Cromaine District Library Shares Thinking Sustainably: Companion Planting

Press release from the Cromaine District Library:

May 2, 2021

Thinking Sustainably: Companion Planting One of the most magical things about gardening is that no matter how long you’ve been doing it, there is always more to learn about the subject. There is such a wonderful variety of methods, styles, and creative ideas in designing and managing a garden.

I love exploring some of the many gardening methods, like biointensive gardening, permaculture, square foot gardening, or the well-known and well-trusted basic organic gardening method. But no matter which gardening methods we may prefer, we all tend to face some of the same gardening setbacks, and deal with some of the same questions. For example, how can I discourage pests in my garden without resorting to toxic chemicals? How can I make better use of space in my garden? Why are some of my plants stunted or struggling, while others are growing so well? Believe it or not, companion planting can answer all of these questions and more.

Discouraging Pests in the Garden Naturally

We all want to keep bugs from munching on our crops, but it’s important to remember that using general purpose pesticides can very often do more harm than good. Organic or not, methods like insecticides, bug traps, and other generic, all-purpose pesticides are often non-discriminatory, which means that they will harm both undesired pests and beneficial insects like pollinators. And that only makes for lower biodiversity in the garden, lower quality soil (which is the foundation for your garden life!), and lower response to environmental or biological stressors. In other words, your plants are less happy and healthy without a diverse community of insects, microbes, mycorrhizal fungi, and other life forms in the soil and around your crops.I try to avoid using pesticides of any kind in my garden as much as possible. Even organic and biodegradable methods, like Diatomaceous Earth, are non-discriminatory in the insects they kill. D.E. can kill aphids, but it also kills ants, bees, worms, ladybugs, and other beneficial insects. Companion planting provides a different way to manage pests in the garden, centered around the idea of relying on the natural food chains and life cycles of your pests to keep them under control. For example, we can reduce aphid populations by attracting ladybugs and bees, which feed on these pests. Plants like calendula, chives, cilantro, cosmos, dill, marigold, yarrow, and others, do very well to attract ladybugs and bees into the garden. The ladybugs and bees will feed on the aphids and other undesirable pests, protecting your crops. Herbs are also particularly wonderful companion plants to deter pests, especially when grown with a variety of other flowers or crops. Keeping a diversity of plants in your garden space, and including herbs in your arrangement, makes your garden so visually and olfactorally diverse that pest bugs have a hard time finding the crop that they’re looking for. This can deter pests for a while, or even prevent pests from finding your crop at all. Another way to reduce pest damage in the garden is through the use of trap crops, which are also known as “sacrificial crops''. They attract pests toward themselves and away from the sensitive plants you are growing. Aphids and other pest insects will feed on the trap crops until the bees/ladybugs have a chance to arrive--for example, radishes and nasturtiums are trap crops for members of the squash family like pumpkins and zucchini, so I plant them around my squash plants to keep aphids from heading straight for my squash. Borage is a good trap crop for pests like tomato hornworms, and has tons of pretty blue flowers that bees love. Calendula and marigold are also great for this purpose. In fact, French marigold is a great trap crop for various pests, and is also said to release pesticidal chemicals from its roots. I plant marigold wherever I have room for it in my garden, but avoid planting it near beans, which is the only crop that I know of that marigold does not grow well with. The trap crop you choose to use in your garden depends on what you want to plant--so give it some careful research and give it a try! Beautiful and tasty Nasturtium flowers are a great trap crop to prevent cucumber beetles from decimating your squash crops.

Using Every Inch of Space In The Garden

It never hurts to arrange your plants in a way that saves space--and companion planting can help us do just that, while also improving the vigor and health of partnering plants! For example, sunflowers can help you grow your vining crops vertically while also providing an abundance of garden benefits. Sunflowers can serve as a trellis for climbing plants like peas, beans, and small squash, mini pumpkins, cucumbers, and more.Sunflowers attract pollinators in the summer, allowing for pollination of the sunflowers as well as your vining crop and other nearby crops. Keep in mind that this also allows for the protection of your crops from common pests, since pollinators can attack aphids and other undesired insects! Sunflowers feed birds in the fall, bringing more biodiversity to your garden, and grow so well in a variety of soils that they can even help repair damaged, dry soil. To take your sunflower growth a bit further, consider adopting the Native American Three Sisters growing method, which involves growing your squash varieties around your corn, which acts as a trellis for your nitrogen-fixing beans. Like other space-saving companion planting methods, the Three Sisters method can save space and support vigorous and healthy plan growth. I love including sunflowers in my garden because it’s a wonderful companion plant that also offers benefits to encourage a healthy garden overall. The companionship between sunflowers and its companion plants is a two way street! Plants like squash/pumpkins have large leaves that can help keep the soil cool and shade out weeds, and legumes like beans help to fix nitrogen in the soil, making the nutrient more bioavailable to nearby plants.

Preventing Stunted and Struggling Plants

After looking at some of our previous examples of companion planting, you may have realized that you’ve been companion planting your whole life without even realizing it! Even the most subtle companion planting can benefit your garden, as long as you remember which plants do not grow well together. When incompatible plants are grown too close to one another, issues can develop such as poor growth, increased insect infestation, and other gardening problems. For example, plants in the Brassicaceae family (mustards like broccoli, cauliflower, kale, cabbage, and more) should not be planted next to plants in the Solanaceae family (nightshades like tomatoes, peppers, eggplants, and more). These two plant families generally do not grow well together, and can even stunt one another’s growth when planted side by side. Instead, consider planting companions like oregano, beans, carrots, nasturtium, and others near your cabbages and broccoli. As for your tomatoes and peppers, consider companions like marigolds, parsley, cilantro, and basil. This can lead to more vigorous and tasty veggies, with decreased insect problems. Another incompatible plant pairing is members of the Allium family (onions, chives, garlic, etc.) with peas, because Alliums stunt the growth of peas. Dill and carrots are also incompatible neighbors, since they are both in the parsley family and may cross-pollinate, leading to small or underdeveloped carrot roots. Strawberries are bad companions for brassica family members because they are known to attract slugs, which can quickly decimate your cabbage and broccoli plants. And there are many more incompatible plant pairs! It can be overwhelming to try and make every plant pairing perfect, but I like to at least reference a companion planting chart as I draw up my garden plans in the spring. The chart below is from One Creative Mommy.

This press release was produced by the Cromaine District Library. The views expressed are the author's own.