People need people – there are those we get along with and everybody is happy and thriving, but there are also those who are simply not beneficial to our personal growth, and best to avoid.
And so it is with plants…
What is companion planting?
Companion planting is about either the beneficial or harmful effects of one plant on another. Nature ‘invented’ plant interactions and through careful studying over centuries as to how plants affect one another we have been able to apply these facts in agriculture and in the home garden as a means to organically control diseases and pests and to promote healthy plants and crops.
How does companion planting work?
There are various forms of companion planting and they can either act singularly or combined:
- Some plants grow flowers which attract and sustain beneficial insects and pollinators that are vital for fruit formation and production, e.g. the flowers of dill or fennel, if planted near squashes will attract the pollinators necessary for a good yield.
- Some plants benefit others by enriching the soil with scarce or much needed minerals, e.g. nitrogen-fixing legumes like beans, peas and clover. Weeds, ironically, are excellent at ‘digging’ their roots deep into the soil in search of minerals that other plants may not be able to reach. If these plants are dug into the soil before they set seed, these minerals and nutrients can be made available to garden plants and veg.
- Certain plants have insect or fungal repelling properties that benefit plants planted around them. Strong smelling plants like marigolds and garlic will either confuse or simply repel pests, like whitefly or wooly aphids, while Calendula will repel nematodes in the soil.
- Other plants are specifically planted as decoys or sacrificial plants, because certain pests prefer them and they are used to lure pests away from crops. A good example is Nasturtium, which not only adds cheer to any garden with its bright blooms, but will also efficiently trap aphids and whitefly. These plants can then either be sprayed or lifted and burnt to get rid of the pests.
- Some plants directly benefit others in a physical way by offering support or shelter from sun and wind. A classic example is the ‘Three Sisters’ combination of beans, squash and corn, favoured by the Native Americans. The corn offer support for the beans to climb up on, the beans enrich the soil with their nitrogen-fixing properties and the squash acts as a groundcover, suppressing weeds and keeping the soil moist and cool.
- Certain plants are allelopathic, i.e. they release biochemical called allelochemicals, which either have beneficial or harmful effects on other plants. In nature this herbicidal effect acts as a natural survival mechanism to eliminate competition. This can be used to great benefit in the vegetable garden by either grouping plants together or avoiding using them in combination.
Companion planting in the herb and vegetable garden:
Best Friends Forever
These plants benefit one another either through their allelochemical interaction and insect-repelling properties or by providing support and shelter:
Beans potatoes, corn, parsley, pumpkins
Beetroot the onion family and all your leafy vegetables (spinach, lettuce)
Brinjals beans, lettuce and peppers
The cabbage family onions, celery, sage, leeks, potatoes, tansy, thyme, penny-royal
Carrots parsley, peas, lettuce and the onion family
Cucumber radish, lettuce, beans, peas, artichokes
Corn lettuce, pumpkins, runner beans, peas, peppers
Peppers and chilies cucurbits, lettuce, bush beans
Peas cucumber, radish, turnips, corn, carrots, beans
Potatoes cucumber, sunflowers, beans, peas
Pumpkins corn, runner beans
Tomatoes garlic, parsley, rue, celery, asparagus, carrots and the onion family
Strawberries borage, lettuce, radish, parsley
Neighbours from Hell
These plants should not be planted near or next to those listed as they can be affected adversely, simply won’t thrive and growth and seed production can be stunted:
The legume family (beans, peas) don’t like fennel and members of the onion family
The cabbage family (Brassicas) don’t like rue, tomatoes, strawberries, carrots
Coriander doesn’t like fennel
Garlic doesn’t like peas, beans, cabbage, strawberries
Potatoes don’t like tomatoes, brinjals, apples, pumpkins
Pumpkins don’t like other members of the pumpkin family and potatoes
Basil doesn’t like rue
Sage doesn’t like rue, cucumbers, Swiss chard
Strawberries don’t like gladioli, mint, rosemary, thyme
Tomatoes don’t like rosemary, dill, potatoes and the cabbage family
Companion planting is an exciting journey into the secret world of plants. It’s a dash of magic, a bit of necessary silent warfare and a solid reminder that no single living thing stands alone and we’re all part of keeping that fine balance!