Companion plants for tomatoes: which plants are best to grow with tomatoes?

Regina

I studied horticultural sciences at university and in my free time you can find me in my own patch of land, growing anything with roots. I am particularly passionate about self-sufficiency and seasonal food.

Favourite fruit: quince, cornelian cherry and blueberries
Favourite vegetables: peas, tomatoes and garlic

Which plants are most compatible with tomatoes? We will show you which plants make the best neighbours for these delicious fruits and will give you expert tips for companion planting with tomatoes.

Tomato plants growing next to lettuce — Tomatoes can be grown in companion with many other vegetables, most notably salads [Photo: Hirundo/ Shutterstock.com]

Companion planting is probably the most primitive form of growing vegetables of different species together in one area. Whether in a garden bed, a greenhouse or in a pot, various plants can work together to have a positive influence on one another. Using this type of cultivation for tomatoes (Lycopersicum esculentum) offers both advantages for the plants themselves and diversity on the plate.

Contents

Advantages of companion planting with tomatoes
What should I plant next to tomatoes?
- Good companion plants for tomatoes
- Bad companion plants for tomatoes

Advantages of companion planting with tomatoes

The advantages of planting companion plants for tomatoes over a monoculture, with only one vegetable species, become apparent throughout the season:

Companion planting is generally more fruitful and significantly more diverse than monocultures.
The different types of vegetation provide shade for the soil and protect it from drying out.
Nutrient-hungry plants (or heavy feeders) alongside undemanding ones (light feeders) prevent the soil from wearing out.
Friendly neighbour plants can protect each other against pests and diseases.

For these reasons, you should place the tall-growing tomato plants next to some low-growing vegetables that require only a small amount of nutrients. This way, the soil is always shaded by leaves and never dries out completely, even during the height of summer.

Tomato plants and marigolds — A mixed culture of tomatoes and marigolds aids in keeping nematodes away from the plants soil

Some plants even produce substances that can ward off pests, for example, the pungent garden cress (Lepidium sativum) which keeps (woolly) aphids away from tomatoes. The diversity of plants also prevents pests and diseases from plaguing your garden uncontrollably. Within this cluster of plants, there will always be one that pests tend to avoid. Therefore, companion planting for tomatoes with some good neighbours can be a gentle way of deterring uninvited visitors. The height difference between plants can protect the soil, from both wind erosion and heavy rain; whilst reducing evaporation during a hot summer. The different root systems loosen the soil at different depths and provide food for earthworms and other soil organisms after the harvest. This way, they serve as a source of nutrients for the plants that will grow in the bed in the following season. But how should you fertilise companion plants? It is impossible to supply each crop with nutrients individually. Our tip: use fertilisers with a long-lasting effect such as our Plantura Tomato Food. This is particularly suitable for companion planting as it ensures nutrients are gradually released by the soil organisms so that even light feeders can absorb them at their own pace without any issues.

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What should I plant next to tomatoes?

In companion planting, different plants with different needs are grown in one bed at the same time. And just as in real life, while some plant combinations thrive side by side, other plants are terrible neighbours to each other. Below we will show you the best companion plants for tomatoes and the plants you should not grow next to tomatoes. For more detailed information on these perfect plant combinations, we recommend you read our special article.

Good companion plants for tomatoes

Low-growing vegetables with low nutrient requirements are well suited for planting at the base of tall-growing tomato plants. Therefore, lettuce (Lactuca sativa), spinach (Spinacia oleracea), basil (Ocimum basilicum), chamomile (Matricaria chamomilla) and parsley (Petroselinum crispum) make great neighbours for tomatoes. They can even be planted or sown long before the tomatoes, in March or April. Their roots will loosen the soil and thus ensure for better soil conditions for the tomato plants. As the tomatoes grow, they shade the soil, reduce evaporation and save a lot of water, especially in summer.

Due to their essential oils, parsley and basil also keep those annoying aphids away!

Carrots (Daucus carota) and parsnips (Pastinaca sativa) make full use of the space underneath the large nightshades, loosening the soil with their roots and providing good drainage.

Garden cress (Lepidium sativum), common beans (Phaseolus vulgaris), celery (Apium graveolens) and most cabbages (Brassica sp.) are generally considered suitable companion plants for tomatoes. Onions (Allium cepa), leeks (Allium ampeloprasum) and garlic (Allium sativum), too, are plants that grow well with tomatoes. They keep away whiteflies (Bemisia sp.) from the surface and can even drive away voles from your garden bed.

Pot marigolds (Calendula officinalis) and tomatoes are decent companion plants as well. Marigolds grow close to the ground and keep away annoying nematodes. Because of their flowers, pollinators become drawn to the marigolds, which help achieve an abundant tomato harvest.

Tomatoes in mixed culture — Salads are good neighbours for tomatoes [Photo: Otto Born/ Shutterstock.com]

Bad companion plants for tomatoes

Other plants, however, are not suitable companion plants for tomatoes. This is the case if, for example, the plants have completely different habitat requirements or compete for nutrients with the tomatoes. Bad neighbour plants exude natural root excretions that cause both plants to grow insufficiently, sometimes even causing stunted growth. Even though different nightshades are more or less compatible with each other, you should avoid growing tomatoes together with potatoes (Solanum tuberosum). Potatoes are almost always infested with late blight (also known as potato blight), which they can easily transmit to the neighbouring tomatoes.

Other heavy feeders with high nutrient demands are also bad companion plants for tomatoes. In the long run, they will exhaust the soil and the plants will experience deficiency symptoms.

Planting peas (Pisum sativum) directly with tomatoes is also not advised, as both would suffer from each other’s root excretions and similar habitat requirements. Fennel (Foeniculum vulgare) and red cabbage (Brassica oleracea var. capitata f. rubra) are also not recommended to grow as neighbours for tomatoes.

Cucumbers (Cucumis sativus) are often planted together with tomatoes, but the plants do not get along. Companion planting tomatoes and cucumbers will do both plants more harm than good. Cucumbers have completely different habitat requirements and are often infested with mildew, which they then transmit onto the tomato plants. In extreme cases, both plants grow poorly and bear hardly any fruit.

Tomatoes and cucumbers growing together — Unfortunately, tomatoes and cucumbers are not good neighbours [Photo: Valery Rybakow/ Shutterstock.com]

By choosing good companion plants for your tomatoes, you can achieve quite a lot of positive effects, both for the plants themselves and for the soil. But it is not only the tomato’s neighbours who play an important role, but also the subsequent crops in the garden bed. We have compiled everything you need to know about crop rotation for tomatoes in this article.