Top 10 Plant Friends
Some plants grow well together and some don’t. In the vegetable garden you can get the best out of a plant and increase its yields by companion planting and avoiding the foes. Here are some of our favourite combinations:
Green beans + Corn
Beans fall into the ‘nitrogen fixers’ category, so are good for boosting the nitrogen levels in the soil and providing nutrients to surrounding plants. Ideal as companion planting for beans is corn. Beans can tolerate a bit of light shade cast by corn, and they can use the corn as climbing support structures. The roots of each plant are at different levels in the soil and so they don’t compete for water and nutrients.
Bean foes: Avoid planting beans with onions, beets, peppers and sunflowers.
Corn foes: Avoid planting corn with tomatoes.
Tomatoes + Basil
A classic companion planting combination that is good to eat as well as grow together. It is said that basil improves the flavour of tomatoes when they grow alongside each other, but the main reason they grow well together is that the strong scent of basil repels pests that afflict tomatoes. Plus, if you leave some of the basil to flower, it will attract pollinators. When the tomatoes are ripe, pick with basil leaves and layer them together with mozzarella cheese with a drizzle of good olive oil for the perfect Caprese salad.
Tomato foes: Avoid planting tomatoes with brassicas, corn and potatoes.
Swiss chard + Alyssum
Not a common combination, but so pretty in the garden, and the leaves and flowers of sweet alyssum are actually edible with a light peppery taste that goes well in salads and is great for decorating soups and stews. Caution: the seeds are poisonous. The reason that these two plants go so well together is more than the appealing look in the veggie garden, as alyssum attracts many beneficial insects that help to control pests like aphids, and their sweet smell is a magnet for pollinators. They also make a good living mulch.
Swiss chard foes: Avoid planting with potatoes.
Potatoes + Broccoli
This companion planting combo may be a bit different in that the two plants here don’t contribute much to each other, but are more just friends in the garden. Potatoes have a hard time alongside many plants but do well with broccoli as they don’t compete for nutrition. Broccoli requires a lot of calcium and nitrogen while potatoes need plenty of magnesium and phosphate. As long as you keep up with fertilisation, these two will be happy together. Add a herb like chamomile, which can be grown with both, to the mix and you will be repelling bad insects and attracting good ones.
Broccoli foes: Avoid planting with strawberries and mustard greens.
Potato foes: Avoid planting with tomatoes, peppers, carrots, cucumbers, sunflowers, onions and more.
Melons + Marigolds
Marigolds are one of the most well-known companions in the veggie garden for their fierce smell and ability to repel some pests, trap other pests and attract pollinators. Certain varieties are also known for controlling harmful nematodes in the soil around the roots of plants like melons. Plus, they add a touch of colour to the veggie garden. Melons are one of the most compatible plants in the garden and will grow with just about anything.
Melon foes: Avoid planting with potatoes.
Marigold foes: Avoid planting with beans and cabbages.
Cucumbers + Nasturtiums
Imagine a vertical line of climbing cucumbers underplanted with flowering nasturtiums. Nasturtiums reputedly repel cucumber beetles, and they can also attract pollinators and other beneficial insects. A colourful combination that is more than just a pretty face.
Cucumber foes: Avoid planting with potatoes and sage.
Cabbage + Dill
Dill is a useful neighbour for brassicas like cabbages because of its ability to draw in beneficial insects and pollinators as well as discourage unwanted pests like cabbage loopers, aphids and spider mites. Cabbages are the ones in the combo that need more help with pest and disease avoidance, and they require nitrogen-rich soil. Use comfrey as a mulch here or make a comfrey tea to supply cabbages with an extra dose of nitrogen.
Cabbage foes: Avoid planting with broccoli, cauliflower, strawberries, brinjals and tomatoes.
Dill foes: Avoid planting with carrots, peppers, potatoes and brinjals.
Lettuce + Chives
Chives can act as a barrier plant against pests like aphids heading for leafy lettuces. There are a vast number of plants that like to grow with lettuce, with some benefitting from improved texture, but chives and garlic are two of the most beneficial to lettuces thanks to their strong aromas. Chives also have a long list of friends in the garden.
Lettuce foes: Avoid planting with broccoli.
Chive foes: Avoid planting with beans.
Carrots + Radishes
These two are surprising companions, since they are both root vegetables, but they actually don’t compete for resources. Radishes are quick to mature and don’t grow as deeply as the long taproots of carrots, so they take up nutrients from different parts of the soil. Because radishes grow so quickly, they cover the soil and act as a groundcover, and their pungent quality has pest-repelling properties.
Carrot foes: Avoid planting with brassicas, potatoes, fennel, dill, coriander and parsley.
Radish foes: Avoid planting with brassicas and turnips.
Onions + Cauliflower
The strong smell of onions will chase away aphids from those veggies that are usually plagued by them, such as cauliflower. They are also good next to the other brassicas like broccoli, kale and cabbages. Cauliflower also have pest-repelling properties so these two make a good team.
Onion foes: Avoid planting with beans, peas and sage.
Cauliflower foes: Avoid planting with peas, beans, tomatoes and strawberries.
How companion planting works
Science tells us why some plants may grow well together, and it’s interesting to explore a few of these reasons for a better understanding of how it all works:
Plants with very aromatic foliage make it difficult for pests that rely on their sense of smell to find their favourite vegetable. Using companion planting throughout the garden should have a good deterrent effect. Suitable plants include lavender, rosemary, tansy, basil, scented geraniums, thyme, feverfew, catmint, mint and alyssum.
Pollinators such as butterflies, bees and moths are essential for pollination of fruiting vegetables. There are also many beneficial predators, like ladybirds, wasps and assassin bugs, that keep aphids and other pests under control. Grow pollen- and nectar-producing plants like borage, cornflowers, Californian poppies, chrysanthemums, daisies, feverfew, lavender, nasturtiums, roses, sunflowers, sweet peas and yarrow.
These are plants that attract pests away from the veggies and should be planted around the edge of the veggie garden. Once the plant is infected, pull it out, cut it down or get rid of the concentration of pests with an organic spray. Nasturtiums, garlic chives, chives, fennel, sunflowers and violets are effective in this role.
Soil and plant doctors
Some nematodes damage the roots of a wide variety of vegetables and reduce their yield, but plants like marigolds and khakibos can fix the problem. Chamomile is often called the plant doctor because it stimulates the growth of nearby plants, its aromatic foliage acts as an insect repellent and the high lime content in its leaves makes it an effective green manure or compost crop.
These are mainly members of the legume family (peas, beans, lucerne), and their roots have nodules that release nitrogen into the ground. Other, equally valuable, plants that are good at taking up nutrients are borage, comfrey, chamomile, fennel, nasturtiums, primrose and yarrow. Add the leaves to the compost heap, dig the plants into the soil as a green manure crop, or make a green tea from the leaves and use it as a liquid fertiliser over the veggies.