Choosing the right companion plants for tomatoes is one of the easiest things you can do to boost the health and overall productivity of your tomato crops. By growing the right combination of plants next to one another, you can help to deter pests and increase the chances of getting a plentiful supply of crops come harvest time.
Until recently, the idea of growing certain plants together so that one benefits the other – known as companion planting – was based on folklore and tradition. That’s all changing now, though, and a lot of research is going into the use of plant partnerships that can improve ecosystems in gardens and veg patches, making it easier than ever for home gardeners to have beautiful and productive outdoor spaces.
Mixed plantings with a range of fruit, veg, flowers and herbs growing together can far better support a host of different pollinators, as well as helping to prevent depletion of nutrients in the soil, not to mention deterring and confusing pests that can no longer easily home in on their favorite snack or habitat. Disease is far less likely to spread if it can’t easily travel from one plant of the same species to another too.
So if you're learning how to grow tomatoes, you'll want to make sure you know the best companion plants for tomatoes so you can add them to your plot too and boost the potential of your crops.
Why should you use companion planting for tomatoes?
The planting of single crops in long, straight rows is asking for trouble. In other words, creating a monoculture. Your garden or your veg patch is a dynamic ecosystem and each plant you grow is influenced by chemical signals it receives from other plants surrounding it, the network of underground fungi around its roots, and the way insects interact with it. Single plantings of one crop may be easier to harvest, but that benefit is far outweighed by all the disadvantages associated with a monoculture.
There’s also an argument for planting crops that like the same weather conditions and soil together, reducing the amount of additional food and water you need to provide. Some good plant partnerships mean that one helps loosen the soil, allowing the other to get its roots down more easily, or one might provide shade that will benefit the other crop and reduce the number of weeds by cutting down the light.
Best herb companion plants for tomatoes
Herbs are super easy to grow, so why not learn how to create a herb garden and add a few of these favorites alongside your tomato crops?
Plant it among your tomatoes and its strong aroma will deter thrips (tiny pests that disfigure leaves and fruits and spread disease).
It's a good idea to plant basil in pots rather than in the same raised garden bed ideas or growbag as the tomatoes as it needs less water than they do.
Chives will help to repel aphids from your tomatoes if you plant them nearby. Remove the flowerheads before the chives go to seed, though, or you’ll find that you have them everywhere next year!
There's more tips on how to get rid of aphids in our expert guide.
3. Lemon balm
Lemon balm is a great choice for companion planting for tomatoes. Grow it nearby and allow it to flower so that it attracts a whole host of pollinators to your tomatoes, which will encourage a better crop. Keep the lemon balm well watered in dry spells but out of winter wet.
This is a great herb for attracting hoverflies, which eat many of the pests that can attack tomatoes. Plant it as part of your container gardening ideas or in beds alongside your tomatoes and keep it well watered.
One thing to remember with how to grow parsley is to cut it back regularly to stop it going to seed and dying back.
This is invaluable as one of the top companion plants for tomatoes as it deters tomato hornworms. These are green caterpillars that eat tomato foliage but are really hard to spot as they’re the exact color as the leaves.
Best flower companion plants for tomatoes
It's not just herbs that can be used as companion plants for tomatoes. Flowers also have many benefits when it comes to companion planting, so why not add some of these to your veg patch and see if it improves your tomato crop?
1. White clover
Plant white clover in between tomato rows in your kitchen garden ideas as a weed suppressant. Go for a low-growing variety like ‘Wild White’ that will tolerate being stepped on when the tomatoes are picked, and cut it down before it sets seed to keep it in check and stop it spreading too much.
Don't forget, there's more tips for how to get rid of weeds and stop them spreading in our guide.
The strong aroma of marigolds will help to repel tomato hornworm and slugs. It's easy to learn how to grow marigolds from seed, plus they are relatively maintenance free if you keep the soil around the plants just moist
These flowers are loved by aphids. They are an excellent choice when it comes to companion plants for tomatoes as they can basically be used as a ‘sacrificial plant’ to draw aphids away from your tomato plants. Let the nasturtiums scramble around the bases of your tomato plants.
Best vegetable companion plants for tomatoes
Want to stick to vegetable crops in your veg patch? The good news is there are plenty of other veg that make excellent choices as companion planting for tomatoes. Take your pick from our favorites.
Plant radishes around the base of each tomato plant as a ‘trap crop’ to draw flea beetles away, helping to minimize damage to the tomato foliage.
If you've already read our advice on growing radishes, you'll know that they mature very quickly, so sow a new batch of seeds every few weeks. This means that you will then have a regular supply of new young plants to add in as and when they’re needed throughout the tomato growing season.
2. Dwarf beans
Alternate dwarf beans with rows of tomatoes and their shorter height will help create a layered effect. This improves air circulation, which is vital in the fight against tomato blight. Make sure that you remember to water the beans well in dry spells.
Learn how to grow asparagus alongside tomatoes in the veg patch and it will help fend off harmful nematodes that attack the roots of tomato plants. In turn, the tomatoes will help to repel asparagus beetle. It's a win-win!
What not to plant with tomatoes
Just as there are beneficial choices for companion planting for tomatoes, there are also some options that can have a negative impact on your tomato crops. Try and avoid planting the following crops near your tomatoes.
- Any vegetable in the cabbage family (including broccoli, kohlrabi and cauliflower) because it will inhibit the growth of the tomato plants.
- You might be keen on learning how to grow potatoes, but make sure you keep them away from your tomatoes. They are in the same family as tomatoes, so will compete for the same nutrients as well as attracting the same pests and diseases.
- Sweet corn is another one to avoid, partly because just like tomatoes it attract tomato hornworm, and also both sweet corn and tomatoes are heavy feeders so will try out outcompete each other and deplete the soil. You can find how to grow sweet corn successfully in our grow your own guide.
Sarah is a freelance journalist and is lucky to be able to write about her two main passions: gardening and food. She recently took on an allotment too, and is really loving growing all her own fruit and veg then bringing it home to try out in new recipes for her food and gardening blog, A Cook's Plot (opens in new tab).