16 Plants You Should Never to Grow Next to Tomatoes

Tomatoes are a beloved garden staple, but did you know that avoiding certain plants is important for growing healthy, productive tomatoes?1

From common vegetables to herbs and even some fruits, these 16 incompatible plants can stunt growth, spread diseases, or compete for valuable resources.

By understanding which plants to keep separate, your tomato plants will thrive and produce a bountiful harvest. 

1. Potatoes

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Potatoes and tomatoes, while both staples in many home gardens, don’t make great companions due to a few important factors. Both plants belong to the nightshade family, Solanaceae, meaning they’re susceptible to the same diseases and pests (ref). 

Planting them together could create an open invitation for harmful pathogens and critters, putting your crops at risk. These two plants also have similar nutrient needs, which means they could end up competing for resources in the soil.

2. White Mustard

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While white mustard can be a helpful cover crop, reducing pesky soil-borne pathogens like verticillium wilt, there’s a catch. Tomatoes grown with white mustard produce fewer fruits, both early in the season and overall.

White mustard’s natural properties can release compounds that might hinder tomato growth and germination, leading to smaller yields. Both plants might end up competing for vital resources, making it even harder for your tomatoes to thrive.

3. Cabbage

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Cabbage and tomato plants have different nutrient needs, and when planted together, they compete for the same nutrients in the soil. 

Cabbage roots are aggressive and can damage the delicate root systems of tomato plants, further hindering their growth. It is best to avoid planting cabbages and tomatoes near each other to ensure healthy and thriving plants.

4. Broccoli

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Broccoli is part of the cabbage family (brassicas) and is not recommended to be planted near tomatoes since they will compete for nutrients and space.

Cabbage releases chemicals from their roots that can inhibit the growth of tomatoes. These chemicals are called allelochemicals, and they can stunt the growth of nearby plants (ref).

5. Cauliflower

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Cauliflower is yet another brassica that can negatively impact tomato growth. 

Cauliflower is a heavy feeder that soaks up lots of nutrients, while tomatoes have their own specific requirements. This mismatch can lead to a tug-of-war for resources, leaving both plants struggling to thrive.

7. Brussels Sprouts

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Brussels sprouts and tomatoes both have healthy appetites for nutrients in the soil. This can lead to some intense competition, resulting in stunted growth and reduced yields. 

Both plants can also be susceptible to similar diseases and pests. Brussels sprouts also prefer cooler temperatures, while tomatoes thrive in the warmth – a tricky balance to strike in one veggie patch.

8. Rutabagas

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Rutabagas are root vegetables that should be avoided near tomatoes. Both plants are heavy feeders, meaning they require lots of nutrients from the soil. This competition can result in stunted growth and less harvest for both veggies.

Tomatoes and rutabagas also share a vulnerability to certain diseases and pests. Planting them together may put your garden’s health at risk.

9. Turnips

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Turnips are also root vegetables that can negatively impact tomato growth. Both plants have similar growth requirements and attract common pests, such as flea beetles and root maggots. 

When planted closely, competition for nutrients, water, and sunlight may occur, and pest populations can increase, leading to stunted growth and potential crop damage.

10. Eggplant

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Eggplant is a member of the nightshade family, just like tomatoes. Planting them too close together can spread diseases between the plants. 

Eggplant also produces a chemical called glycoalkaloid that can stunt tomato growth (ref).

11. Corn

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Corn is a tall, fast-growing plant, while tomatoes are lower-growing and more bushy. This difference in growth habits can make it challenging to manage and harvest both crops efficiently when planted together.

Corn also has a deep root system that competes with tomatoes for water and nutrients. 

12. Dill

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As dill matures and begins to seed, it can inhibit the growth of nearby tomato plants and negatively impact their health and overall yield. 

While young dill plants may initially help repel certain pests, such as aphids, their presence ultimately becomes detrimental to tomatoes as they grow and develop.

13. Fennel

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Planting fennel and tomatoes together is not recommended due to fennel’s allelopathic properties. 

These properties release toxins into the soil and inhibit the growth of nearby plants, including tomatoes. Fennel also has a deep taproot that competes for resources.

14. Pole beans

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Pole beans require huge amounts of nutrients from the soil. When planted with tomatoes, they may compete for these nutrients. This leads to nutrient deficiencies and stunted growth.

Pole beans also need a sturdy trellis or support system to climb, which can lead to overcrowding when planted with tomatoes.

15. Okra

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Okra’s tall and leafy growth habit can block the sunlight tomatoes need for optimal growth. 

Also, okra’s susceptibility to nematodes may lead to an increase in nematode populations in the soil, which can negatively impact tomatoes planted in the same area.

16. Blackberry Bushes

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Blackberry plants grow vigorously, which can potentially harbor pests like spider mites, aphids, and fruitworms. These pests can easily transfer to nearby tomato plants, causing damage and reducing the overall yield of tomatoes. 

Plus, blackberry bushes are perennial plants with deep root systems that can compete with tomatoes for water and nutrients.

Avoiding these 16 plants that can hinder tomato growth can create a healthier and more productive garden. Remember to plan your garden layout carefully. Keep in mind the interactions between different plant species so you can cultivate a thriving tomato garden that yields delicious and abundant harvests.

Source:

  1. https://www.tandfonline.com/doi/abs/10.1080/14620316.2008.11512427
nancy
Author & Editor | + posts

Nancy has been a plant person from an early age. That interest blossomed into a bachelor’s in biology from Elmira College and a master’s degree in horticulture and communications from the University of Kentucky. Nancy worked in plant taxonomy at the University of Florida and the L. H. Bailey Hortorium at Cornell University, and wrote and edited gardening books at Rodale Press in Emmaus, PA. Her interests are plant identification, gardening, hiking, and reading.