Companion Plants For Tomatoes & Peppers | Polytunnel Gardening (2024)

Tomatoes and peppers are amongst the most popular polytunnel crops. While they are generally relatively easy to grow, there are a range of problems that can occur. Growing them with the right companion plants for tomatoes and peppers can help.

Technically fruits rather than vegetables, these are crops that are often far easier to grow undercover than outdoors in a UK garden. If you have a polytunnel you are already ahead of the curve. But companion planting can also help to improve the quality and size of your yield.

Here are some examples of companion plant combinations that you could try:

Fruit and Veg That Make Good Companion Plants for Tomatoes and Peppers

First of all, a note on growing tomatoes and peppers together: this suggestion comes with a caveat. Some gardeners and gardening books will tell you never to plant members of the Nightshade or Solacaceae family together. Plants in this family include potatoes, tomatoes, peppers and aubergines. The reasoning is that planting these crops together can be a problem due to the potential for disease to spread between them.

But bigger problems arise with diseases etc. when members of this family are grown in the same bed after each other. Growing them together, therefore, can sometimes be a better option, especially when space is limited. By planting tomatoes and peppers together, you can move them together in a crop rotation system. This may make things easier in a smaller space.

It is also worth bearing in mind that these crops grow at the same time, and like similar conditions. Peppers can also benefit from the shade and humidity created by tomato plants nearby.

Whether you grow your tomatoes and peppers together or not, here are some other fruits and vegetables that can make good companions for both of these common polytunnel crops:

Asparagus – You do not only have to grow annual crops in your polytunnel. You can also consider a range of perennial options. Asparagus is one of the best known perennial vegetables. One down side of growing it is that the beds can take a while to become established. Rather than leaving the bed empty between asparagus harvests, you could consider growing tomatoes, peppers and other companion plants. This will help you make the most of time and space in your polytunnel.

Climbing Beans – Tomatoes are not particularly nitrogen-hungry plants. They need a good boost of potassium to flower and fruit well. But nitrogen fixing climbing beans can work well between and amongst cordoned tomato plants.

Cucumbers – Like tomatoes and beans, cucumbers could also be grown up cordons or supports to make the most of a smaller growing area. They can do well alongside your tomatoes and peppers because they require similar growing conditions.

Carrots – Plant carrots alongside your tomatoes and the carrots may be somewhat smaller as a result. But many people believe that the plant combination will increase the overall yield from a growing area. Consider planting some carrots early and harvesting them before tomatoes really take off. You could also perhaps then consider a second carrot crop once tomato plants are past their best.

Squash – Perhaps along with beans, in addition to your tomatoes (and perhaps peppers), you could also consider adding squash to such polycultures. As in the famous ‘three sisters’ planting scheme with squash, beans and sweetcorn, the squash can serve the function of shading the soil and creating good ground cover.

Alliums – Onions, garlic, chives and other alliums can all work well as companion plants for tomatoes and peppers, as they can for a wide range of other crops. Their strong smell can work to repel or distract a wide range of pests that might otherwise plague your plants.

Lettuce (Or other low-growing leafy greens) – Finally, you might also consider slotting some low-growing and fast growing leafy greens into the spaces between and beneath tomato and/or pepper plants. These can fill gaps in planting and make the most of the space available early in the season. Later, they can benefit from a little shade and help create ground cover to retain moisture and reduce weeds.

Herbs That Make Good Companion Plants For Tomatoes and Peppers

Whether you are growing tomatoes and peppers in the ground, in raised growing areas or in containers, herbs are excellent companions. Perennial herbs can be sown around the edges of annual beds, or in pots close by. Annual herbs can work well planted alongside tomatoes and peppers in your annual beds. Here are some herbs that make excellent companion plants for these crops:

Basil – Basil and tomatoes and peppers don’t just work well together on the plate. They work well together in your polytunnel garden too. Basil is said to repel a range of insect pests. It may also improve the growth of nearby tomato plants – and some gardeners even swear that it improves the flavour of your fruits. It can also spread to give good ground cover.

Mint – This is another common, fragrant herb that can create good ground cover. Mint is also said to repel certain pest species that plague tomatoes and peppers. It is also anecdotally said to improve the health of tomato plants grown nearby.

Parsley – Parsley is another great choice for planting around and beneath tomato and pepper plants. The parsley can help these plants by creating ground cover and drawing in beneficial insects. But the parsley will also be aided by the shade provided by the tomatoes and peppers in the height of summer.

Sage – Like so many other aromatic herbs, sage can also work well when planted close to your tomatoes and peppers – drawing in beneficial insects, and confusing a range of pest species.

Bee Balm – This is another aromatic herb that is said to improve the health and flavour of tomatoes and peppers. Bee balm also, as the name suggests, helps to draw bees and other pollinators into your polytunnel garden.

Coriander – Coriander is another excellent culinary herb that works well when planted close to tomatoes and peppers. It is said to repel or distract a range of pest species, and can also attract beneficial predatory insects.

Oregano – Oregano is another herb commonly used to create ground cover and attract beneficial insects and repel others. It makes an excellent companion plant for tomatoes and peppers, as it does for a range of other plants.

Rosemary, Thyme, Marjoram – Dry climate Mediterranean herbs like rosemary, thyme and marjoram may also be excellent additions around the edges of a polyculture with tomatoes and/or peppers in it. These plants are all particularly good at attracting a range of beneficial insects to your polytunnel.

Anise – Anise is another herb that can certainly draw in the beneficial wildlife. But it is also said to improve the essential oil yield of other aromatic herbs grown nearby. So it may increase the efficacy of other companion plants when added to your polycultures.

Flowers That Make Good Companion Plants For Tomatoes and Peppers

A number of flowers will also help to increase productivity and yield when planting in polycultures in your polytunnel. Here are some that may be particularly efficacious when grown near your tomatoes and/or peppers:

Borage – Borage deters common tomato pests but also helps by drawing nutrients from deep below ground as a dynamic accumulator. When chopped and dropped, it can feed the soil and feed nearby tomato and/or pepper plants. What is more, borage blooms over a long season and is great for attracting bees and other beneficial insects to your polytunnel.

Marigolds – Research has suggested that planting marigolds in between tomato plants is beneficial because the marigolds like similar conditions. But it may also help because they excrete a chemical from their roots which kills harmful root-knot nematodes in the soil.

Nasturtiums – Nasturtiums which are planted a short distance from tomato and pepper plants can act as a trap crop. They can lure aphids to feast on them rather than on your prize tomatoes and peppers. The flowers also draw in beneficial aphid predators. Of course, nasturtiums can also provide an additional yield of edible flowers and leaves.

Calendula – Another potential edible flower, calendula could be another good flower to grow amongst tomatoes and peppers. This is another flowering plant that can draw in a range of pollinators over a relatively long blooming season.

Dandelions – Finally, while generally viewed as a ‘weed’, it is worthwhile noting that dandelions can actually be beneficial in your garden in a range of different ways. Their deep tap roots are also great at bringing nutrients up to the soil surface when chopped and dropped before they go to seed. And the cheery yellow flowers attract beneficial insects too. What is more, they also release ethylene gas, so could allow your fruits to ripen more quickly.

There are, of course, plenty of other beneficial plants that you could consider including in polycultures which contain tomatoes and/or peppers. Just avoid certain plants – for example, tomatoes and peppers are not goodcompanion plants for brassicas.

What do you grow with your tomatoes and peppers? Let us know in the comments below.