in your raised bed.

How to Water Squash Plants

Squash plants need about 1 inch of water a week. I recommend one to two deep waterings per week once your plant is established instead of several shallow waterings. Yellow leaves are usually a sign you're over- or under-watering your squash.

The best time to water your squash plants is in the morning. Avoid evening watering and splashing water on the leaves so that you're not creating an environment that's conducive to powdery mildew development (more on that in a bit).

If you don't already have an irrigation system installed, consider setting up an automated drip irrigation system. Not only does drip irrigation give plants the deep watering they prefer, it also keeps the foliage dry.

How to Fertilize Squash Plants

My favorite way to fertilize squash is just by applying a layer of organic compost around the base of each plant. Compost adds key nutrients, helps maintain soil moisture, prevents splashing of fungal spores up onto the leaves, and regulates soil temperature.

Once your plant is flowering, you may want to add more nutrients to support fruit production. The key nutrient to focus on at this point is phosphorus. I typically add phosphorus with bone meal, fish emulsion, or rock phosphate, but you could always do an organic liquid fertilizer or granular mixture. Diluting liquid fertilizer and spraying the leaves is a great way to ensure fast absorption. Side-dressing the plant with granules means slower absorption but less risk of over-feeding your plant.

If you notice too many male flowers on your plant, your soil might have a calcium deficiency. You might need to add an organic source of calcium like gypsum.

How to Prune Squash

Pruning squash regularly is especially important if you're growing in a raised bed so that your plant doesn't take over. Pruning also increases air circulation, deters pests and disease, and can even maximize your fruit production. That's because removing extra foliage frees up the plant's energy to put toward flowering and fruiting. The plants I prune the heaviest are always the biggest producers.

Prune your squash weekly, starting as soon as the first flower forms, with a clean pair of pruners. First, remove any damaged or yellowed leaves. Then, starting at the base of the plant, look for non-flowering stems. These stems will be thicker cylinders with large leaves at the end, and when you cut them, you'll notice they're hollow. Cut as close to the main stem as possible. Remove 2 to 3 of these stems every week, especially ones that are touching the soil to help prevent pests.

After a couple weeks of pruning, your plant will likely start producing flowers closer to the center of the plant, rather than the outside, which is what you want.

By the way, you might want to wear gloves and long sleeves when you're handling a squash plant. The stems are actually covered in little bristles that can irritate your skin.

How to Support Squash Plants

Even though squash and zucchini plants don't need a structure to climb, they benefit from a little support to keep them upright. Use stakes and twine to hold stems and leaves off the soil, if needed.

How to Protect Squash from Pests

Squash plants are like a magnet for pests. There are squash vine borers, squash bugs, aphids, cucumber beetles, and more.

In addition to planting the herbs I mentioned around your squash, there are a couple measures you can take to prevent squash pests.

First, make sure to keep the soil area around your squash clean. Mulch, straw, and leaf debris give pests a place to hide.

Two, consider covering your plants with garden mesh or row covers from the day of planting to keep flying pests out. You'll only lift this cover to tend your plants, and then you'll remove it during the day once your plants are flowering so that pollinators can access them. The moths that lay squash vine borer eggs are, unfortunately, active during the day, but they may have already found somewhere else to lay their eggs for the season.

Three, check the leaves and stems of your plants every day. Squash vine borer and squash bug eggs look pretty similar—they're both small, reddish-brown dots. Squash vine borer eggs tend to be scattered all over the plant (they're pretty good at hiding), while squash bug eggs are usually clustered. Knock any eggs you find off the plant. Remove squash bugs and cucumber beetles by hand and drop them into soapy water.

Finally, pruning those lower stems and leaves so that they never touch the soil is super important, as is using stakes and twine if a plant is leaning over. You want to give pests as few access points to the plants as possible. Remove any wilting leaves or discolored leaves ASAP and toss them in the trash.

Your squash plants are likely to have pest problems if you're gardening organically—that's just a fact. But if you stay active in your garden, you can catch issues early before they become major problems. If you do find yourself with a major problem, I would honestly just remove the affected plant, roots and all, and chunk it before I'd turn to using a bunch of pesticides. Plant something that's not in the cucurbit family in its place.

Troubleshooting Squash Growing Issues

Honestly, if there's a plant in the garden that can have 99 problems, squash is the one. Unless you're a huge fan of squash, you may find that growing this plant just isn't worth it. Let's look at some of the 99 things that can go wrong growing squash and how you can treat and prevent them.

Yellowy-Brown Spots on Squash Leaves

This could be caused by a fungal disease called leaf blight. It thrives in warm, humid conditions and can cause leaves to die and fall off. Remove any damaged leaves and spray the remaining leaves with a baking soda solution.

If you've seen squash bugs in your garden, the yellow spots could also be signs of damage where they've sucked sap from the leaves.

Squash Fruits Turning Brown/Falling Off/Shriveling Up

If some of your fruits are still developing normally, then this is likely a pollination issue. A bee never visited the female flower in question with pollen picked up from a male flower. A simple solution is for you to step in and ensure every little baby squash gets pollinated. (Learn how to hand pollinate squash.)

If all of your squash fruits are rotting or if hand pollinating still doesn't fix the issue, then you might have a soil deficiency that's causing blossom-end rot. This typically happens when there's not enough calcium in your soil. Amend with an organic calcium fertilizer like gypsum.

Squash Plant Only Producing Male Flowers

Male flowers have skinny stems, while female flowers boast a tiny swelling that will become the mature fruit if the flower gets pollinated in time. Squash plants typically produce male flowers first, with female flowers following after a couple of weeks. Sometimes, too much rain or an unexpected cold spell can delay female flowers. If, after a couple of weeks, you still only see male flowers, you might have a nutrient deficiency. Consider doing a soil test to see if you need more calcium or phosphorous.

Squash Leaves Turning White

If it looks like someone spilled baby powder on your plants, you've probably got a fungal disease called powdery mildew. This is a super common problem, especially in warm, humid conditions. Powdery mildew can reduce a plant's productivity and overall health by hindering photosynthesis.

I typically treat powdery mildew by pruning the most-affected leaves, cleaning the are around the plants of any fallen plant debris, and then spraying the remaining leaves of the plant with a baking soda spray. Baking soda, AKA sodium bicarbonate, is a natural anti-fungal. (Learn more about treating powdery mildew.)

Make sure that any affected plant parts get thrown in the trash instead of the compost pile. Clean your pruners with rubbing alcohol afterwards to avoid spreading the disease.

If you've had issues with powdery mildew before, I recommend looking for disease-resistant varieties the next time you're shopping for seeds.

How to Harvest Summer Squash

Your squash fruits should be ready for harvest about 45 to 60 days after planting, depending on the variety you're growing. Pick your squash when the fruits are still relatively small. That's when they'll be more tender, contain fewer seeds, and taste their best. Squash fruits can practically double their size overnight, so when in doubt, go ahead and pick. Plus, harvesting the mature fruits regularly tells the plant to focus its energy on producing more fruit.

To harvest squash, use a clean pair of pruners or a knife. Cut the stem about an inch above the fruit. Like with pumpkins, leaving a little bit of stem prevents the fruits from molding or drying out.

You can typically expect to get about 5 to 10 squash per plant, depending on how diligently you pruned. You can also harvest squash blossoms, which are considered a culinary treat. Pick male flowers so that you don't sacrifice a future fruit.

Store any fruits you're not enjoying immediately in the crisper drawer of your fridge inside a plastic bag for a couple weeks. You can also slice and blanch squash before storing it in the freezer.

Time to Grow Some Squash

That's all there is to growing your own organic squash in your vegetable garden. May your harvests be large and the squash pests be few.

Thanks for being here and helping to make gardening ordinary!