Tomato companion planting – the best crops to grow with tomatoes

Did you know that companion planting tomatoes with beneficial plants can help to increase your homegrown harvest and deter pests?

The idea is simple: it just involves planting two or more different plants next to each other that are known to benefit one another.

Tomatoes are popular, easy to grow vegetables from seed, but it can be so frustrating to see your carefully tended tomato plants attacked by aphids or whitefly, or destroyed by fungal disease. 

Wherever you choose to grow  your crop – whether outside in the vegetable plot, in pots on a patio, or in a greenhouse -– companion planting tomatoes can help.

See: Companion planting – your ultimate guide

You will start to sow tomato seeds from late March to April, so at the same time consider what you will be companion planting tomatoes with.

See: How to grow tomatoes – the best ways to grow your own tomato plants

What are good companion plants for tomatoes?

Most of the knowledge around companion planting for tomatoes is anecdotal rather than scientifically proven, but it is a case of applying common sense and seeing what works well. 

'I’ve experimented in my veg patch and am pretty convinced that several combinations are worth repeating,' says planting guru Sarah Raven.

There are several plants that are considered excellent companions for tomatoes, and the tomatoes can return the favors to other plants in your garden.

'Pruning, vigilant weeding and mulch can help protect and manage tomato plants until it's time to harvest, but choosing the best companion plants can do a lot of the work naturally,' says Ron Finley, gardener and community activist whose gardening project is helping to teach communities in Los Angeles how to grow their own food.

Companion planting tomatoes with particular neighboring plants and flowers can have a number of benefits. These can include improving and adding to the soil nutrients, luring pests away from the tomato plants, or enticing essential pollinators, such as bees and butterflies to the tomato plants. 

Companion plants can also act to create a better growing environment, whether that is providing beneficial shade, support for growing plants, ground cover or by breaking up the soil.

See: Kitchen garden ideas - 10 easy ways to get started

What to plant with tomatoes to keep bugs at bay

Keeping pests off tomatoes can be a challenge as many different types like to prey on the fragrant fruits. Aphids, whiteflies, and other pests like to feed off the nutrients in the tomato plants, leaving them yellow and withered.

Companion planting tomatoes with natural defenders will help to protect them from becoming the feast of pests.

Some companion plants have strong scents that distract or repel pests that could otherwise attack the tomatoes. For instance mint helps to repel white cabbage moths, ants, rodents, and aphids, while onions are known to deter pests with their pungent aroma.

There are other companion plants and flowers that attract the predatory insects and creatures that will keep the pest numbers down. Amaranth, for example, play host to beneficial beetles that will eat the bugs that like to prey on your tomatoes.

See: 5 raised bed gardening mistakes - and Gardener Scott's advice on how to avoid them

Companion planting tomatoes with vegetables

Companion planting tomatoes with a range of different vegetables can have a number of benefits.

ASPARAGUS 'illustrates the give and take of good companion planting,' says Ron Finley. 'Tomatoes repel asparagus beetles with a chemical called solanine, and asparagus help to clear the soil of root-knot nematodes attracted to tomatoes.' 

Once asparagus has been harvested in spring, the bed can be used to grow tomatoes and other companion plants to make good use of the space. 

LETTUCE can be slotted into spaces between and beneath tomato plants to create ground cover to retain moisture in the soil and reduce weeds. In return, the shade from tomato plants in summer can help stop lettuce bolting and going to seed.

GARLIC is believed to repel spider mites and other pests with its strong smell. A trick for a homemade insecticide is burying garlic cloves 1 inch in the ground around tomato plants.

SQUASH and tomatoes require the same growing conditions so work well side by side. Also the spreading form and large leaves of squash create good ground cover, reducing water loss from the soil.

• See: How to grow garlic – a step by step guide to growing from cloves

Companion planting tomatoes with herbs

Companion planting tomatoes with herbs has the added benefit that the herbs are useful in the kitchen.

BASIL and tomatoes work well as the aromatic herb repels insects, specifically flies and hornworms, and is believed to improve yield and also the flavor of tomatoes. 

It will also draw whitefly away from the tomatoes.'If you ever have basil in a greenhouse, it will be crawling with whitefly long before the tomatoes succumb,' says Sarah Raven.

CHIVES repel aphids, nematodes and mites.

PARSLEY attracts hoverflies that feed off the pests that attack the tomatoes, and also provides ground cover.

THYME attracts a range of beneficial insects and also helps to enhance the flavor of the fruit as it ripens.

Companion planting tomatoes with flowers

Companion planting tomatoes with flowers is both beneficial and adds a pretty element to your vegetable plot.

FRENCH MARIGOLDS repel tomato worm, slugs and general garden pests. They have also been shown dispel root-knot nematodes, parasites that feed off of the nutrients in a tomato’s root system. 

NASTURTIUMS ‘are often used as a sacrificial plant so aphids and and black fly attack them but stay away from your precious vegetables,' says Emma O’Neill of Garden Organic. Nasturtiums can also attract beneficial predator insects that will eat the pests.

PETUNIAS look pretty planted close to tomatoes and can also deter a wide range of insect pests.

COSMOS will lure aphids away from your tomato plants and also attract hoverflies that eat the aphids.

• See: How to grow potatoes – a step-by-step guide

What should not be planted with tomatoes?

As well as being many beneficial companion plants for tomatoes, there are also some 'enemies' that you want to avoid planting near tomatoes.

• Brassicas (including cabbage, cauliflower, broccoli and brussel sprouts) - inhibit tomato growth.
• Potatoes - along with tomatoes are also in the nightshade family so they will be competing for the same nutrients and will also be susceptible to the same diseases.
• Corn - they both attract the same pests.
• Fennel - is quite a poor companion for many vegetables and will inhibit the growth of tomatoes.
• Aubergines - are in the nightshade family, like tomatoes, and are all susceptible to blight.