Any bad companion plants for cucumbers around in your garden can ruin your experience if growing cucumbers is in your plans. To get the best results, you need to know which companion plants to avoid.

Bad Companion Plants for Cucumbers

Some plants are beneficial companions for cucumbers, even deterring pests and inviting beneficial insects to the field. But in this article, we’ll discuss eight plants to avoid when developing your cucumbers.

👩🏻‍🎓 Scientific Reference

“Cornell University indicates that companion planting enhances biodiversity, leading to more balanced insect populations.” Cornell University Research

Bad Cucumber Companion Plants List- Stay Away From These

When it comes to cucumber companion planting, it is important to remember that not all plants are compatible. These plants can include common plants like potatoes, mint, and sage. 

Companion planting is a gardening technique that involves growing two or more plants side by side to benefit each other. It has been used for centuries, and it is still a popular way to naturally balance a garden’s ecosystem.

There are many benefits to companion planting. It can help to attract beneficial insects, such as ladybugs and bees, which can help to pollinate your plants and protect them from pests. Companion planting can also help to increase yields by providing plants with the nutrients they need. It can also help to reduce pest problems, as some plants can repel pests, such as cucumber beetles and bugs.

This method can also help to improve soil health. By rotating crops, you can help to replenish the soil with essential nutrients and prevent nutrient depletion. 

1. Potatoes

Potatoes and cucumbers aren’t friendly companion

Growing season April to June
Distinguish characteristics 
  • Spirally arranged
  • Compound leaves
  • Purple flowers, with yellow stamens
Specific needs
  • moist but well-drained, sandy soil
  • Ph of 6.0 to 6.5
Common pests 
  • Common scab, early blight
  • Grubs, weevils, wireworms

The potato plant is a staple crop for human beings and has been cultivated for centuries. Potatoes are a cold-season vegetable used in many different cuisines across the globe and in many different ways! These potato plants are grown for their nutritious, delicious, and starchy tubers.

Potato vines are bushy plants that grow around 18 inches tall and around the same in width. These will perform best in fertile and slightly acidic soils which will reduce the likelihood of scabs. Before planting your potatoes, you should use well-balanced manure or fertilizer in a worked hole. Depending on the variety, potatoes take around 100 days from planting to being harvest-ready.

There are a plethora of varieties of potatoes developed from their early discovery to their worldwide recognition and international stardom! But why are they such a bad side crop for cucumbers?

Potatoes and cucumbers aren’t friendly companion plants and are generally considered incompatible in the garden.

They can cause harm to each other if planted in the same patch of ground. Cucumbers and potatoes are both heavy feeders, and they will both struggle and fight for precious minerals and vitamins!

Cucumbers and potatoes won’t be protecting each other from pests and diseases too! Potatoes can be attacked by slugs, wireworms, eelworms, nematodes, and whole heaps of cucumber beetles. Potatoes bring a lot of diseases too — scabs, blight, rot, and stem canker can all transfer themselves from potatoes to your cucumber plants!

2. Sage

Sage hinders cucumber’s growth and flavor

Growing season Spring And Summer
Distinguish characteristics 
  • Tall perennials
  • White and silvery green foliage
  • Pleasant smell
Specific needs
  • well-drained soil
  • Full sun
Common pests 
  • Slugs, Beetles
  • Root rot, wilt

Sage is grown for its beautiful silver-white foliage. It is a fast-growing perennial that spreads pretty fast, adding light and adorable contrast to the overall landscape design. It grows perfectly well with almost anything in your garden except alliums and cucumbers.

Sage is growing in bushy clumps on its patches of land, and the foliage is dashingly aromatic when scratched. The leaves are wooly on the underside and glabrous at their top sides.

Sage grows up to three feet tall and thrives in moderately fertile and sandy to poor soils and in full sun. In some climates, this plant will self-spread rather aggressively and can become a nuisance. It spreads by both rhizome activity and seeds. Sage is a beautiful addition to herb and flower beds and borders and is a great companion planting in your vegetable garden — as long as you don’t plant it next to cucumbers or alliums!

Although sage is a good companion for many vegetable garden plants, it won’t do well with your cucumbers as cucumber isn’t exactly a fan of herbs. Other herbs that don’t go well with cucumber include basil and mint. Sage hinders cucumber’s growth and flavor. If you don’t want your cucumbers to have a sagey-like taste, avoid planting them too close.

Cucumbers will require a lot more water than the sage plant, which thrives in dry conditions.

If grown in well-drained soil, sage will rarely have pest issues, but combined with the moist environment of cucumbers, it will attract slugs, bugs, root rot, and wilt, which will all affect and damage your cucumber plantings. You should also watch out for powdery mildew, which can easily spread to other plants in the vicinity.

3. Mint

not grow cucumbers next to Mint

Growing season Summer, Fall
Distinguish characteristics 
  • Short, bushy perennials
  • Scented leaves
  • Attracts birds and butterflies
Specific needs
  • Well-drained, medium moist soil
  • Full sun
Common pests 
  • Mildew
  • No serious pest issues

Mint is a short perennial with flowers similar to that of lavender plants. It makes for a perfect addition to your garden as a natural pest deterrent. Its bushy foliage comes in clumps of scented leaves, on top of which you get these sets of beautiful purple flowers. This plant is appreciated spice for teas, salads, often soups, and of course – mojitos! You can plant mint in any climate, but it does best in zones three to eight.

Mint plants usually grow up to 16 inches tall, with aromatic leaves exuding a minty scent when crushed or squeezed. They are easily growing in dry and medium moist soils accompanied by full sun. They are drought-tolerant plants that will require some watering in extreme conditions.

Mint will attract more than a few birds, butterflies, and beneficial pollinators, but no matter where you plant it, just don’t let it be near your cucumbers.

Mint herb is highly invasive, and it spreads vigorously, denying plants space and keeping them from spreading.  This makes them poor cucumber companions. Mint is better grown in pots where you can control their growth, allowing your cucumbers some space to live. Similar to watermelons, cucumbers are full of water, and the mint will deny them the ability to take all those nutrients needed to develop that beautifully grown fruit.

When grown in moist soils, mint can also develop mildew problems which will negatively impact your cucumbers and other cultures too! You shouldn’t grow cucumbers next to this one.

4. Basil

avoid planting Basil near Cucumbers

Growing season Spring to Fall
Distinguish characteristics 
  • Herb, perennial
  • Glossy, scented leaves
  • Easy growing
Specific needs
  • Fertile, moist soils
  • Full sun
Common pests 
  • Mildew
  • Slug, snails

Having a worldwide reputation, basil is one of the easiest herbs you can grow in your garden. Its leaves are used fresh and dried to flavor any kind of meal, ranging from fish, meats, salads, and sauces. Basil is similar to mint, and it belongs to the same family of plants. Most varieties are short-lived perennials thriving in warmer climates.

Basil is usually ready to harvest within 90 days of planting, depending on the variety. Basil plants grow up to 30 inches tall and about 20 inches wide. They perform best in fertile soils and are extremely frost sensitive. They are a valuable addition to any vegetable garden and are perfect companions to lettuce, parsley, beans, beets, cabbage, marigolds, potatoes, and oregano.

However, you should avoid planting them near sage plants and cucumbers!

Just like with the mint herb, basil is invasive, and it will spread vigorously, denying your cucumbers space and keeping them from spreading their vines —as such, a poor cucumber companion. Basil is also better grown in pots where you can control its growth and allow your cucumbers a space to live.

Basil will deny cucumber plants the ability to take all those nutrients needed to develop their fruits. When grown in moisture-rich soils, basil can also develop mildew problems which will negatively impact your cucumbers and other water-loving plants! Basil can also attract slugs, snails, and other pesky insects.

5. Fennel

keep Fennel out the cucumber way

Growing season Summer, fall
Distinguish characteristics 
  • Perennial
  • Tall stems, yellow flowers
  • Parsley-like leaves
Specific needs
  • Fertile, moist soils
  • Full sun
Common pests 
  • No serious pest and disease issues
  • Aphids, stem rot

Fennel plants are ridiculously aromatic perennials with feathery and finely divided aromatic leaves and large umbels of tiny yellow flowers on top of tall stems. Blooming in the high summer heat, these flowers will attract butterflies and, after pollination, will give way to aromatic fennel seeds.

Fennel is also grown for its delicious bulbs. While fennel adds some flavor to salads and various dishes, it has some health benefits too!

These plants grow up to six feet high and around three feet wide. They prefer rich and moist soils and full sun conditions. They are incredibly easy to grow and are a great addition to most flower and herb beds and wildlife gardens! As long as you keep them out the cucumber way.

Fennel is a natural flea repellent and will improve your overall pest control in the garden. Fennel should not be found with most crop-bearing plants inside the garden. Its presence in the garden can look harmless, especially because it attracts beneficial insects. Until it begins to hinder their growth, that is. In the process of cultivating them, fennels could even kill your cucumbers.

6. Pumpkins

Cucumbers won’t have a pleasant time next to Pumpkins

Growing season Summer, fall
Distinguish characteristics 
  • Vining plants
  • Big leaves
  • Big squashy fruits
Specific needs
  • Fertile, moist soils
  • Full sun
Common pests 
  • Powdery mildew
  • Squash bugs and beetles

Pumpkin vine plants are sprawling vines with yellow flowers native to the Western hemisphere. The yellow flowers give way to large squash fruits, most commonly referred to as pumpkins, but there are a ton of varieties you can find out there! The fruits of squash plants have a mild flavor and have a large number of applications in cuisines across the world.

To maximize the growth of squash plants, you can add some compost in the fall and look to maximize soil moisture for the next growing season. Almost all plants of the pumpkin family are easily grown from seeds and are quick and vigorous growers with sprawling vines all over the place.

Cucumbers won’t have a pleasant time next to other vining plants, and this holds especially true for pumpkins. Your cucumbers need plenty of sunlight and space to grow properly and vigorously, which pumpkin plants will relentlessly fight them for.

Pumpkins are also disease and pest bearers for the cucurbit family — squash bugs, vine borers, beetles, worms, whiteflies, aphids, and spider mites will all happily spread to cucumber vines.

Both cucumbers and pumpkins won’t be able to handle diseases. Powdery mildew, leaf spots, or root rot are the most usual ones, and they will surely exchange them when grown next to one another.

7. Brassica Family

Brassicas are like decoys to cucumbers

Growing season Summer, fall
Distinguish characteristics 
  • Leafy, dark-green vegetables
  • Fast growing
  • Nutritious leaves
Specific needs
  • Fertile, moist soils
  • Full sun
Common pests 
  • Nematodes, snails, maggots
  • Rot, leaf spot, blisters

The Brassica family of plants include vegetables such as kale, cabbage, and other green, leafy sprouts. They are cool-season vegetables grown for their nutritious and edible leaves. These come in various shapes and sizes for around-the-year harvesting regimes. Cabbage especially has a wide range of culinary uses and healing properties.

Brassica plants grow anywhere up to 24 inches tall and 30 inches wide. Cabbage and others in the group perform best in full sun and organically rich soils that need to be constantly moist, and with pH levels of 6.0 to 6.8. Depending on the variety, these plants take around 100 days to be harvest ready.

These plants are generally considered to be heavy feeders and shouldn’t be planted next to other plants to avoid nutrient wars in the garden!

Brassicas are like decoys to cucumbers. Growing brassicas with cucumbers is a highly controversial topic, as some gardeners consider them to be great companions. But growing these together can only cause harm to both.

They will compete with cucumbers for everything, depriving them of much-needed nutrients and the fight will end in poorly grown fruits.

The Brassica family is also susceptible to a variety of pests, such as cabbage worms, aphids, loopers, maggots, flies, snails, and nematodes. There are also quite a few diseases such as rot, leaf spot, and blisters, all of which can damage cucumbers severely!


Companion planting can be a great way to improve the health and productivity of your garden. When it comes to cucumber companion plants, it is important to remember that not all plants are compatible.

  • It is best to avoid planting cucumbers next to fennel, sage, mint, basil, and pumpkins.
  • Good companion plants for cucumbers include dill, legumes, marigolds, and sunflowers. Basically, anything that will attract pollinators and not steal nutrients.
  • Planting compatible plants can help to reduce the spread of diseases and improve air circulation, which can help to keep your plants healthy.

By following these tips, you can ensure that your cucumber plants will be healthy and productive.

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