Companion planting is the art of purposely planting certain species next to each other in an effort to enhance their growth. Different plants help one another by offering protection from pests, amplifying the delicious flavor of a vegetable or fruit, keeping weeds at bay, preserving moisture, and adding nutrients to the soil. Tall, sturdy plants can even provide structure for vining varieties like beans and peas. When choosing companions, select plants with different growth habits so that they do not out compete each other for sun and nutrients. For small gardens, strategic companion planting is a must for conserving on space for a bountiful yield.
Both zucchini and summer squash (members of the Cucurbia pepo species) require lots of space in the garden, making it essential to find companions with opposite traits. They are heavy feeders and require regular, even watering. But their broad leaves and vining nature also serve a purpose—they keep weeds out and moisture in by providing ample shade for the soil. Keeping their traits in mind, you can successfully plant companions that will thrive alongside these veggies.
Three Sisters Garden
Beans, corn, and squash (like zucchini) make ultimate companions. Always planted together in Native American gardens, these sisters are inseparable. In fact, legend describes these three plants as "gifts from the gods," noting they should always be planted, eaten, and cherished together.
Each sister adds her own unique offering to the garden ecosystem. The beans (or any legume, including peas) pull nitrogen from the air and fixate it into the soil. Nitrogen-fixing plants benefit all other plants—especially heavy feeders like zucchini and squash—by providing the nutrients they need to grow. Corn, with its tall, sturdy stalk gives vining plants, like beans, a backbone on which to trellis themselves. Additionally, both corn and squash have the same moisture and soil fertility requirements, making them impeccable neighbors. The ample growth of squash and zucchini plants shade the soil and prevent the infiltration of weeds, while their spiny leaves deter rodents who might enjoy a bean or sweet corn snack.
Other Companions for Zucchini and Summer Squash
Vegetables are not the only good companions for zucchini and summer squash. Mixing edible flowers and herbs into your vegetable garden makes it pleasing to the eye. Nasturtiums and marigolds act as a "trap crop" (a crop planted to attract pests from another crop) for flea beetles and aphids. If you commonly deal with bugs in your garden, edge the perimeter of your squash plants with these two flowers. Both plants bear bright and colorful flowers that can be eaten, too. Nasturtium's spiciness adds a nip to a butter lettuce salad, whereas marigold's sweetness mellows out that of arugula.
Smelly herbs, like peppermint, dill, oregano, lemon balm, and parsley ward off pests and insects from delectable squashes. However, take care when planting different varieties together. Two strong-smelling herbs planted side by side may alter each other's taste. And two herbs that are heavy feeders can compete with each other and the zucchini plant for vital nutrients. However, booming herbs like borage must be planted next to squash. Their flowers attract honeybees—crucial pollinators for any garden—and will increase the yield of your harvest.
Plants to Avoid
Potatoes should always be planted alone, as they negatively impact a variety of vegetables. This root vegetable is a heavy feeder (maybe even more so than its squash counterpart) and it robs many nutrients from the soil. For this reason, potato farmers often rotate their crops year after year, making sure to plant nitrogen fixers in their place before reintroducing a subsequent potato crop the following year.
Pumpkins—another unruly companion—can also wreak havoc on a zucchini or summer squash crop. As members of the same species, they can cross-pollinate in a manner that can affect the outcome of the fruit.