Companion planting uses the natural relationships between plants to foster a healthier, more productive garden environment. Broccoli, a member of the brassica family, is a heavy feeder requiring consistently rich soil and is highly susceptible to pests like the cabbage worm and flea beetle. Selecting the right planting partners improves the broccoli’s access to nutrients, provides natural pest defense, and maximizes garden space. This technique creates a balanced micro-ecosystem where different species actively support the needs of the large, nutrient-hungry broccoli plant, leading to a more successful harvest.
Protective Companions: Deterring Pests and Disease
Many common broccoli pests are deterred by plants with strong, aromatic scents, which camouflage the brassica from its attackers. Herbs like dill, mint, and thyme release volatile compounds that confuse insects searching for a host plant, reducing the likelihood of pests laying eggs. Dill is particularly effective against cabbage worms, and its flowers attract beneficial insects like parasitic wasps and ladybugs. The strong odor of alliums, such as garlic and chives, repels a wide range of pests, including aphids, snails, and flea beetles. Garlic also possesses mild antimicrobial properties that can help prevent the spread of certain fungal diseases in the soil.
Marigolds are a well-known repellent, specifically deterring nematodes in the soil and aphids above ground, while their bright blooms attract beneficial insects. Nasturtiums serve a different but equally valuable function as a trap crop, luring aphids and cabbage worms away from the broccoli. These pests prefer the peppery leaves of the flower, and once the nasturtiums become heavily infested, they can be removed and disposed of, protecting the primary crop.
Growth-Enhancing Companions: Improving Soil and Yield
Broccoli benefits significantly from companions that improve soil quality and retention due to its high demand for nutrients and water. Low-growing leafy greens, such as lettuce and spinach, make excellent companions because they occupy the ground level without competing with broccoli’s root structure or height. This low canopy acts as a “living mulch,” shading the soil to keep the roots moist and cool, which helps prevent premature bolting.
Root vegetables like beets and radishes are beneficial because their root systems grow at different depths than broccoli’s shallow, fibrous roots. Beets access different soil layers, minimizing nutrient competition and helping to aerate the soil. Their presence helps break up compaction, allowing for better water infiltration and deeper root development for the brassica.
Legumes like bush beans fix nitrogen in the soil, but they must be used carefully with broccoli. Too much nitrogen can lead to excessive foliage growth at the expense of a tight head. When planted at a slight distance, they contribute to overall soil fertility by hosting nitrogen-fixing bacteria in their root nodules. Chamomile is also a unique companion, drawing beneficial insects and possibly contributing micronutrients to the soil.
Plants to Strictly Avoid in the Broccoli Patch
Certain plants should be strictly avoided in proximity to broccoli because they compete too intensely for resources or increase the risk of pest and disease problems. Other members of the brassica family, including cabbage, kale, and cauliflower, are poor companions. They are heavy feeders, leading to direct competition for limited nutrients like nitrogen and calcium. Planting them together also creates a concentrated target for shared pests, greatly increasing the risk of a widespread infestation.
The nightshade family, which includes tomatoes, peppers, and eggplants, should be kept away from the broccoli patch. These crops are also heavy feeders that rapidly deplete the soil of nitrogen and calcium, directly competing with broccoli. Furthermore, tomatoes and broccoli have conflicting soil pH preferences; tomatoes prefer a slightly acidic environment while broccoli thrives in a more neutral to slightly alkaline pH.
Aggressive growers and high-demand crops like corn, squash, and sunflowers are also best planted elsewhere. Sunflowers can easily shade out the lower-growing broccoli, reducing the sunlight it needs, and they are heavy feeders that compete for nutrients. Strawberries are another problematic neighbor, as they are nutrient-hungry and attract pests like slugs and aphids that will readily move onto the broccoli plants.