Companion planting is an agricultural strategy where different plant species are grown in close proximity to encourage mutual benefits. This practice is particularly helpful for heavy feeders like cabbage, which demand significant nutrients and are highly susceptible to common pests. Cabbage, a member of the Brassicaceae family, is a target for numerous insects and quickly depletes nitrogen from the soil. Selecting neighboring plants helps gardeners naturally protect their crop, improve soil health, and enhance productivity.
Plants That Repel Cabbage Pests
The primary threat to cabbage is the imported cabbageworm, the larval stage of the Cabbage White butterfly. Aromatic herbs are excellent companions because their strong odors confuse the adult moths, masking the scent of the cabbage plant. Thyme contains thymol, a natural deterrent that disrupts the diamondback moth’s egg-laying behavior.
Other powerful scent-maskers include celery, dill, and oregano. Interplanting these fragrant herbs directly among the cabbage rows makes it harder for pests to find their host plants. Strong-scented French marigolds also repel pests, including whiteflies and nematodes.
Nasturtiums function as a classic trap crop. The cabbage white butterfly prefers to lay its eggs on nasturtium leaves, distracting them from the cabbage and protecting the main crop. Flowers like yarrow and borage attract predatory insects, such as parasitic wasps, which prey on cabbage worms.
Companions That Boost Cabbage Growth
Cabbage plants require a continuous supply of nitrogen to form dense, leafy heads. Legumes such as bush beans and peas are beneficial companions because they host Rhizobium bacteria in their root nodules. These bacteria fix atmospheric nitrogen into a form available to the cabbage, helping sustain the crop.
Certain low-growing plants improve the microclimate around the cabbage roots, which prefer cool and moist soil. Lettuce and spinach, planted beneath the larger cabbage leaves, act as a living mulch. This shades the ground, reduces water evaporation, and keeps the soil temperature stable.
Root vegetables like carrots and radishes provide a non-competitive benefit by occupying a different layer of the soil profile. Carrots grow downward, using space the cabbage roots do not, and their root systems help to loosen the soil. This improved structure allows for better aeration and water infiltration.
Plants That Harm Cabbage
Interplanting cabbage with other members of the Brassicaceae family should be avoided, including broccoli, cauliflower, kale, and collards. They share the same susceptibility to pests like the cabbage worm and flea beetle. Planting them together creates a concentrated food source, leading to a rapid buildup of pests and the spread of diseases like black rot.
Heavy feeders that compete directly for nitrogen are also poor companions. Planting cabbage near corn, tomatoes, or squash, which also have high nutrient demands, results in stunted growth. Shade-producing plants, like pole beans or large gourds, can also harm cabbage by blocking the sunlight needed for full head development.
Layout and Timing for Success
The physical arrangement of companion plants is often as important as the species selection. Intercropping involves planting repellent herbs like thyme or dill directly between the cabbage plants within the row. This strategy maximizes the scent-masking effect, making it difficult for pests to navigate.
Deterrent plants can also be used in a border planting technique, where a continuous line of nasturtiums or marigolds is established around the perimeter of the patch. This creates a protective barrier that intercepts incoming pests.
For nitrogen-fixing companions, such as peas, they should be planted slightly before or at the same time as the cabbage to ensure the bacteria are active when the cabbage needs the nutrients. Using fast-maturing crops like radishes allows for succession planting, utilizing space efficiently before the cabbage canopy fully develops.