It's hard to overstate the importance of plant relationships for cucumbers. As heavy-feeding vegetables that like a lot of moisture, cucumbers' growing environment can be very welcoming to pests like aphids, beetles, and cabbage loopers. While appropriate plant care is the first line of defense, anything planted as a monoculture-- even in a raised bed-- is likely to suffer.
For cucumbers, companion plants that deter pests, reduce pest populations, or act as a trap crop can mean a massive improvement in both plant health and yields.
This is an overall guide to mitigating pest damage, cultivating a healthier garden, and enhancing growth with cucumber companion plants. While it's not an exhaustive list, these are general guidelines for what types of plants grow well with cucumbers and other cucurbits.
Skip Ahead: Benefits of Companion Planting • The Best Companion Plants for Cucumbers • Bad Companions for Cucumbers • Cucumber Pests • Companion Planting Chart
Benefits of companion planting with cucumbers
Broadly, intercropping allows you to improve cucumber yields through plant partnerships while also balancing out pest populations and attracting more pollinators. But before we get into how companion plants can improve your cucumber harvest, here are a few benefits of using cucumbers as companion plants:
- Providing shade: Cucumbers grown on trellises can cast significant shade for cool-weather loving plants like parsley, cilantro, and chives.
- Covering soil: Cucumbers need a lot of water to grow, but they can also improve soil's moisture retention by shading it from the sun.
- Maximizing yields: Cucumbers grow a long taproot, followed by shallower feeder roots. Interplanting them with some root crops can actually improve yields for both plants because they won't be competing for nutrients in the soil.
- Improving soil condition: Most vegetables will improve soil condition just by sending out roots, but cucumbers' long taproots can draw up nutrients and aerate the soil down to two or three feet.
The best companion plants for cucumbers
Plants that grow well with cucumbers usually enjoy full sun, very rich, loamy soil, and regular, heavy watering. A few good cucumber companions don't thrive in full sun, but can benefit from the shade cast by cucumber leaves.
In practice, this means you'll have the most success growing cucumbers next to other heavy-feeding vegetables, herbs that like partial sun, and a few summer annuals. However, there are a few exceptions; some aromatic herbs and vegetables can negatively affect cucumber flavor. On a similar note, other cucurbits will struggle to grow with cucumbers and may encourage colonization by pests.
Here are a few tried and true cucumber companions:
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1. Peas
Shelling peas, snow peas, and snap peas companion planted with cucumbers can all maximize space while improving the soil. They also share cucumbers' growing requirements of full sun, loamy soil rich in organic matter, and regular watering. Provided they have sufficient space and nutrients, they'll happily grow up a trellis next to cucumbers.
For planting in rows, space cucumbers 10 to 12 inches apart and space peas about three inches apart. Alternatively, you could grow cucumbers horizontally, shading the soil, and grow the peas up trellises.
Keep in mind that sweet peas are cool season flowers that won't grow well in mid-summer. They can be planted in a trellis space in advance of cucumbers, but their growing window has little overlap with cucumbers.
2. Beans
Like peas, beans are thirsty and hungry plants that enjoy the same conditions as cucumbers. Pole beans spaced four to six inches apart will happily grow up a trellis next to or above cucumbers. Bush beans can provide shade at the base of trellised cucumber plants, helping the soil to retain its moisture. As with peas, give the soil plenty of organic matter and composted manure prior to sowing or planting.
3. Radishes
Radishes are fantastic companion plants for cucumbers and squashes. Research shows that radishes repel cucumber beetles, attract parasitic wasps and improve squash yields, and can grow as a trap crop for flea beetles. They can also grow as a catch crop at the base of cucumber plants to maximize your planting space.
Radishes will benefit from cucumber's regular waterings, as dry soil causes radish stems to go woody. Keep in mind that cucumbers need a lot of nutrition, while radishes grown in excessively nitrogenous soil will grow a mass of leaves and underdeveloped roots. A solution is to amend the soil deeply, encouraging cucumbers' long tap root to grow.
4. Corn
Corn patches provide a ready-made trellis for dwarf and pickling varieties of cucumber. Companion planting corn and cucumbers can be an effective use of space, but both plants are heavy feeders. To ensure they'll both grow happily, amend the soil generously with compost when planting and keep an eye out for signs of nutrient deficiency throughout the season.
5. Tomatoes
Tomatoes and cucumbers share the same growing requirements, so it's easy to take care of them when they're side-by-side. That said, growing cucumbers and tomatoes together requires a lot of space and a lot of added nutrition in the soil. Before planting, heavily amend the soil with compost. Regularly pruning the tomatoes and keeping the cucumbers trellised will allow for adequate sun and airflow.
To give both plants enough space, grow them vertically and place each plant 18 to 24 inches apart.
Tomatoes and cucumbers attract many of the same pests, so they may also benefit from interplanting with a companion that helps diminish or deter predators. A few particularly good options are marigolds, parsley, or cilantro.
Read More: The 11 Best Companion Plants for Tomatoes
6. Peppers
Companion planting peppers with cucumbers can make good use of limited space, as long as the cucumbers are trellised or trained so as not to shade out the pepper leaves. Both plants will benefit from rich, loamy soil, intense sun, and consistent watering.
Read More: How to Grow Peppers from Seed to Harvest
7. Dill
Planting dill near your cucumbers can help with cucumber beetles, as dill attracts the predatory insects and parasitic wasps that prey on them. While mature dill plants can actually inhibit the growth of some vegetables (namely nightshades), that isn't the case for cucumbers.
Read More: The 10 Best Companion Plants for Dill
8. Parsley
Parsley is a versatile herb in the carrot family, along with dill and cilantro, that's fantastic for attracting predatory insects like hoverflies, lacewings, ladybugs, and parasitic wasps and flies. All of these insects can help cucumbers with pest damage from beetles, aphids, mites, and caterpillars.
Plant parsley in the shade cast by cucumber plants to help it avoid bolting during the hottest weeks of summer.
Read More: The Best and Worst Companion Plants for Parsley
9. Cilantro
Cilantro offers many of the same benefits for cucumbers as parsley and dill: beneficial insects and less pest damage. As a cool weather plant, cilantro may only have a few weeks of overlap with cucumbers at the beginning and end of summer. To extend your harvest window, plant cilantro in cucumber's shade and keep both plants well watered.
Read More: The Best and Worst Companion Plants for Cilantro
10. Chives
Alliums are some of the best herbs for 'repelling' pests, as their strong aromas mask the scent of other plants. Unfortunately, most alliums aren't good companions for cucumbers because that strong aroma can actually affect the cucumbers' flavor. Fortunately for the organic gardener, chives meld the best of both worlds.
Chives are ideal for pairing with cucumbers because they repel cucumber beetles, thrive in the same soil conditions, and can maximize space by growing in the shade of trellised cucumbers. In fact, most summer vegetables could benefit from companion planting with chives, including tomatoes, peppers, carrots, and onions.
11. Marigolds
Marigolds are some of the best companion flowers for a vegetable garden, offering a long list of benefits to a range of plants. Planting marigolds and cucumbers together can help reduce damage from aphids and flea beetles, as well as cut back on whitefly damage. Marigolds also support parasitic wasps that prey on stink bugs.
Read More: The 16 Best Companion Plants for Marigolds
12. Nasturtium
Nasturtium can be useful as a trap crop for aphids and nematodes, but they can also help to reduce whitefly populations. As with any sacrificial trap crop, let them become established before planting your main crop and plant them some distance from the plant you want to protect.
13. Tansy
Though not a very popular flower for vegetable gardens, research shows that tansy can repel cucumber beetles. Tansies are also adaptable, undemanding flowers, and they can cope with partial shade cast by growing cucumber leaves.
14. Sunflowers
Like corn stalks, strong sunflowers can provide a vertical support for pickling cucumbers and other small cucumber varieties. Alternatively, you could create another variation on the 'three sisters' combination with beans and cucumbers: plant pole beans to grow up the sunflower stalks and plant cucumbers at the base to shade the soil.
However you plant them, both sunflowers and cucumbers are heavy feeders, so give them a place in rich, loamy soil and full sun.
15. Zinnias
Zinnias are a useful trap crop for cucumber beetles, as long as the flowers bloom before the cucumbers can attract the beetles. They'll grow well in full sun and rich soil, but they should be planted some distance away from your cucumbers. In fact, growing zinnias in pots around your cucumber patch is an ideal way to draw pests away from the vegetables.
Read More: The 9 Best Zinnia Companion Plants
Bad companion plants for cucumbers
The list of plants that won't grow well with cucumbers is much longer than the list of plants that will, as it includes almost entire families of vegetables. But as with any garden advice, these are not hard and fast rules. In fact, some of these plants, like rosemary and mint, are great to keep near cucumbers as they deter pests, but they wouldn't do well planted in the soil next to cucumbers.
Overall, interplanting increases biodiversity and benefits the garden. But if you're thinking of putting something right next to cucumbers in the soil, here are some plants to avoid:
- Cucurbits (watermelons, melons, pumpkin, squash)
- Mediterranean herbs (rosemary, sage, thyme, oregano)
- Potatoes
- Onions
- Garlic
- Mint
- Fennel
1. Brassicas
As a general rule, brassicas don't thrive when planted alongside main season crops like cucumbers, tomatoes, and other fruiting vegetables. This is largely because brassicas benefit from soil that has not been recently amended-- too much nitrogen in the soil can actually weaken brassica plants, encouraging pests to move in.
Instead of using them as companion plants, incorporate brassicas like kale, cabbage, cauliflower, and broccoli into a crop rotation. They'll do much better in the depleted soil that's just been evacuated by cucumbers.
2. Cucurbits
Planting squash and cucumbers together is generally not a good idea, and the same applies to all other cucurbit family plants, including watermelons, melons, luffas, gourds, and zucchini. All of these vining plants will struggle to get adequate light, water, and nutrients when planted together.
3. Mediterranean herbs
In addition to affecting flavor, Mediterranean herbs like rosemary and sage won't enjoy the super rich soil and heavy waterings that cucumbers need. They're still worth keeping nearby in pots, though, as these are some of the best companions for deterring pests.
Read More: The 11 Best Companion Plants for Rosemary
4. Potatoes
Growing potatoes with cucumbers will cause both plants to struggle for the root space and nutrients they need. Instead of planting them with cucumbers, consider other potato companion plants like peas, beans, corn, or radishes.
5. Onions
Onions can grow well next to cucumbers, but they may affect the cucumbers' flavor. They would make an efficient use of space and would likely deter pests-- onions' strong scent confuses aphids-- but other cucumber companions do the same without impacting flavor.
Read More: The 20 Best Companion Plants for Onions
5. Garlic
Garlic is also a bad companion for cucumbers, thanks to its strong aroma. But the more concerning factor is that garlic, onions, and leeks are susceptible to bulb rot when the soil is kept too moist. This is a particular risk later in the season when the bulbs are nearly ready to harvest-- which is exactly when cucumbers need more water to produce fruit.
6. Mint
As with other aromatics, planting mint with cucumber can affect the fruit's flavor. Mint comes with the added detriment of spreading like a weed, which enables it to choke out nearby plants. There are quite a few plants that benefit from having mint nearby, but it's best in its own pot.
Read More: The 13 Best Companion Plants for Mint
7. Fennel
Finally, fennel is a fantastic herb worth well growing for it bulbs and the beneficial insects it attracts. But it also releases a chemical in the soil that actively suppresses the growth of many other plants, including cucumbers.
Common cucumber pests
Cucumbers attract some of the same pests as tomatoes, peppers, and other cucurbit plants. These include:
- Cucumber beetles
- Aphids
- Cabbage loopers
- Cutworms
- Spider mites
- Flea beetles
- Thrips
- Whitefly
The first line of defense against any garden pest is to grow a healthy plant; giving your cucumbers full sun, plenty of of organic matter in the soil, and regular waterings will go a long way.
Unfortunately, even the healthiest plants will inevitably struggle with some pests and diseases when planted in isolation. Any of the cucumber companions on this list will help to reduce the likelihood of serious pest damage, as biodiversity in the garden is itself a strong defense. Some particularly helpful companions for deterring pests are marigolds, radishes, and nasturtium.