What are Best Companion Plant Strategies for Greenhouses?

Choosing Companion Plants for Greenhouse Crops

When selecting companion plants for your greenhouse, consider the specific needs of your primary crop. For example, if you’re growing tomatoes, plant basil alongside them to repel pests and improve flavor. Basil also attracts beneficial insects that prey on tomato pests like whiteflies and aphids. Planting marigolds near tomatoes can further deter nematodes, microscopic worms that harm tomato roots. A ratio of 3:1 or 4:1 companion plants to primary crop plants is often effective.

Maximizing Space in the Greenhouse

To maximize space in your greenhouse, use a technique called “intercropping,” where companion plants are planted between rows of primary crops. Intercropping can increase yields by up to 20% and reduce competition for resources like water and nutrients. For example, planting beans or peas up a trellis near tomato plants can increase yields by providing a vertical support system for the beans while also attracting beneficial insects that prey on tomato pests. Consider a “three sisters” approach, where corn, beans, and squash are planted together to create a diverse and resilient ecosystem.

Managing Greenhouse Temperature with Companion Plants

Companion plants can also help regulate greenhouse temperature. For example, planting a row of sunflowers on the north side of the greenhouse can provide shade and reduce temperature fluctuations. Similarly, planting a row of chives or mint near the south side of the greenhouse can help cool the air by releasing moisture and reducing temperature extremes. Consider using a “green wall” system, where plants are trained to grow up a trellis or wall, to maximize space and reduce temperature fluctuations in your greenhouse.