Maximize Your Onion Harvest with Companion Plants

Are you looking to improve the health and productivity of your onion crop while also fostering a dynamic and diversified garden ecosystem? Onion companion plants offer a natural and effective way to achieve these goals. 

By carefully selecting plants that complement and support onion growth, you can improve soil fertility, discourage pests, and promote positive interactions between species. In this article, we’ll delve into the realm of onion companion plants, specifically the finest partners to grow alongside your onions for the greatest outcomes.

What Is Companion Planting?

Companion planting is a gardening strategy in which many plant species are cultivated together to maximize their benefits and assist one another’s growth. This strategy is founded on the concept of symbiosis, in which plants interact to improve their general health and output.

Gardeners may establish a balanced and biodiverse ecosystem by carefully selecting companion plants that support natural pest control, soil fertility, and overall garden resilience.

Companion planting also considers the specific needs and growth habits of several plant species. Gardeners can ensure that each plant flourishes in its environment by pairing them with plants that have similar requirements, such as water and sunlight. 

Benefits Of Onion Companion Plants

Onion companion planting provides several benefits that contribute to the overall health and productivity of the garden. Here are some of the key advantages:

Pest Deterrence: Onions exude natural substances that deter a variety of pests, including aphids, carrot flies, and cabbage worms. Gardeners can establish a protective barrier that deters pests and minimizes the chance of pest damage by interplanting onions with susceptible crops, without using chemical pesticides.

Enhanced Flavor and Growth: When cultivated alongside onions, certain companion plants can boost both the flavor and growth of the onion crop. For example, growing onions alongside carrots is a traditional companion planting combination known as a “carrot fly deterrent.” The strong perfume of onions masks the smell of carrots, making it difficult for carrot flies to find their preferred host plants.

Soil Improvement: Onions are part of the allium family, which also includes garlic, leeks, and shallots. These plants are known for their ability to promote soil health by producing chemicals that kill dangerous soil-borne diseases and prevent weed growth. Furthermore, onions have shallow roots, allowing them to cohabit happily with deeper-rooted crops without competing for resources.

Space Optimization: Onions have a smaller footprint than other vegetable crops, making them perfect for interplanting with larger plants like tomatoes, peppers, and squash. Gardeners can maximize garden area and output by nestling onions between larger plants.

Culinary Benefits: Aside from their role as insect deterrents and soil improvers, onions have culinary benefits when planted with other crops. Their aromatic foliage masks the scent of nearby plants, making it difficult for pests to find their favorite hosts. Furthermore, onions can be collected throughout the growing season, ensuring a consistent supply of fresh produce in the kitchen.

Overall, onion companion planting is an effective approach that uses onions’ inherent characteristics to promote healthy growth, discourage pests, and improve soil fertility. You can get more information about companion planting by reading this guideline.

Read Also: Best Sweet Potato Companion Plants For Your Garden

10 Companion Plants To Grow With Onions

When it comes to growing onions, choosing the right companions can make all the difference in promoting healthy growth and maximizing your garden’s potential. Let’s delve into some fantastic companion plants that pair perfectly with onions.

1. Beets

Beets make excellent companions for onions. Beets have shallow roots that won’t compete with onions for space or nutrients even they can help deter pests like aphids, which are often attracted to onions. They also help loosen the soil, making it easier for onions to grow.

Beets Plant
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Planting: Plant beets alongside your onions, either in the same row or in alternating rows.

2. Spinach

Spinach is another great companion for onions. Spinach is a fast-growing crop that can be harvested before the onions start to take up too much space. It also helps to suppress weeds and retain moisture in the soil.

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It has shallow roots that won’t interfere with onion growth, and together, they create a harmonious balance in the garden bed.

Planting: Plant spinach around the base of your onion plants, or sow it in between rows of onions.

3. Brassicas

Brassicas, such as cabbage, broccoli, and kale, are susceptible to pests that onions repel. Planting them together can help to protect both crops.

Cabbage Plant
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They help repel pests like cabbage worms and aphids, which can also attack onions, thus promoting a healthier garden ecosystem.

Planting: Plant brassicas around the perimeter of your onion bed, or interplant them with your onions.

4. Tomatoes

Tomatoes and onions are like a dynamic duo in the garden. While they have different growth habits, they complement each other well. 

Tomatoes Plant
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Tomatoes provide shade for the soil, helping to retain moisture and prevent weeds, while onions can help deter pests that commonly afflict tomatoes, such as aphids and whiteflies. They also improve the flavor of tomatoes.

Planting: Plant onions around the base of your tomato plants, or interplant them with your tomatoes.

5. Peppers

Peppers are excellent companions for onions because they have similar soil and sunlight requirements.

Bell Peppers Plant
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Additionally, onions can help deter pests like aphids and onion flies that might otherwise damage pepper plants. Peppers benefit from the same pest-repellent qualities that onions offer to tomatoes

Planting: Plant onions around the base of your pepper plants, or interplant them with your peppers.

6. Eggplant

This glossy purple vegetable(Eggplant) loves the company of herbs like basil and thyme. They not only add a fragrant touch to your garden but also help deter pests like spider mites and aphids.

Eggplant Plant
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Marigolds are another great companion, with their vibrant blooms attracting beneficial insects while repelling unwanted pests.

Planting: Plant both eggplants and onions in full sun, about 18 inches apart. Eggplants prefer warm soil, so wait until the danger of frost has passed before planting. Space eggplant plants 2-3 feet apart.

7. Strawberries

Strawberries are happiest when nestled among companions that can help suppress weeds and retain moisture, such as thyme or oregano.

Strawberries plant
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They also thrive alongside beans, which fix nitrogen in the soil, providing a natural fertilizer for the strawberry plants.

Planting: Plant strawberries in full sun, about 12 inches apart. Space onion plants 4-6 inches apart. You can plant onions between rows of strawberries or around the perimeter of your strawberry patch.

8. Potatoes

Strawberries are happiest when nestled among companions that can help suppress weeds and retain moisture, such as thyme or oregano.

Potatoes Plants
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They also thrive alongside beans, which fix nitrogen in the soil, providing a natural fertilizer for the strawberry plants.

Planting: Plant potatoes in full sun, about 12 inches apart and 4-6 inches deep. Space onion plants 4-6 inches apart. You can plant onions between rows of potatoes or around the perimeter of your potato patch.

9. Lettuce

Lettuce enjoys the shade provided by taller companions like tomatoes or beans. This shade helps prevent lettuce from bolting prematurely in hot weather.

Lettuce Plant
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Furthermore, planting lettuce alongside onions or garlic can help deter pests like aphids and slugs.

Planting: Plant lettuce in full sun, about 6 inches apart. Space onion plants 4-6 inches apart. You can plant lettuce between rows of onions or around the perimeter of your onion patch.

10. Carrots

Carrots have a special affinity for companions that help loosen the soil, such as radishes. Planting radishes alongside carrots not only helps break up compacted soil but also acts as a natural pest deterrent.

Carrot Plant
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Carrots also benefit from the presence of aromatic herbs like rosemary or sage, which can help repel carrot flies.

Planting: Plant carrots in full sun, about 2 inches apart and 1/4 inch deep. Space onion plants 4-6 inches apart. You can plant onions between rows of carrots or around the perimeter of your carrot patch.

Read Also: Best Blueberry Companion Plants For Your Garden

What Should Not Be Planted With Onions?

When it comes to companion planting with onions, there are certain plants that should be avoided to ensure the success of your onion crop. Here’s a list of what should not be planted with onions:

Peas: Peas are nitrogen-fixing plants that have conflicting soil requirements with onions. Planting peas near onions can lead to competition for nutrients and reduced growth for both crops.

Beans: Similar to peas, beans are nitrogen-fixing plants that may compete with onions for soil nutrients. Planting beans near onions can result in stunted growth and reduced yields for both crops.

Asparagus: Asparagus and onions have different growth habits and soil requirements, making them incompatible companions. Asparagus has deep roots that can interfere with the shallow root system of onions, leading to competition for resources and reduced yields for both crops.

Sage: While sage is not as commonly mentioned as the other three, it’s generally recommended to avoid planting sage near onions. Sage has strong aromatic oils that can inhibit the growth of nearby plants, including onions. Additionally, sage prefers drier soil conditions compared to moisture-loving onions, which may lead to stress for both plants if planted together.

By avoiding planting peas, beans, asparagus, and sage near onions, you can ensure that your onion crop thrives and remains free from competition for resources, resulting in a healthier and more productive garden overall.

Tips For Onion Companion Planting

Here are some additional things to keep in mind when planting companion plants:

Sunlight: Make sure that all of your companion plants have the same sunlight requirements as your onions.

Spacing: Don’t plant your companion plants too close to your onions, as this could compete for space and nutrients.

Watering: Water your companion plants according to their needs, as some may require more or less water than onions.

With a little planning, you can use companion planting to create a healthy and productive garden for your onions and other vegetables.


Can I plant onions with all types of vegetables?

While onions make great companions for many vegetables, there are some exceptions. It’s best to avoid planting onions near beans, peas, and asparagus, as these crops have conflicting soil requirements or may compete with onions for nutrients. 

However, onions generally thrive alongside a wide variety of vegetables, including tomatoes, lettuce, carrots, and cabbage.

Do onions need a lot of space to grow?

The spacing between onions and their companion plants can vary depending on the specific requirements of each crop. As a general guideline, aim to plant onions close enough to provide mutual benefits, such as pest deterrence and soil improvement, but far enough apart to prevent overcrowding and competition for resources.

Typically, spacing onions 4-6 inches apart within rows and allowing 12-18 inches between rows works well for most companion planting arrangements.

Do onions attract pests or diseases that may harm their companion plants?

While onions themselves are relatively resistant to pests and diseases, they may attract certain pests, such as onion maggots and thrips, which can also affect nearby plants. 

However, by practicing good garden hygiene, such as removing debris and rotating crops, you can minimize the risk of pest and disease problems. Additionally, planting onions with compatible companion plants that offer natural pest deterrents can help protect both crops from common garden pests.


In conclusion, by pairing these plants together strategically, you not only create a visually appealing and diverse garden but also foster a harmonious ecosystem where each plant supports and enhances the growth of its companions. Happy gardening, and may your harvest be bountiful!