11 Best Companion Plants For Summer Squash (And 2 To Avoid)

When it's time to harvest summer squash, whether it's for a summer squash casserole, squash cake, or stewed squash, gather all your best squash recipes because these plants produce abundantly. Before you count on your bounty a couple of months after planting, some insects may want to feast on the summer squash leaves and stems. This can negatively impact the plant if not kept at bay. Companion planting is a method that can help reduce pests in the garden as well ad attract pollinators, such as bees, butterflies, and birds, to help increase summer squash pollination and put important nutrients back into the soil.

Why Should You Plant Summer Squash With Companion Plants

Summer squash is a category of squash that grows in the summer. One of the most well-known varieties is the zucchini yet there are other varieties, such as crookneck and pattypan. "While all zucchinis are summer squashes, not all summer squashes are zucchinis," says Shawna Coronado, author of No-Waste Organic Gardening and 101 Organic Gardening Hacks. "Think of zucchini as a specific player on the summer squash team."

Companion planting can help ensure your summer squash plants have fewer unwanted insects hanging around,. "Companion planting for summer squash can be a gardener's secret weapon," says Coronado. "Companion planting creates a mini-ecosystem that promotes healthier, more resilient plants."

Growing plants that get along with summer squash can minimize unwanted pests while maximizing space and enriching the soil. A huge win-win for any gardener. "For example, legumes like peas and beans fix nitrogen in the soil, which is beneficial for squash plants," Coronado says. "Aromatic herbs and flowers can repel pests." 

The Best Companion Plants for Summer Squash

If you want to reduce pests and increase pollination, here are 11 of the best companion plants to plant with squash to help it grow healthily and abundantly. 

Beans

Beans and summer squash are good pals because they have similar growing needs and beans fix nitrogen in the soil, an important mineral for soil health. "Beans enjoy full sun and warm weather and improve the soil for future crops," says Heather Kibble, homegrown sales manager for Sakata Seed America, Inc and a National Garden Bureau member. She recommends growing bush beans instead of pole beans as they don't require a trellis.

• Botanical Name: Phaseolus vulgaris
• Sun Exposure: Full sun
• Soil Type: Loamy, well-drained
• Soil pH: Acidic to neutral

Leeks 

"Leeks are a great companion for summer squash because they can help repel pests like carrot flies and aphids," says Coronado. "Their strong scent can confuse and deter these pests, creating a protective barrier around the squash." The other benefit is that while summer squash spreads out over the soil, leeks grow upright and don't need much space. "Leeks have a vertical growth habit and a shallow root system, making them ideal for interplanting without competing for space or nutrients," she adds.  

Botanical Name: Allium ampeloprasum
Sun Exposure:  Full sun
Soil Type: Well-draining, moist
Soil pH: Neutral

Lettuce

Lettuce only takes up a little space in the garden, making it a good fit with summer squash. "Quick-growing lettuce can be planted around young squash plants in the spring to make the most of your space," says Kibble. "Make sure to harvest the lettuce regularly to make room for the squash as it spreads out." She recommends choosing lettuce varieties known as "cut and come again" so you harvest continuously and take up even less space than a typical head of lettuce. 

• Botanical Name: Lactuca sativa
• Sun Exposure: Full sun to partial shade
• Soil Type: Well-drained, loamy, 
• Soil pH: Acidic to neutral

Peas 

As a vining plant, peas typically climb a trellis vertically while summer squash takes up space horizontally, making them good companions. Peas also fix nitrogen into the soil, says Coronado, a mineral that is key for soil health. 

• Botanical Name: Pisum sativum
• Sun Exposure: Full
• Soil Type: Well-drained, rich
• Soil pH: Acidic, neutral (6.0-7.5)

Radishes

A root vegetable that grows underground, radishes grow well among summer squash. "They grow quickly and can help break up the soil, making it easier for the squash roots to expand," says Coronado. Another benefit is radishes can entice unwanted pests to themselves, helping summer squash grow. 'Radishes can act as a trap crop, luring pests like flea beetles away from the squash," she says.  While summer squash uses a lot of horizontal garden space, radishes grow below the soil so it's a great way to capitalize on space. Coronado adds that if you harvest radishes early, it gives summer squash more time to spread out. 

• Botanical Name: Raphanus sativus
• Sun Exposure: Full
• Soil Type: Well-drained, loose
• Soil pH: Acidic, neutral 

Spinach

Another leafy green that takes up minimal space and complements summer squash is spinach. "Spinach can be planted around squash plants in the spring," says Kibble. "Spinach matures quickly and will enjoy some of the shade a squash plant may provide as it grows." She recommends planting an early maturing baby spinach variety to harvest in spring or early summer. When the weather warms up and gets hot, spinach tends to bolt or go to seed. 

• Botanical Name: Spinacia oleracea
• Sun Exposure: Full sun, partial sun
• Soil Type: Well-drained, loamy, moist
• Soil pH: Acidic, neutral, alkaline

 Tomatoes 

"Tomatoes and summer squash make excellent neighbors in the garden [because] both plants thrive in similar growing conditions—full sun and well-drained soil," says Coronado. As summer squash spreads out and takes up plenty of room, this can benefit tomatoes by preventing weeds from growing and competing with tomatoes for the same nutrients. "The sprawling nature of squash can act as a living mulch, helping to suppress weeds and retain soil moisture for tomatoes," she says.

• Botanical Name: Solanum lycopersicum
• Sun Exposure: Full sun
• Soil Type: Loamy, well-drained
• Soil pH: Neutral to acidic

Oregano

A pungent aromatic herb, oregano pairs well with summer squash in the kitchen and in the garden. Summer squash relies on pollination to produce the fruit—the squash. When oregano flowers are in bloom, this attracts important pollinators to the garden to aid in pollination.

• Botanical Name: Origanum
• Sun Exposure: Full
• Soil Type: Well-drained, sandy
• Soil pH: Neutral (6.5-7.0)

Basil

One of the star herbs of summer, basil is a wonderful culinary pairing with a lot of summer produce, including summer squash.  When basil is planted near summer squash they work together to deter pests. "Basil repels pests, such as mosquitoes and flies while attracting beneficial insects like bees," says Coronado. Need another reason to plant basil near summer squash? "The aromatic oils in basil can also enhance the flavor of squash when grown," she adds.

• Botanical Name: Ocimum basilicum
• Sun Exposure: Full sun to partial shade
• Soil Type: Fertile
• Soil pH: Acidic to alkaline

Borage

Borage is a herb with edible leaves and blue flowers that bring important insects to the garden. "Not only does it attract pollinators like bees, which are crucial for squash pollination, but it also deters pests such as tomato hornworms," explains Coronado. When the summer season winds down and borage goes through the next stage of its lifecycle, borage leaves benefit the soil. "Borage leaves can be used as mulch to enrich the soil with valuable minerals," she adds. 

• Botanical Name: Borago officinalis
• Sun Exposure: Full
• Soil Type: Well-draining, Rich
• Soil pH: Slightly Acidic to Slightly Alkaline

Marigolds

Marigolds are a favorite to plant in an edible garden for attracting pollinators and reducing pests.  "Squash plants need steady visits from pollinators to move pollen from the male to female flowers," says Kibble. "Marigolds can deter some pests, such as mosquitos, and can draw some pests away from your squash if they like the marigolds better."

• Botanical Name: Tagetes
• Sun Exposure: Full sun
• Soil Type: Moist, well-drained
• Soil pH: Slightly acidic to neutral

Companion Plants To Avoid With Summer Squash

Summer squash has many beneficial companions in the garden yet some plants fare better when keeping their distance. Sometimes they compete for the same nutrients, and space or can spread diseases when planted near each other. 

Here are a couple of companion plants to avoid with summer squash:

Potatoes

Potatoes and summer squash are not pals in the garden since they have the same needs and will compete for them. "Potatoes compete for the same nutrients and can stunt the growth of squash," says Coronado. Another issue is they can attract the same pests and diseases, which can increase the risk of an infestation. 

Pumpkins

Pumpkins, a type of winter squash, don't fare well when planted near summer squash. Although it may be counterintuitive, planting winter squash and summer squash varieties can provoke more issues, such as attracting pests rather than deterring them. "Pumpkins, being another type of squash, can lead to cross-pollination, which might affect the quality and taste of both plants' fruits," says Coronado. She adds that because pumpkins can attract similar pests and diseases that infections and infestations can increase.