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

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

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 tomatoes.

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 have a positive influence on one another. This type of cultivation of tomatoes (Solanum lycopersicum) not only ensures diversity on the plate, but also offers many advantages for the plants themselves.

Advantages of companion planting tomatoes

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

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

For this reason, 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. 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. 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. Therefore, companion planting tomatoes with some good neighbours can be a gentle way of deterring uninvited visitors.

In addition to that, the difference in height of the plants protects the soil, prevents erosion by wind and heavy rain and can also reduce evaporation on hot summer days. The different root systems loosen the soil in 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: fertilisers with an organic long-term effect are particularly suitable for companion planting.

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 there are some plant combinations that thrive side by side, other plants are terrible neighbours to each other. In the following, we will show you the best companion plants for tomatoes as well as the plants you should not grow next to tomatoes. For further information on plant combinations for companion planting, we recommend you read this 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 good 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 (Petroselinum crispum) and basil (Ocimum basilicum) also keep the annoying aphids away.

Carrots (Daucus carota subsp. sativus) 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 good 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 good companion plants as well. Marigolds grow close to the ground and keep away annoying nematodes. At the same time, because of their flowers, pollinators are drawn to the marigolds, which in turn helps achieve an abundant tomato harvest.

companion plants for tomatoes
Amazingly, flowers, such as marigolds, make wonderful companion plants for tomatoes [ Gavrilchik]

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 really get along. Companion planting tomatoes and cucumbers does 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.

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.

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