Companion planting is a gardening technique where different plant species are grown in close proximity to provide mutual benefits, enhancing growth, protecting against pests, and improving soil health. Raised beds are a popular choice for cultivating strawberries because they offer superior drainage, which prevents root rot and allows the soil to warm up faster. The elevated structure also reduces the risk of soil-borne diseases. Understanding which plants to pair with your strawberries and which to keep away is important for maximizing the yield and health of your crop within the limited space of a raised bed.
Companions That Improve Strawberry Health
Strategic companion planting ensures strawberries receive both protection and nutritional support. Certain aromatic herbs and flowers function as natural pest deterrents, masking the sweet scent of the berries. Planting alliums like chives, onions, or garlic near your strawberries uses their pungent odor to repel common pests such as slugs and aphids. The strong scent of sage performs a similar function, making it more difficult for insects to locate the plants.
Other companions work by attracting beneficial insects that prey on strawberry pests. Borage attracts pollinators and parasitic wasps that help control garden nuisances. Marigolds, especially French marigolds, release a substance that suppresses root-knot nematodes in the soil. These microscopic roundworms severely damage strawberry roots, making this a valuable defense mechanism.
Legumes such as bush beans or peas are excellent choices because they fix atmospheric nitrogen through a symbiotic relationship with soil bacteria. This nitrogen is released into the soil, acting as a natural fertilizer for the strawberry plants. Low-growing crops like spinach also offer benefits, as their roots grow at a different depth than strawberries, minimizing competition for water and nutrients.
Plants to Avoid in Strawberry Beds
It is important to understand which plants are detrimental to strawberries, particularly those that act as hosts for shared diseases. The nightshade family, which includes common garden vegetables like tomatoes, peppers, potatoes, and eggplant, should never be planted near strawberries. These plants are susceptible to the soil-borne fungal disease Verticillium wilt. The fungus can remain active in the soil for years, and planting strawberries after a nightshade crop significantly increases the risk of infection.
When Verticillium dahliae infects a strawberry plant, it clogs the vascular system, causing the outer leaves to brown and wilt. This leads to stunted growth and often plant death, which is a major concern for small, contained environments like a raised bed. Also avoid aggressive plants, as strawberries are low-growing and can be easily overshadowed. Large, leafy vegetables or tall crops will compete for sunlight and consume a disproportionate amount of water and nutrients, reducing the berry harvest.
Maximizing Space and Layout in Raised Beds
The confined nature of a raised bed requires careful planning to accommodate companion plants without overcrowding the strawberries. Allocate about one square foot of space for each strawberry plant to allow for adequate air circulation and growth. Use the perimeter of the bed for low-profile companions that do not cast shade, such as chives or thyme, which can be tucked in close to the edges.
For plants that require more vertical space, like climbing beans or peas, a trellis should be positioned just outside the strawberry footprint to train the vines upwards. This utilizes the vertical dimension without shading the sun-loving strawberries. Placing a taller companion, such as borage, at the north end of the bed will ensure it does not block the sunlight for the shorter strawberry plants throughout the day. This strategic placement ensures all plants receive the necessary light while maximizing the limited growing area.