For tens of thousands of years, agriculture has been practiced as more art than science, but there was science to it. Early farmers used observation, trial and error and experimentation to bring the best production to their fields. One of the most powerful tools in our agricultural ancestors’ tool box was observation of the natural world. Observing the conditions, groupings and seasons that best suited wild varieties of plants offer broad insight into their domesticated cousins needs. In permaculture these are referred to as guilds, plants that offer mutual benefits to each other when planted together. In gardening and farming, the practice is called Companion Planting.
Some plants like full sun and grow a broad leaf which offers shade to another plant underneath it. Some plants are nitrogen fixers and work well planted in beds near plants that love extra nitrogen. A whole host of plants attract pollinators and should accompany plants that cannot self-pollinate. Where one plant struggles or has special needs, another plant offers something to fill that need…that’s the core of companion planting.
The Benefits of Companion Planting
It’s pretty common knowledge among gardeners than beans restore nitrogen to the soil (referred to as nitrogen fixing). Beans are the big one, restoring plenty of the one of the most important macronutrients plants need. That’s why beans are part of the famous “Three Sisters” playing an important role in the dynamic relationship between corn, beans and squash. But there are nitrogen fixers you can use in the garden like clover, winter peas or other legumes.
Many plants play a vital role in managing pests in the garden. Some plants (like onions, garlic and mint) fend off aphids. While other plants (like anise) will attract predators that will feed on aphids and other pests. Root vegetables are susceptible to other types of pests and Flax is known to produce oils that repel those types of invaders.
This one is big, right? I mean, we need to get those blooms pollinated or we aren’t going to eat! Plants like tomatoes, peppers and squash need a little help getting pollinated and that can be done by hand or it can (and should) be done by our natural helpers like bees and butterflies. Basil, nasturtium, lavender, rosemary, and many others offer a good reason for pollinators to visit your garden. And while they’re there, they can get some work done.
Want to see sweeter peppers or tomatoes? Who doesn’t? Try planting basil between your plants. (In fact, basil is one of those super companions that improves tomato health and vigor, improves fruit flavor, repels a handful of pests AND attracts pollinators when in bloom. It’s also very attractive!) Chives, onions and nasturtiums are also known to improve flavor in various plants. This one is tricky because where one companion may improve the flavor of some plants, it can turn other plants bad…so be careful who your neighbors are.
There are a whole host of plants that can be used to condition challenging soils. Plants with aggressive, deep rooting natures can loosen soil and leave valuable organic matter behind when they’re cut down. Others may have large, aggressive root growth that can improve porosity and soil aeration.
Refer to our quick reference list of Companion Plants for specific information on plants that do well together (or should be kept separate).
There is also a great little article about companion planting from the Penn State Extension office worth a quick read. And we would recommend checking out this longer, more in depth look at companion planting from Organic Authority.