15 Best Plants to Grow with Onions for Better Growth

Onions are known for their strong aroma and natural ability to repel pests, making them a great companion for many plants.

Whether you’re looking to improve soil health, keep unwanted pests away, or increase your onion yield, companion planting can help.

In this article, we’ll explore 15 of the best companion plants for onions and how they can benefit your garden.

So without further ado, let's get into it!

1. Cruciferous Vegetables (Broccoli, Cabbage, Cauliflower, Kale, Brussels Sprouts)

Onions are excellent companions for cruciferous vegetables like broccoli, cabbage, cauliflower, kale, and Brussels sprouts.

These plants are often targeted by pests like cabbage worms and maggots, but onions help repel these insects with their strong scent.

This natural protection means that your cruciferous vegetables can grow more freely without the need for chemical pest control.

Both onions and cruciferous vegetables thrive in similar soil conditions, such as slightly acidic, well-drained soil.

By planting them together, you can make the most of your garden space while ensuring both plants grow in their preferred environment.

This combination also promotes a healthier garden overall by keeping pests at bay without competing for resources.

2. Carrots

Carrots and onions make great companions because they naturally help protect each other from pests.

Onions repel carrot flies, which are known to damage carrot plants, while carrots help prevent onion flies from harming onions.

Their root systems also don’t compete with each other—onions have shallow roots, while carrots grow deeper into the soil, allowing both plants to access different nutrients without interference.

This pairing works well in the garden because carrots can help keep the soil around onions moist, while onions, with their strong scent, deter pests that might otherwise harm both plants.

Together, they create a balanced and productive growing environment where both can thrive without competing for space or nutrients.

3. Tomatoes

Onions are a great companion for tomato plants because they help protect tomatoes from a variety of pests.

Onions repel aphids, whiteflies, and spider mites, which can damage tomato leaves and stems.

This natural pest control reduces the need for chemical pesticides, keeping your garden healthier and more sustainable.

For more tips, check out these natural ways to get rid of aphids in your garden.

Additionally, onions’ strong scent helps to keep other unwanted pests away from the tomatoes.

Tomatoes and onions also have different root systems, which means they don’t compete for nutrients.

Onions grow shallow roots, while tomatoes have deeper ones, allowing both plants to thrive without interfering with each other.

The large leaves of tomato plants also help shade the soil around onions, preventing it from drying out quickly.

This combination leads to healthier, more productive plants, making them a perfect match in the garden.

4. Lettuce

Onions and lettuce are a great pairing for small garden spaces. Lettuce grows quickly and has shallow roots, which means it won’t compete with onions for nutrients or space.

Onions, in turn, help deter pests that are attracted to lettuce, such as aphids and slugs. This natural pest protection allows lettuce to grow freely without the damage that often occurs from these common garden pests.

In addition to pest control, onions and lettuce benefit from each other’s growth habits. Lettuce grows quickly and can be harvested early, leaving room for the onions to continue growing.

This makes them an excellent option for interplanting, allowing you to maximize the space in your garden. By planting these two together, you can enjoy a healthy, productive garden with minimal pest issues.

5. Strawberries

Onions are excellent companions for strawberries because they help repel common pests that can harm strawberry plants, such as aphids and other insects.

The strong aroma of onions masks the scent of strawberries, making them less noticeable to pests. This natural pest control helps keep your strawberry plants healthy and productive without the need for harmful chemicals.

In addition to pest protection, onions also benefit strawberry plants by improving the soil. Onions help loosen the soil and release nitrogen, which is essential for plant growth.

This can lead to healthier, more flavorful strawberries. Since both onions and strawberries are low-growing plants, they don’t compete for sunlight, making them a perfect pairing in your garden.

6. Peppers (Bell Peppers, Hot Peppers)

Onions and peppers are a great combination because onions’ strong scent helps repel pests that commonly attack peppers, such as aphids and flea beetles.

This natural pest control allows your peppers to grow without being damaged by these harmful insects.

Additionally, onions can help deter larger pests like deer and rabbits, which are often attracted to pepper plants.

Peppers and onions also benefit from each other in terms of their growth habits. Hot peppers attract parasitic wasps that prey on pests harmful to onions, creating a beneficial environment for both plants.

Onions and peppers don’t compete for nutrients due to their different root growth patterns, so they can coexist without interfering with each other. This pairing leads to a more productive garden and healthier plants.

7. Beets

Onions and beets are a great pairing because onions help repel pests that are commonly attracted to beets, such as flea beetles and aphids.

The strong aroma of onions naturally keeps these insects away, reducing the need for chemical pest control. This makes onions an excellent choice to protect your beet plants while allowing them to grow undisturbed.

In addition to pest control, onions and beets share similar growing needs. Both prefer deep, loose soil, which allows their roots to spread and grow without competition.

Onions can help improve soil structure by loosening it, benefiting the beets’ root development. This combination helps ensure both plants grow strong and healthy, making the most of the space in your garden.

8. Chamomile

Chamomile is a wonderful companion for onions because it promotes their growth and enhances their flavor.

It attracts beneficial insects that help control onion pests, including aphids and onion flies. Chamomile also has natural anti-fungal properties, which can help prevent fungal diseases that might affect your onions.

The presence of chamomile in your garden can improve the overall health of your onion plants. It’s believed that chamomile’s flowers and scent help create a healthier, more balanced garden environment, encouraging onions to grow stronger.

This natural support system makes chamomile a great addition to any garden where onions are planted.

9. Dill

Dill is an excellent companion for onions, as it not only enhances the flavor of the onions but also attracts beneficial insects that help control pests.

Specifically, dill attracts predators like ladybugs and lacewings, which feed on aphids and other insects that can harm onions. This creates a natural, pest-free environment for both plants to thrive.

Dill's presence in the garden can also improve the overall growth of onions. Dill’s growth habits don’t interfere with onions, as they have different root depths.

By planting dill with onions, you can take advantage of its ability to attract helpful insects while also boosting the growth and flavor of your onions.

10. Summer Savory

Summer savory is a great companion plant for onions because it helps improve their growth and can even enhance their flavor.

This herb has natural pest-repelling properties that help keep onion flies and other harmful insects away from onions.

Summer savory's strong scent is also believed to deter pests that might otherwise target onions, offering a natural form of protection.

In addition to its pest control benefits, summer savory can contribute to a healthier garden environment.

It helps promote better onion growth by creating a balanced ecosystem and can also improve the flavor of onions. When planted together, both onions and summer savory thrive, benefiting from the companionship they share.

11. Marigolds

Marigolds are a fantastic companion for onions because they help repel pests that commonly affect onions, such as aphids, nematodes, and onion flies.

The strong scent of marigolds acts as a natural deterrent to these harmful insects, helping to keep your onion crop safe and healthy without the need for harsh chemicals.

In addition to pest control, marigolds also contribute to better soil health. They release substances into the soil that can suppress harmful nematodes, which can damage plant roots.

Planting marigolds alongside onions creates a protective barrier, improving both plant health and soil quality, while also adding vibrant color to your garden.

12. Parsley

Parsley is a great companion for onions, as it can help protect them from onion flies, which are a common pest.

The aroma of parsley helps to mask the scent of onions, making it harder for onion flies to locate their target. This natural pest control keeps onions healthier without the need for chemical treatments.

Additionally, parsley and onions grow well together because they don’t compete for space or resources.

Parsley has a shallow root system, so it won’t interfere with the onions’ growth. This pairing helps maximize the use of garden space while providing pest protection for both plants.

13. Spinach

Spinach and onions make a great pair in the garden because onions help keep pests like aphids and rabbits away from spinach.

The strong scent of onions deters these pests, ensuring that your spinach can grow undisturbed. Spinach, in turn, benefits from the space-saving nature of onions, as they both have different growth habits.

Onions and spinach don’t compete for resources. Spinach has shallow roots, so it doesn’t interfere with the onions’ deeper root system.

This makes them a perfect combination for small or crowded garden spaces. Additionally, onions’ ability to repel pests ensures that your spinach stays healthy and free from damage, resulting in a more productive garden.

14. Radishes

Radishes are a great companion for onions because they help loosen the soil, which allows the onions to grow better.

Their fast growth and ability to break up compacted soil can create a more favorable environment for onions to develop their roots and bulbs. This natural soil improvement leads to healthier onions with stronger root systems.

Radishes also work well with onions because they mature quickly, so you can harvest them before they take up too much space.

This allows onions to continue growing without being crowded. Additionally, radishes act as a decoy for some pests that are attracted to onions, drawing them away and helping to protect your onion plants.

15. Garlic

Garlic is a natural companion for onions due to its ability to repel pests like aphids and onion flies.

Even though both garlic and onions belong to the same plant family, they work well together by providing mutual protection.

Garlic’s strong scent helps deter pests that can harm onions, reducing the need for chemical pest control.

In addition to pest control, garlic shares similar growing needs with onions, making them easy to plant together.

Both plants prefer well-drained soil with adequate sunlight. This makes garlic and onions a perfect duo for gardeners looking to maximize their space and protect their crops while maintaining a healthy garden.

Pair onions with these companion plants to boost growth, protect against pests, and create a healthier garden!

Companion planting with onions offers numerous benefits, from protecting your crops against pests to improving soil health and maximizing space.

By pairing onions with the right plants, such as carrots, tomatoes, or marigolds, you create a healthier, more productive garden that works in harmony.

Whether you're looking to repel harmful insects, enhance flavor, or promote growth, companion plants can support your onions in many ways.

By using these natural partnerships, you can reduce the need for chemicals, encourage biodiversity, and enjoy a thriving, sustainable garden.

Frequently Asked Questions (FAQs)

1. Can I plant all of these companion plants together with onions?

While many of these plants can be grown together, it’s important to consider their specific needs. Some plants, like carrots and onions, grow well side by side without issue, while others might need more space or specific conditions. It's best to plan your garden layout to ensure that each plant has room to thrive and isn’t competing for resources.

2. How do companion plants help with onion pests?

Companion plants like marigolds, garlic, and dill help repel pests such as aphids, onion flies, and carrot flies. The strong scents or natural chemicals these plants release act as a deterrent, keeping harmful insects away from your onions and other crops. This reduces the need for pesticides and supports a healthier, more natural garden.

3. Are there any companion plants that should not be planted with onions?

Yes, there are a few plants that don’t pair well with onions. For example, peas and beans can struggle when planted near onions due to different soil nutrient needs. It's important to research plant compatibility to avoid negative interactions that could stunt growth or attract pests.

4. Can I use these companion plants in a container garden with onions?

Yes, many of these companion plants can be grown in containers alongside onions. Just make sure each plant has enough space to grow and that the container is large enough to accommodate both the onions and their companions. Also, ensure proper drainage and sunlight for all the plants involved.

5. How does companion planting affect onion yield?

Companion planting can significantly improve onion yield by protecting the plants from pests, enhancing soil quality, and maximizing space. Plants like radishes, beets, and chamomile help create an environment that allows onions to grow stronger and healthier, leading to better overall production.