Updated: Sep 22, 2020
Companion Planting – the practice of growing two or more different plants together for the beneficial effects they have on each other – is a subject that has become fashionable as the organic food and home-grown movement has become popular, but has been an agricultural tradition for at least 8,000 years.
When the Mesoamericans transitioned from a nomadic hunter-gatherer society, to a more settled agrarian one, they found the wild progenitors of beans, maize and squash all growing together. These Neolithic farmers took the wild plants and cultivated them together to provide a nutritious, varied and healthy diet. The concept of companion planting continued in North America up until the time when Europeans arrived and started exploring the New World. The Iroquois named the system Three Sisters or Deohako. Each First Nation had its own legend about these plants, the common thread being that the sisters were very close and stronger together than they were apart, which helped the people survive.
The concept of companion planting is as relevant today as it was thousands of years ago. Using the Three Sisters as an example, the three plants each offer something to their companions: the maize grows strong, tall stalks that allows the beans to climb and spread. As the beans reach out, they tie the maize stalks together, increasing their stability. The beans, as they grow, also take nitrogen out of the air, and when they die back and decompose, this nitrogen is released back into the soil for the squash and maize to take up in their growth. Maize and squash are both notoriously nitrogen-greedy plants. The squash spreads its vines at the base of the maize and beans, outcompeting weeds for space, which could grow up and choke the beans. The squash also provides ground cover, retaining moisture, and keeping its ‘sisters’ roots cool. The density and prickliness of the squash also act as a physical deterrent to pests and predators.
All three together create a polyculture, whereby each plant uses different nutrients for growth, and then returns these nutrients to the soil as they die back. Each sister has a different root structure, helping break up and aerate the soil at different depths, which is important in irrigation, and as they all grow to different height, they make the most efficient use of sunlight as they can. Moreover, for the farmer, it allowed them to protect their communities from devastation, as it was unlikely any one single pest or disease would wipe out all three crops, ensuring that they always had something to harvest to see them through the winter.
In our own gardens, we can take this ancient knowledge and apply it to our own plants, cultivating different species together to encourage growth and fertility, deter pests, attract pollinators and act as a ‘sacrifice’ to help your more valuable crops out. Companion planting also can help enhance the taste of your fruits and vegetables – I know it’s not objective, or scientifically-proven, but in my opinion my strawberries taste a lot better and offer greater yield having been grown with borage, garlic and marigolds.
Planting crops that attract natural predators to the pests of their neighbours is a biological control that helps avoid chemical pesticides, which can harm not just the critters you are trying to kill, but the entire garden food chain and are blamed for decimating the bee population globally. For example, growing French marigolds with strawberries helps your strawberries in two ways. First, the flowers are a magnet to hoverflies, which in turn feed on aphids like greenflies. Second, the marigold, being quite pungent to various insects, deters root knot nematodes – little worms – that can wipe out a strawberry patch.
Whereas borage, which are attractive plants in their own right, are like a nectar superstore for bees, which while they are in the neighbourhood will also pollinate your strawberries, thereby increasing your yields. Borage also enhances the sweetness of your strawberries and in themselves are a great source of Vitamin C and have various culinary and herbal applications. Using poached egg flowers at the base of raspberries or blackcurrants will also attract pollinators, and growing yarrow in your vegetable beds will attract ladybirds and hoverflies which will eat your pests.
Nasturtiums are jolly little border plants, but when planted next to cabbages or fruits susceptible to aphid attacks, make for a great sacrifice plant, as the pests will prefer to attack and infest your nasturtiums, rather than your cabbages, kale and cauliflower (cabbage white caterpillars) or tomatoes, cucumbers and sweetcorn, as they’ll attract the blackfly and greenfly and take one for the team.
Similarly, planting garlic and carrots together can save your carrots from carrot root fly, as the pungent smell of the garlic will not only keep away any marauding vampires, but also drive off carrot root fly.
Companion planting is the way that God intended us to grow plants, as in nature different plant varieties grow together symbiotically, and strangely enough – or not – actually go together well on your dinner plate. I have included a small table below suggesting the different crops you can grow together. If you want to learn more about companion planting, or any other aspect of permaculture, leave me a message below. At RenewEL we’d be delighted to help you plan your garden or allotment.
Table: Suggested companion planting groups and benefits
+ Basil: Improves flavour, repels pests + Beans: Adds Nitrogen
+ Borage: Improves flavour, attracts pollinators, repels pests
+ Garlic: Repels pests, discourages blight
+ Sage: Deters pests
+ Nasturtiums: Attracts beneficial insects
+ Thyme: Improves growth and flavour
+ Petunias: Attracts beneficial insects
+ Rosemary: Deters pests
+ Marigolds: Deters pests
+ Beetroot: Improves flavour
+ Yarrow: Deters pests
+ Strawberries: Suppresses weeds, retains moisture
+ Onions: Repels pests
+ Beans: Adds Nitrogen
+ Broccoli: Repels pests
+ Sweetcorn: Provides cover
+ Beans: Adds Nitrogen
+ Marjoram: Improves taste
+ Lavender: Attracts pollinators
Image credit: Anna Juchnowicz.