Companion planting is the practice of growing different crops in close proximity to maximize the health and productivity of the garden ecosystem. This strategy is based on the idea that certain plants can mutually benefit one another through pest deterrence, nutrient cycling, or providing beneficial shade. Bell peppers are heavy feeders and belong to the nightshade (Solanaceae) family. Selecting the right companions is crucial because their shared family ties with crops like tomatoes make them susceptible to similar pests and diseases. Thoughtful plant pairings can help reduce reliance on chemical interventions, leading to a more robust and higher-yielding pepper harvest.
Essential Beneficial Companions
Aromatic herbs like basil serve as excellent companions for bell peppers due to their strong scent that helps repel harmful insects. Basil releases volatile chemicals that confuse pests such as thrips, which cause significant damage to pepper leaves and fruit. This herb also attracts beneficial pollinators, which is necessary for the pepper plant to set fruit.
Marigolds, specifically the French and African varieties, are renowned for their ability to control parasitic nematodes in the soil. These flowers release a nematicidal compound called alpha-terthienyl from their active, living roots, which suppresses root-knot and lesion nematodes. For this control to be effective, the marigolds must be planted densely and remain in the soil for at least two months before the peppers.
Tomatoes can be planted near bell peppers because both are heat-loving nightshades that share similar needs for soil pH, water, and sun exposure. Taller tomato plants can offer afternoon shade to bell peppers, which can prevent sunscald on the fruit during the hottest parts of the summer.
Carrots and onions have shallow root systems that do not compete with the deeper roots of the pepper plant for nutrients and water. Onions and their relatives emit strong odors that deter common pepper pests like thrips, aphids, and whiteflies. Other herbs also contribute to pest management by attracting predatory beneficial insects:
- Oregano attracts predatory wasps and acts as a dense ground cover to suppress weeds.
- Dill attracts lacewings and ladybugs, which prey on aphids.
Plants to Keep Away from Bell Peppers
Certain plants are detrimental to bell peppers and should be kept at a significant distance due to negative allelopathic effects or intense resource competition. Fennel is an allelopathic plant that releases chemical compounds like anethole from its roots. These compounds can inhibit the growth and reduce the yield of nearby pepper plants.
Members of the Brassica family, including broccoli, cabbage, and cauliflower, are heavy feeders that aggressively compete with peppers. These plants demand large amounts of nitrogen and other soil nutrients, which can lead to stunted pepper growth and reduced fruit production. Another incompatible pairing is corn, which acts as a host for the corn earworm. The corn earworm moth lays its eggs on the corn silks, and the resulting larvae can attack and damage pepper fruits.
While sunflowers can attract beneficial insects, their large size and allelopathic properties pose a risk to peppers. Sunflowers can cast excessive shade, and their roots may release compounds that inhibit the growth of surrounding plants. This necessitates careful placement many feet away from the pepper patch.
Strategic Layout and Spacing Techniques
The success of companion planting depends heavily on the spatial arrangement of plants within the garden bed. Proper planting density is crucial to ensure bell peppers receive sufficient light and air circulation, which helps prevent fungal diseases. A good strategy is to interplant smaller, ground-level companions like basil or onions directly between the pepper plants, maintaining the recommended spacing of 18 to 24 inches.
Using vertical space is an effective technique, especially when planting taller companions like tomatoes near peppers. Taller plants should be staked or trellised and positioned on the north side of the pepper bed to prevent excessive shade. This placement allows the peppers to benefit from indirect shade during the hottest afternoon hours without sacrificing the six to eight hours of direct sun required for fruit production.
Border Planting
Border planting involves placing pest-deterring plants around the perimeter of the pepper patch to act as a defensive barrier. Marigolds and aromatic herbs can be planted densely along the edges to create a strong olfactory and chemical shield against incoming pests.
Succession Planting
Succession planting can be utilized by planting fast-growing, shallow-rooted companions early in the season, such as lettuce. These companions can be harvested before the peppers mature and require all the available resources.