Ultimate Guide to Companion Planting
Ultimate Guide to Companion Planting
Companion planting is a tried and tested technique for growing certain fruit and vegetables together to help boost growth, maximise space and protect your crops from pests. But, knowing what combination of fruit and vegetables to grow together can be difficult. Planting the right foods side by side has huge advantages — and choosing the wrong combination can be disastrous.
Farmers and horticulturists have used companion planting for centuries, yet its complicated nature has meant that many gardeners are hesitant to try it. We’ve joined with Suttons Seeds, gardening experts and suppliers of flower and vegetable seeds, to find out what foods you can plant together and which you should always keep apart to get your garden growing at its full potential.
How does companion planting work?
The reason companion planting works so well is because a mixture of root systems is created beneath the soil, which improves the structure of the earth. Some roots spread widely, while other roots grow deeply and help to bring nutrients to the surface. Unlike monoculture — which is the agricultural practice of growing one type of plant, crop or livestock at a time — polycultures that work together are not as threatened by pests and disease.
However, the drawback of companion planting is knowing what to plant together and what to keep apart. Some fruits and veg seem to get along fine, but others really seem to dislike each other.
How to use companion planting when growing your own fruit and veg
Broccoli is typically one of the easiest vegetables to grow and one of the most nutritious. A member of the cabbage family alongside sprouts and cauliflower; broccoli will usually mature in six to eight weeks in the early summer, and can be cleared away quickly so that other vegetables can grow in the late summer/early autumn.
• Plant with dill, mint, sage, and rosemary to help stop insects that might eat the vegetable as it’s growing.
• Broccoli is renowned for being a calcium hog, which is why beetroot is such a good companion.
• Plants such as spinach, radishes and Swiss chard are all companions of broccoli.
• Celery and onions help to improve the flavour of broccoli.• Interplant with foods that don’t require a lot of room.
• Tomatoes, aubergines, potatoes, and peppers. We recommend that you don’t plant any of the nightshade family alongside broccoli. The nightshade family are heavy feeders when they’re growing, which means broccoli can’t retain the nutrients it needs to grow properly. For example, tomatoes require a lot of vitamin C and this will use up all of this nutrient in the soil, which essentially starves the broccoli.
Loose, sandy soil is best for growing carrots. Try pulling your crop out of the soil before they reach their maximum size, if you want to make sure you get them at their best.
• Peas, beans and tomatoes.
• Carrots love to be surrounded by plants in the nightshade family. Tomatoes can also shade the heat-sensitive carrot, as it secretes a natural insect deterrent (solanine) which deters the carrot rust fly.
• Ensure that your tomatoes are planted 15 inches from your carrots; any closer and they will stunt the growth of your carrots.
• Carrots also help tomatoes grow by breaking up the soil and allowing more air and water to enter the roots of the tomato plant.
• Carrots are vulnerable to the same soil-borne diseases, so planting them away from each other minimises the risk of the disease spreading.
• Coriander and dill. These excrete harmful chemicals that damage the growing carrots.
• Parsnips and carrots are part of the same family, but don’t often prosper when growing next to each another. Both are susceptible to attacks from the carrot fly, and more of the same species in one area will attract even more of these flies.
You can plant cucumbers almost anywhere in your garden, as long as the soil is warm and rich in nutrients in sunlight. However, a stressed cucumber results in a bitter crop – so it’s important to tend to their requirements, so that you can yield a tasty vegetable throughout the summer.
• Nasturtiums can stave off cucumber beetles, which are responsible for causing bacterial wilt. They can also attract predatory insects (such as spiders and ground beetles) that eat the cucumber beetle, which helps the cucumber to stay alive and grow.
• The cucumber requires room to grow — approximately six feet of horizontal space per plant. This is another reason that the nasturtium flowering plant is the perfect planting mate, as it doesn’t take up too much of the growing area.
• Potato. This is because the potato will compete for water within the soil, compromising the cucumber’s ability to absorb enough fluid.
• Sage and basil. Cucumbers do not grow well when planted next to aromatic herbs, as both adversely affect the flavour of the plant. Cucumbers are made up of 95% water, so the aroma is easily absorbed.
This plant grows in trenches in the ground. Once a potato has grown, you can start growing others by planting a piece of that potato, or a whole one, back into the ground. Although potatoes generally cause problems for other crops that are growing in the same space, they have their own requirements and their own companions to help them grow properly.
• Horseradish. As well as predatory insects that help to fend off pests, the horseradish can help to increase the potato’s disease resistance, which allows the potato to get stronger and resist disease.
• Sweet alyssum. This helps to attract predatory insects (like wasps) that help ward off pests such as white grubs, wireworms, the potato beetle, and the potato leafhopper – all of which are responsible for damaging crops.
• The potato is unable to grow next to many fruits and vegetables, because most other plants that are grown for food attract pests.
• Cucumbers, tomatoes and raspberries attract insects that threaten the potato. Many of the nightshade family, of which the potato is a part, also threaten the plant because they are susceptible to the same diseases. Planting them next to each other creates excellent conditions for certain fungal bacteria to thrive.
Other friends and enemies
There are lots of combinations depending on what fruit and vegetable seeds you have to grow. Here’s a rundown of which crops to plant as companions:
Carrot, tomato, basil, coriander, dill, and parsley.
Broccoli, sprouts, cabbage, cauliflower, lettuce.
Beetroot, celery, onion potato, mint, sage.
Celery, peas, spinach, tomato, rosemary, sunflower.
Cabbage, cucumber, leek, spinach, tomato.
Cucumber, peas, pumpkin, squash, sunflower.
Broccoli, carrots, corn, onions, peas.
Cabbage, carrots, lettuce, parsnips, tomato.
Sprouts, cabbage, carrots, cauliflower, corn, lettuce.
Beans, corn, squash, marigold, nasturtium.
Beetroot, cabbage, carrots, cucumber, kale, lettuce.
Asparagus, carrots, celery, lettuce, spinach, onion.