The cultivation of snap peas, a hybrid of garden and snow peas, benefits significantly from companion planting. This practice involves strategically placing different plant species near one another to create a mutually beneficial environment. Optimizing these relationships enhances soil health, maximizes space efficiency, and improves overall crop vigor. Companion planting mimics natural ecosystems, fostering an interconnected garden where species support the growth and protection of their neighbors.
Plants That Support Pea Growth
One of the most effective companion planting strategies involves pairing snap peas with low-growing leafy greens, such as lettuce and spinach. These greens serve as a living mulch, covering the soil surface and helping to suppress weed growth. This ground cover also regulates soil temperature and retains moisture, benefiting the shallow root systems of the peas.
The relationship is reciprocal because peas are legumes; their roots host symbiotic bacteria called rhizobia that convert atmospheric nitrogen into a usable form in the soil. Leafy greens have high nitrogen requirements and readily utilize these compounds provided by the peas. Planting these greens six to eight inches away from the pea trellis allows them to benefit from the enriched soil without competing with the pea roots.
Root vegetables like carrots and radishes make excellent companions for snap peas because they occupy different soil strata. Peas have a shallow root zone, extending only about a foot into the ground. Carrots and radishes, with their taproots, delve deeper, which prevents resource competition.
The growth of these root crops helps break up compacted soil, improving aeration and drainage for the pea roots above. Radishes mature quickly and can be harvested before the pea vines reach full size, clearing space and improving overall soil structure. Taller crops like corn or sunflowers can also be utilized to provide a natural, sturdy trellis for the vining pea plants, maximizing vertical garden space.
Companions for Pest and Disease Control
Specific flowering plants and aromatic herbs can be incorporated into the pea patch to protect the plants from common garden pests. This biosecurity approach often relies on strong scents to confuse insects or on plants that serve as a distraction. Nasturtiums are frequently used as a trap crop, planted specifically to lure pests away from the main vegetable crop.
Aphids, a common snap pea pest, show a strong preference for nasturtiums, migrating to the flowers instead of the pea vines. This concentration of pests on the sacrificial plant allows gardeners to manage the infestation or remove the trap plant entirely. Nasturtiums also emit a peppery scent that can confuse or repel other unwanted insects.
Marigolds, especially French marigolds, offer protection by deterring specific pests both above and below the soil line. Their roots release chemical exudates that help suppress nematodes, microscopic roundworms that damage plant roots. Their vibrant flowers attract beneficial insects, such as hoverflies and parasitic wasps, which prey on harmful pests like aphids and Mexican bean beetles.
Aromatic herbs, including basil and mint, introduce strong odors that mask the scent of pea plants, making them harder for pests to locate. Basil contains aromatic oils known to deter thrips, insects that damage developing pea pods. Mint provides dense ground cover that aids in moisture retention, but requires careful containment due to its spreading nature.
Plants That Should Never Be Near Snap Peas
Some species have antagonistic relationships that can inhibit pea growth and yield. The group to avoid is the Allium family, which includes onions, garlic, chives, and leeks. These plants release sulfur compounds and other allelopathic chemicals into the soil. These chemicals interfere with the nitrogen-fixing process performed by rhizobia bacteria on the pea roots, preventing the plants from accessing necessary nitrogen. This disruption leads to stunted growth and yellowing foliage.
Gardeners should avoid planting snap peas near species that are heavy feeders. Members of the nightshade family, such as tomatoes, peppers, and eggplants, require large amounts of nutrients and compete with peas for soil resources. This competition results in poor growth for the pea crop.
Potatoes should be kept separate from peas because both are susceptible to common diseases, such as blight. Planting them in close proximity increases the likelihood of pathogens spreading. The herb fennel releases substances that inhibit the growth of many other nearby plants, making it an unsuitable companion.