Swiss chard is a resilient, leafy green vegetable that remains productive longer than most cool-season crops, thriving even as temperatures rise. This hardiness makes it a popular choice for a continuous harvest of nutrient-dense greens. Companion planting is an ecological strategy involving growing different plant species close together to create a mutually beneficial environment. This technique leverages natural interactions to improve soil health, maximize yield, and manage common garden challenges without synthetic interventions.
Companion Plants That Deter Pests
Pests like aphids, leaf miners, and slugs locate Swiss chard by scent, making aromatic companion plants an effective defense. Aromatic herbs such as rosemary and mint release compounds that confuse these pests, masking the chard’s scent. Planting a border of perennial herbs like oregano and thyme can repel smaller pests such as aphids. Rosemary is also known to deter snails and slugs from reaching the chard’s leaves.
Flowers are another successful strategy, used to repel pests or attract natural predators. Marigolds are a classic companion, deterring nematodes in the soil and confusing pests like cabbage moths and whiteflies with their strong fragrance. Calendula and chamomile also emit strong scents that repel or confuse garden pests, protecting the chard. Allowing these plants to bloom provides nectar and pollen for beneficial insects, such as ladybugs and parasitic wasps, which prey on soft-bodied pests.
Alliums, including chives, onions, and garlic, play a significant role in pest management due to their sulfur compounds. These compounds produce a strong odor that deters a wide range of pests, including leaf miners and flea beetles. Garlic can also help prevent fungal issues like mildew on chard leaves because its essential oils have fungicidal properties. Positioning these pungent plants along the edges of the bed creates a barrier against common garden invaders.
Companion Plants That Enhance Soil and Growth
Certain companion plants improve soil conditions and nutrient availability, leading to healthier Swiss chard growth. Legumes like bush beans and peas are beneficial because they host Rhizobium bacteria in their root nodules. This process, known as nitrogen fixation, converts atmospheric nitrogen into a usable form. This is helpful for heavy feeders like Swiss chard, which requires high levels of nitrogen for leaf production.
Other plants improve the soil structure, benefiting the chard’s root system. Short-season root vegetables like radishes and Daikon radishes have strong taproots that penetrate and loosen the soil. This action aerates the soil and improves drainage, allowing chard roots to access oxygen and water more efficiently. Planting taller crops like tomatoes to the west of Swiss chard provides afternoon shade during the hottest parts of the season. This shade keeps the soil cooler and reduces the risk of the chard prematurely bolting, extending the harvest period.
Plants That Should Not Be Grown Near Swiss Chard
While many plants offer benefits, some combinations can be detrimental to Swiss chard’s health. Avoid growing chard near plants that are heavy nutrient competitors, as both will struggle in depleted soil. Potatoes, which are heavy feeders and spread extensively underground, compete directly for nitrogen and other essential nutrients. Gourd family members, such as cucumbers, melons, and squash, are also strong competitors for soil nutrients and water, and they attract pests that target chard.
The most notable plant to avoid is fennel, which releases biochemicals that inhibit the growth of many nearby vegetables. Chard is also in the same botanical family as beets and spinach, and growing them in close proximity is discouraged. Since these related plants share similar nutrient requirements, they compete for the same resources and are susceptible to the same pests and diseases.