Cilantro is an annual herb whose leaves are used in cuisine worldwide. Companion planting involves placing different plant species in close proximity to encourage mutual benefits. This strategy helps manage pests, improve soil quality, and optimize growth conditions for cilantro. Choosing appropriate neighbors for this cool-season herb can extend its harvest and enhance garden productivity.
Plants That Enhance Cilantro Growth
A variety of plants can be paired with cilantro to create a mutually supportive growing environment by managing insect populations and enriching the soil. Cilantro naturally repels certain problematic insects with its strong scent. Planting cilantro near members of the cabbage family, such as kale or broccoli, can help protect them from pests like aphids and spider mites.
Certain flowers are effective at pest control. Marigolds deter soil nematodes and help repel aphids. Nasturtiums serve as an excellent “trap crop,” drawing aphids away from the cilantro leaves.
Herbs like dill and chervil are valuable companions because they attract beneficial insects, including lacewings and parasitic wasps, which prey on common garden pests. Legumes, such as peas and beans, fix atmospheric nitrogen into the soil. This nitrogen provides a gentle nutrient boost that supports cilantro’s leafy growth.
Plants to Avoid Planting Near Cilantro
Some plants hinder cilantro’s growth due to competition, conflicting environmental needs, or the release of inhibitory chemicals. Fennel is a poor companion because it exhibits allelopathic properties, releasing compounds that stunt the growth of nearby plants. It is best to grow fennel in a separate container or location away from the main garden.
Other plants to keep separate have vastly different cultural requirements, specifically Mediterranean herbs like rosemary, thyme, and lavender. Cilantro thrives in moist, nitrogen-rich soil and cooler temperatures. These Mediterranean plants prefer dry, sandy, and well-draining soil. Placing them together forces one plant to endure unsuitable conditions, leading to poor health or premature bolting for the cilantro.
Using Taller Plants for Environmental Control
Cilantro is a cool-season plant that tends to prematurely “bolt,” or go to seed, when exposed to high heat and intense sunlight, which causes the leaves to become bitter. A strategy to delay this is using taller companion plants to provide partial shade during the hottest part of the day. This creates a cooler microclimate around the herb, extending the harvestable window.
Taller, sun-loving vegetables like tomatoes, peppers, or corn are ideal for this purpose, as their canopy shields the cilantro from intense afternoon sun. Planting cilantro on the east side of these crops ensures it receives gentle morning sun while being protected from harsh midday and afternoon heat. Tall flowers, such as cosmos or sunflowers, can also serve this shading function effectively.
Understanding the Principles of Companion Planting
The success of companion planting relies on several ecological mechanisms that improve the overall garden ecosystem. One principle is “pest confusion,” where aromatic companion plants mask the scent of the target crop, making it difficult for specialized pests to locate their host. Cilantro’s strong scent is often used to confuse pests that target other vegetables.
Another mechanism involves attracting beneficial insects, often called “natural enemies.” Plants with small flowers, like dill, produce nectar and pollen that feed predatory insects such as lacewings, ladybugs, and parasitic wasps. These beneficial insects naturally control populations of harmful pests.
The concept of “nutrient cycling” is fundamental, particularly through the use of legumes. These plants host specialized bacteria that convert atmospheric nitrogen into a form usable by plants, acting as a slow-release fertilizer for nearby crops. Additionally, plants with deep taproots, like carrots, can break up compacted soil, improving aeration and water penetration for shallow-rooted neighbors like cilantro.