14 Vegetables You Should Never Plant Together (2024)

Companion planting is an effective way to repel pests, attract beneficial pollinators, and stimulate healthy growth. But pairing certain vegetables together can also have adverse effects on the plants growing in your garden. Planting incompatible vegetables together can stunt growth, welcome pests and diseases, and negatively impact flavor. To keep your plants happy and healthy, experts say to never grow the following vegetables together.

Use Our Companion Planting Chart to Grow a Thriving Vegetable Garden

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Beans and Onions

14 Vegetables You Should Never Plant Together (1)

Onions and beans should never be grown together due to the allelopathic properties of onions. "Onions emit allicin, an antibacterial gas, which kills the beneficial urease bacteria," says Linda Langelo, horticulture specialist atColorado State University. The urease is what beans need to fix nitrogen. Planting these two vegetables together can inhibit the growth of beans in their early stages, and produce smaller, weaker crops.

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Tomatoes and Potatoes

14 Vegetables You Should Never Plant Together (2)

Tomatoes and potatoes are susceptible to similar pests and diseases, says Carrie Spoonemore, co-creator of Park Seed's From Seed to Spoon app. "Growing these plants in close proximity increases the risk of these issues spreading," she says.

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Corn and Tomatoes

Corn and tomatoes should not be planted together due to their different growth habits. "Both of these plants are heavy feeders and require nutrient-rich soil," says Spoonemore. "When planted together, this increases the competition for vital nutrients and may inhibit the growth and development of the plants." Additionally, tomatoes require full sun to grow and tall corn stalks can shade tomato plants.

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Tomatoes and Brassicas

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Never plant tomatoes and brassicas together as they are both heavy feeders and require nutrient-rich soil to thrive. "Planting these together can lead to greater competition for nutrients and leave tomatoes undernourished, hindering their growth," says Spoonemore.

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Cucumber and Squash

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Cucumbers and squash come from the same family and both need nutrient-rich soil in order to thrive. "Planting cucumbers and squash together increases the competition for vital nutrients and will quickly exhaust the nutrients in their soil," says Spoonemore.

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Lettuce and Celery

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Lettuce and celery should never be planted together because celery can attract pests, including aphids and whiteflies, which increases the risk of infestation of the lettuce and damages both crops.

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Fennel and Tomatoes

Fennel is a poor companion plant for many garden vegetables, but it can especially inhibit the growth of tomatoes. "It’s best to keep fennel away from many of your vegetables," says Spoonemore. "It should be grown in a container so its roots don’t touch surrounding plants."

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Peppers and Cabbage

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Avoid planting peppers and cabbage next to one another, as peppers that are in the nightshade family will have their growth inhibited by the cabbage in the brassica family, says Langelo.

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Potatoes and Zucchini

14 Vegetables You Should Never Plant Together (9)

If planted together, potatoes will utilize available nutrients and starve out the zucchini. "Two fast growers and heavy feeders do not give good results come harvesting time," says Langelo. "Potato tubers will be small if they are not given regular applications of phosphorus and potassium. They will be malformed and will not last as long in storage. Zucchini will have stunted growth."

How to Grow and Care for Potatoes—Including Martha's Favorite Planting Method

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Carrots and Parsnips

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Carrots and parsnips are both in the Apiaceae family, meaning they share pests and diseases. "Placing vegetables in the same family will always bring about a higher risk of a disease or pests," says Langelo. "In this case, carrot root fly can attack both carrots and parsnips." Additionally, growing several root crops in a garden increases the risk of attracting the same pests to one and spreading that pest to others.

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Asparagus and Onions

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Asparagus and onions do not make good companion plants because they are plagued by some of the same pests and diseases, such as cutworms, which destroy asparagus stalks and eat new onion transplants. Additionally, the allelopathic properties of onions can inhibit the growth of asparagus, says Langelo.

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Pumpkins and Summer Squash

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Pumpkins and summer squash will cross-pollinate if grown together. "This produces very odd-looking fruits that do not taste very palatable," says Langelo. Both of these crops also share insects and diseases, including powdery mildew, squash vine borers, hairy back legs, and squash bugs.

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Fennel and Eggplant

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Fennel releases a substance from its roots that can inhibit the growth of other vegetables, especially eggplant. For best results, plant fennel far away from other vegetables or in a container where its roots are contained.

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Peas and Garlic

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Garlic produces sulfur compounds that can stunt the growth of peas, says Langelo. Peas and garlic also compete for the same nutrients in the soil. In addition to peas, garlic also stunts the growth of asparagus, beans, sage, parsley, and strawberries.

14 Vegetables You Should Never Plant Together (2024)


14 Vegetables You Should Never Plant Together? ›

Cucumbers and tomatoes can be planted by each other as they share similar growing habits and therefore you can grow tomatoes by cucumbers. Greg Volente from Greenhouse Today explains that: 'Cucumbers and tomatoes are two vigorous growers in a spring garden. They're both vining plants and share similar basic needs.

What vegetables should I avoid planting together? ›

Examples of Plants That Should Not Be Grown Together
AsparagusFennel, Garlic, Onions, Potatoes
OnionsAsparagus, Beans, Dill, Peas, Sage
PeasChives, Garlic, Onions, Potatoes, Pumpkin
PeppersCabbage, Broccoli, Cauliflower, Fennel, Kohlrabi
21 more rows

What vegetables should not be mixed together? ›

Incompatible Plants (6 Vegetables That Just Don't Go Together)
  • Tomatoes and potatoes. ...
  • Onions and peas. ...
  • Cabbage and strawberries. ...
  • Carrots and dill. ...
  • Cucumbers and basil. ...
  • Fennel and lettuce.
Mar 21, 2022

Can cucumbers and tomatoes be planted together? ›

Cucumbers and tomatoes can be planted by each other as they share similar growing habits and therefore you can grow tomatoes by cucumbers. Greg Volente from Greenhouse Today explains that: 'Cucumbers and tomatoes are two vigorous growers in a spring garden. They're both vining plants and share similar basic needs.

What should you not plant next to cucumbers? ›

Antagonistic plants for cucumbers
  • Plants in the same family as zucchinis, melons and pumpkins should not be planted directly next to cucumbers.
  • The same applies to Jerusalem artichokes, lovage, sage, radishes, radishes and tomatoes.
Apr 11, 2023

What vegetables grow best together? ›

Which Vegetables Grow Well Together?
VegetableCompanion PlantDon't Plant Together
OnionsBeets, carrots, Swiss chard, lettuce, peppersAll beans and peas
PeasBeans, carrots, corn, cucumbers, radish, turnipGarlic, onions
PotatoesBeans, corn, peasTomatoes
SquashCorn, melons, pumpkinsNone
11 more rows
Jun 26, 2021

What vegetables Cannot be put together? ›

  • Keep Onions Away From Apples and Potatoes.
  • Store Melons Solo.
  • Keep Cauliflower Away From Apples, Kiwis, and Onions.
  • Place Mushrooms Away From Pungent Foods.
  • Use Your Crisper Drawer.
  • Separate Ethylene Producers and Ethylene Sensitive Produce.
Aug 5, 2022

What not to plant next to peppers? ›

Basil and nasturtium prevent aphids and whiteflies, onions and garlic help against fungal diseases such as gray mold. You should not plant aubergines, peas, fennel, beet, potatoes and celery next to peppers and chili peppers.

What vegetables mix well together? ›

The Best Vegetable Combinations That Go Well Together
  • Avocado and Spinach: These to taste great paired together and offer plenty of nutrients. ...
  • Broccoli and Cauliflower: They're similarly shaped but taste quite different. ...
  • Carrots and Potatoes.
  • Peppers and Broccoli.
  • Cabbage and Collard Greens.
  • Mushrooms and Broccolini.
Aug 15, 2020

What grows best with peppers? ›

In a raised bed, various herbs such as basil, parsley or dill are good companions for peppers. Lettuce, carrots and onions also make good neighbours for peppers in a raised bed.

Can you plant bell peppers and tomatoes together? ›

Tomatoes. Although it's usually recommended to not plant tomatoes and peppers right after each other in the same bed every year, they can be grown together in the same garden bed (and then rotated to another bed next season).

What not to plant near celery? ›

Don't plant root crops, such as carrots, parsnips, and potatoes nearby. Celery has a shallow root system that can be damaged when a root crop is harvested. Corn is also not a good choice. It is a heavy feeder and can deplete the soil of the nutrients that celery needs, and the tall plants block too much sunlight.

What not to plant with zucchini? ›

Potatoes can also spread diseases such as late blight, which can also affect zucchinis. Cucumbers and pumpkins should not be planted next to zucchinis as they belong to the same family (Cucurbitaceae) and therefore attract similar pests and diseases.

Can peppers and cucumbers be planted together? ›

Vining vegetables like cucumbers actually make perfect companions to bushing veggies like peppers. They enjoy similar growing conditions and can grow together in about the same amount of space as a single plant. Ensure you trellis your cukes and plant your peppers in front so they aren't shaded by growing vines.

Which vegetable combination is not good? ›

Some Useful Tips to Aid Digestion
Nightshades, e.g., potato, tomatomelon; cucumber, dairy products
Radishesbananas, raisins; milk
Tapiocafruit, especially banana and mango; beans, raisins, jaggary
Yogurtfruit; cheese, eggs, fish, hot drinks, meat, MILK, nightshades
9 more rows

What vegetables can sit next to each other? ›

The Bottom Line

“The easiest rule to follow is to just store like produce together,” Grant-Vose says. “Berries can be stored together, brassica vegetables can be stored together, leafy greens can be together, and most root vegetables (except potatoes) can go together.”

What should you not plant peppers next to? ›

There's really no evidence that certain plants will somehow affect pepper growth, but you may want to avoid planting peppers near cabbage and other brassicas such as broccoli and cauliflower (because peppers prefer slightly different soil acidity levels) and fennel (which some gardeners say inhibits pepper development) ...

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