Written by Ingrid Hoff
Some things are just better together, like peanut butter and jelly, camping and s’mores, and sunflowers and squash. That last one might need a bit more explaining. In the garden, just like in life, there are a number of relationships going on, between the plants, the insects, and even the weather. As with most relationships there are some that are more positive than others. And if we are talking about plants, because that’s what we do, some plants just get along better together. This positive plant relationship is the idea behind companion planting.
Companion planting is polyculture, or the growing of many different plants together. It’s the opposite of monoculture which is what traditional modern agriculture is patterned around (lots of the same plants growing together). To me companion planting is just using good sense and it’s been used both historically and in modern day by many cultures around the world. It’s not a new idea, just a good one.
Probably the most famous version of companion planting is something called the three sisters. This was a technique historically used by a number of North American Indigenous groups to grow corn, beans and squash. The three crops were planted together to benefit each other. The corn would grow tall and provide support for the beans to climb. The beans would increase the soil fertility by fixing nitrogen from the atmosphere. And as the squash vines spread out over the ground, they provide shade to the soil acting like a mulch preventing weeds and retaining moisture.
While some gardeners I know treat the idea a bit akin to consulting horoscopes (perhaps a bit more folklore than facts) there is actually some good science behind it and a lot of benefits to be had. Some of which include an increase in crop productivity, some plants just seem to grow better together, but this is not always something that is easy to measure or quantify. Other benefits that are easier to see and measure are pest control, improved pollination, and the creation of habitat for beneficial insects. So, let's take a closer look at companion planting. Here are a few of the reasons you should take a closer look at playing botanical matchmaker this year in your veggie garden.
Hedging your bets, or a backup plan if one crop fails. By planting different plants, you increase the odds that you will have success. If you only planted tomatoes and you lost them all to blight then your season would be bust.
Maximizing space, you can often grow more plants in the same area of land if you take advantage of their different growth patterns. Just like growing beans up a corn stalk, or growing short lettuce plants underneath tall broccoli.
Protection, by growing tougher plants with ones that might be more tender you are taking advantage of their strength. So, the brunt of climate (sun, frost, wind) will fall on the sturdier plant. A great example is growing lettuce (which is easily burnt in the heat of the sun) in the shade of broccoli.
Trap crop, the best offence is a good defense, or as I like to call them… sacrificial plants. This is when you purposely plant something you know will be desirable to a pest. Then the pest will flock to the trap plant and you are better able to see and treat them. A great example is to plant nasturtiums to attract aphids and caterpillars and keep them away from eating your cabbage.
Confuse the enemy, if they can’t find it then they can’t eat it. There are two main methods here, to confuse visually and based on smell. Bare soil might look “neater” but it actually makes it easier for some insects to find their food, they can see the contrast of the green against the brown earth. So, the more green you have in the garden the harder it is for pests to find their host plants. By using fragrant plants, marigolds and garlic are great examples, the smell of the leaves can confuse pests looking for a tasty treat.
Positive hosting, this is the idea that by planting plants that have lots of nectar and pollen it will bring in both beneficial insects and pollinators. Some great examples include planting dill to attract ladybugs, or perhaps calendula to attract hover flies. And my example at the beginning of sunflowers and squash comes from the fact that squash flowers can sometimes be hard for pollinators to find, sunflowers are like a beacon calling them in.
I really could go listing numerous plants that benefit each other but it really is a long list. It’s best to do a bit of research about the specific crops you plan to grow and find out if they would be better together or apart. Do an internet search or talk to one of the GARDENWORKS experts in store. You might find some information on things that should not be planted together, because, well… relationships are complicated. But please keep in mind it’s not like these plants are toxic to each other (there are a few plants like the black walnut tree which are legitimately toxic but there are none we need to worry about in the veggie garden). It’s just that sometimes if you have a choice of what to grow where, it might be good to space some of them out (a bit like trying to separate combative siblings, you parents out there know what I mean).
If I had to choose my favourite combination it would have to be basil and tomatoes. Not only are they good together on pizza and pasta but growing them together is said to improve the flavour of the tomatoes and the strong aroma of the basil will help to repel insect pests. So, yes, it’s true that some things are just better together, like basil and tomatoes.