10 Companion Plants You Should Always Grow Next to Winter Squash, According to Gardening Experts

Beans

Winter squash may not set a lot of fruit, and the leaves can look pale if there isn't enough nitrogen in the soil. One way to boost your soil's nitrogen content is by growing beans (Phaseolus vulgaris). "You can interplant beans with squash to fix nitrogen in the soil," says Annie Klodd of the Minnesota Landscape Arboretum. "It works best to plant pole beans because they will grow very tall and won't be out-shaded by the squash plant leaves." Bush beans also work but may get crowded out by the large size of the squash leaves, and it may be difficult to find the beans for harvest. "Pole beans grow high if trellised, so it's easier to pick them in an interplanted situation," says Klodd. 

• Zones: 3 to 10
• Size: For pole beans, 6 feet tall or more x 2 feet wide per plant
• Care requirements: Full sun; well-drained soil with neutral acidity

Dill

Tall and willowy, dill (Anethum graveolens) brings beauty to the garden and flavor to the kitchen. But it's also useful as a companion plant to deter pests from winter squash. "I personally love to use herbs," says garden author Teri Speight. "Dill is one of my favorite tried, tested, and true herbs to use as a pest deterrent throughout my vegetable garden—particularly around my squash." She adds that another benefit of dill is that you can use it to pickle an overabundance of vegetables.

• Zones: Perennial in zones 8 to 10; annual in zones 3 to 7
• Mature size: 2 to 5 feet tall x 1 foot wide
• Care requirements: Full sun; well-drained soil

Radishes

Gardeners love radishes (Raphanus sativus) because they are low-maintenance and grow fast enough to have multiple harvests in a season. Another reason to grow radishes is because they help deter insects attracted to your winter squash. "The radish is said to be most effective against the cucumber beetle, a pest in more humid areas," says author Jacqueline Soule. Cucumber beetles attack all kinds of similar plants, including your winter squash.

• Zones: 2 to 11
• Size: 6 to 8 inches tall x 1 to 2 feet wide
• Care requirements: Full sun; loamy, sandy, moist, well-drained soil

Zucchini

Varieties of summer squash (Cucurbita pepo)—like zucchini or yellow squash—attract the same types of pests as winter squash. You can use this to your advantage by growing summer squash as a sacrificial trap crop. "One of the worst pests of squash is squash vine borer, because it can kill an entire plant quickly," says Klodd. "You can try to distract squash vine borer from your most desired winter squash plants by planting a 'sacrificial' squash plant nearby. For instance, a zucchini or yellow squash plant that you don't mind if it gets killed by insect pests."

She notes that you should only do this if you currently have a vine borer problem in your garden. "There is also no guarantee that it will work, but it does decrease the chance that the insect will infest the plants you care about most," says Klodd.

• Zones: 3 to 11
• Mature size: 12 to 24 inches tall x 24 to 36 inches wide
• Care requirements: Full sun; fertile, well-drained soil

Corn

Corn (Zea mays) has long been a companion plant for squash and is part of the Native American "three sisters" planting technique—the principle that corn, beans, and squash are a united family. "They each bring something important and useful to the venture," says Soule. The tall corn plants provide some much-needed shade to winter squash plants.

• Zones: 3 to 11 
• Mature size: 6 to 8 feet tall x 2 feet wide
• Care requirements: Full sun; well-drained soil
  

Nasturtiums

There are a lot of reasons to love nasturtiums (Tropaeolum spp.). These attractive vine-like flowers put on quite the display of blossoms, and the foliage adds visual interest, too. Plus, their peppery bite is a boon to salads and other dishes. Another added benefit is that nasturtiums help steer aphids away from winter squash, as the aphids may find the nasturtiums more appealing.

• Zones: 2 to 11
• Size: 6 to 24 inches tall x 12 to 24 inches wide
• Care requirements: Full sun to part shade; well-drained soil
  

Sunflowers

Sunflowers (Helianthus annuus) and winter squash are great companion plants. "The squash provide a soil cover to keep the ground moist, enabling the sunflowers to take root. The sunflowers return the favor when the squash plants need a buffer from the intense summer heat," says Speight. Another bonus for planting sunflowers near winter squash: "It appears to bewilder the squash vine borer, a major pest in some areas," says Soule.

• Zones: 2 to 11
• Size: 2 to 16 feet tall x 12 to 36 inches wide
• Care requirements: Full sun; well-drained soil

Borage

The blue flowers of borage (Borago officinalis) are a good way to attract pollinators to the garden—bumblebees seem to love them. Borage is one of Soule's favorite companion plants for winter squash, as it can help repel squash bugs that want to chew on your crop. Plus, borage has some soil-improvement properties, such as adding calcium back into the soil. Be aware that this plant can be somewhat toxic to people and pets.

• Zones: 3 to 11
• Size: about 2 to 3 feet tall x 1 foot wide
• Care requirements: Full sun; well-drained soil

Peas

Like beans, peas (Pisum sativum) are another legume that can help fix nitrogen in the soil. As the peas grow and climb their trellis, they also provide a bit of partial shade for the winter squash. You may want to consider planting a late-season crop of peas so that they mature at the same time as your winter squash.

• Zones: 2 to 11
• Size: 24 to 36 inches tall 
• Care requirements: Full sun; fertile, well-drained soil

Rosemary

Insect pollination is important for squash plants—if there aren't enough bees and butterflies working the flowers, pollination will be low, and your winter squash crop yield will suffer. There are plenty of flower options to attract bees to the garden, but the herb rosemary (Salvia rosmarinus) is a great choice. Bees love rosemary—it's easy to grow, prevents pests, and tastes delicious. 

• Zones: 7 to 8, or grown as an annual 
• Mature size: 36 inches tall x 36 to 48 inches wide
• Care requirements: Full sun; moist soil