Companion planting involves strategically placing different crops to achieve mutual benefits. Many home cooks hope to pair common culinary herbs like basil and cilantro for convenience. While they might seem like a good match due to their frequent use together in the kitchen, their contrasting needs create significant challenges for growing them side-by-side. This guide examines the fundamental differences between the two herbs and offers practical alternatives for successful companion planting in your garden.
Fundamental Differences in Growing Needs
Basil and cilantro are not well-suited for planting together because their preferences for temperature and moisture are nearly opposite. Basil is a true lover of heat, performing best in warm conditions with air temperatures between 70°F and 90°F. This herb is highly sensitive to cool weather and will suffer or cease growth entirely if temperatures drop too low. Furthermore, basil requires consistently moist soil to support its robust, leafy growth, often needing water two to three times per week, especially during the summer.
Cilantro is a cool-weather annual that quickly struggles when the mercury rises. It thrives in moderate temperatures, ideally between 50°F and 85°F, and is notorious for “bolting,” or prematurely going to seed, when daytime temperatures exceed 75°F. Its water needs are also different; while cilantro needs consistent moisture to germinate, it is more drought-tolerant once established and can suffer from root rot or fungal issues if the soil is kept as wet as basil prefers. Attempting to satisfy basil’s need for heat and frequent watering will almost certainly cause the cilantro to bolt and fail.
Ideal Companion Plants for Basil
Since basil is a warm-weather plant requiring abundant sun and consistently moist, rich soil, it pairs naturally with other vegetables and herbs that share these requirements. Tomatoes are the classic companion, as their shared need for full sun, warmth, and deep, regular watering makes them highly compatible. The strong aromatic oils in the basil leaves help deter common tomato pests, such as the tomato hornworm, offering a natural layer of protection.
Peppers, both sweet and hot varieties, also make excellent neighbors for basil, as they thrive under the same hot conditions. Other beneficial companions include:
- Oregano acts as a low-growing ground cover, helping to shade the soil and retain moisture.
- Chamomile is believed to increase the production of essential oils in basil, potentially enhancing its flavor and aroma.
- Flowering marigolds attract beneficial insects and deter root-knot nematodes in the soil.
Ideal Companion Plants for Cilantro
Cilantro’s preference for cooler temperatures and its tendency to bolt quickly make it a better companion for cool-season crops and plants that can offer protective shade. Pairing cilantro with leafy greens like lettuce, spinach, and kale is effective because they all thrive during the milder weather of spring and fall. Cilantro’s pungent scent also provides a natural pest defense for these tender greens by repelling aphids and spider mites.
Root crops like carrots and radishes are good companions because their deep root systems do not compete with cilantro’s shallow roots. Tall, summer-loving plants, such as tomatoes, can be strategically placed to cast partial shade on the cilantro during the hottest part of the day, which helps to slow the bolting process. Furthermore, cilantro’s characteristic umbrella-shaped flowers, when allowed to bloom, attract beneficial predatory insects like lacewings and hoverflies, which help control pest populations throughout the garden.