29 December 2016, Written by Ann Marie Hendry
Gardening is an art that’s deeply influenced by the environment. Every garden, from its soil type to climate and surrounding plants, presents unique conditions. These factors can shift over time, so a companion planting technique that thrives in one garden may fail in another. Yet, this doesn’t diminish the value of the practice – instead, it highlights the importance of understanding how companion planting works for your specific garden.
Companion planting involves growing different plant species together to benefit at least one of them, often by deterring pests. While some companion planting combinations are based on anecdotal evidence, scientific studies have confirmed that certain strategies can be effective. In this article, we’ll delve into how companion planting can confuse pests and ultimately help protect your crops.
Understanding How Pests Target Crops
Researchers Stan Finch and Rosemary Collier, from Horticulture Research International in the UK, investigated how pests search for suitable places to lay their eggs. Their study focused on common pests of cabbage family plants, like diamondback moths, cabbage white butterflies, and cabbage root flies. The team found that when cabbages and other brassicas were planted next to clover, the pests laid fewer eggs on the edible crops. In fact, this resulted in up to a 90% reduction in eggs from some pests.
Interestingly, clover didn’t have any special repellent qualities. The same reduction in egg-laying was observed when green card models of plants were used around the cabbage. This discovery suggests that pests are simply attracted to green surfaces in search of suitable plants to lay their eggs on. If the plant they land on is not suitable, they will move on to find a more promising location.
Using Companion Planting to Prevent Pests
What does this mean for gardeners? The answer lies in diversifying your planting. A monoculture of one type of crop in a bare, weed-free plot can increase pest vulnerability. When pests are nearby, they are more likely to land on the target crop. By using companion plants – such as clover, marigolds, or even other vegetables – around your crops, you reduce the chances of pests finding your plants. This is especially beneficial in larger gardens, where row covers may be impractical.
The benefits of companion planting extend beyond pest prevention. A layer of greenery can protect your soil by reducing erosion, conserving moisture, and even attracting natural pest predators. For example, ground beetles, which prey on slugs, prefer to hide in ground cover, while hoverfly larvae will feast on aphids after their parents have visited flowers like alyssum and poached egg plant.
Balancing Companion Plants with Edibles
While companion planting can significantly improve your garden’s health, it’s important to strike a balance. Be mindful not to overwhelm young crops with nearby companion plants, as they could hinder their growth. However, you don’t need to leave large stretches of bare soil between your rows. A lush, green canopy will not only look more vibrant, but it can also help your garden thrive.
Our Garden Planner now includes a companion planting feature to help identify which plants can benefit your crops. Simply add the plant you want to grow, click on the companion planting button, and discover which plants will work best with it.
Give companion planting a try, and share your experiences with us by posting a comment below!