The 12 best companion plants for onions

companion plsnts for onions

Onions come in various shapes and sizes, from large bulb onions to red onions, to scallions. They are stapled food products because they add flavor to any dish. So, this makes them a target for gardeners to plant. 

If you don’t want a garden full of onions, you might want to introduce another crop in the same garden. Try finding a crop beneficial to onions. By planting plants that benefit from each other, the end product is a healthy plant free of diseases. This is called companion planting.

In most cases, people use onions as companions for most plants, but in some cases, you need companion plants for onions. So, it’s better to know which plants can accompany an onion and which the onion cannot withstand. 

So, let’s go gardening to help you know the best companion plants for onions and the worst companion plants for onions.  

What is Companion Planting?

Companion planting is a practice that involves planting a variety of plants in the same garden for beneficial purposes. These plants are chosen carefully while considering how they will benefit the other plant. For instance, rather than planting an entire row of onions, you plant onions and carrots in that row. 

When you think about it, everything has a reason for doing it. This practice benefits the other plant by keeping pests away, boosting production, or attracting pollinators. 

Why Do Companion Planting?

This planting practice is the easiest and best way to encourage other plants to grow into healthy plants. But what is the importance of companion planting with onions?

  • You get healthy plants free from diseases
  • They have a scent that can repel insects

Other than this, companion planting offers a variety of benefits, including enhancing growth, improving flavor, and attracting pollinators. 

Best Companion Plants for Onions

You must choose the best plants that suit your garden. We are providing you with various plants and how they benefit onions. 


companion plants for onions

The combination of onion and carrots is a classic combination used b many farmers. In this combination, they have a symbiotic relationship whereby the scent of carrots deters onion fly while the scent of onions deters carrot root fly. 

Another advantage of these two plants is that they don’t compete for water and nutrients because they take them from different levels of the soil. 


Brassicas is a family name for crops such as cabbage, lettuce, and broccoli. When you plant these vegetables with onions, they will benefit significantly from onions. Because it has a strong scent, they tend to cover up the cabbage scent, confusing pests such as rabbits. 

Another benefit is that onions can provide good resistance to insects such as cabbage worms, weevils, and cabbage looper. 


Beets are an excellent companion to onions. Onions protect them from insects and pests such as aphids, flea beetles, and rabbits. And at the same time, beets protect onions from thrips. 


The chamomile flower is known for its antibacterial and antifungal properties. The antifungal properties ensure that fungal diseases never attack onions. But, in this case, you can use them as companions to add flavor to onions. For this to work, you need to plant them close to each other. 

Since chamomile has a sweet aroma, they make good companions for attracting pollinators and scaring away pests. 

Tomatoes, Peppers, and Eggplant.

In this companionship, onions help these plants control pests that attack them. Other than onions, you can use alliums as companions. The scent from these plants is used to scare away pests that like attacking them. 

Also, growing onions near these plants, especially tomatoes, improves their flavor.  


A companionship between melons and onions benefits the melons, as the onions help keep pests away. 


Potatoes are among the best plants to intercrop with onions because they can benefit each other with pest control. Pests are the main problem that kills plants, so if you find plants such as these that control pests, then it’s best if they are planted together. 


Strawberries are sweet plants but are small and very vulnerable to pests. Onions, on the other hand, have a strong smell that can deter pests. Onion scent is essential because it covers the plant’s scent, confusing the pests using their scent. 

Summer Savory

Summer savory is a herb plant that can aid onions as a companion plant. It’s good because it helps onion improve its growth and flavor. 


Mint is another companion plant beneficial to onions. If you plant mint next to onions, it keeps onion flies. The only disadvantage is that it spreads fast and can cover the whole garden. Prune it to ensure it doesn’t spread. 

Pigweed (Amaranth)

Pigweed is a flower that can be beneficial when planted next to onions. It is capable of improving soil quality by drawing nutrients. This way, onions will have nutrients to help them grow into healthy and strong plants. 


As an ornamental plant, it tends to suffer from insects and pests. Planting a companion plant such as onions can help keep away all those pests such as aphids and black-fly.  

Worst Companion Plants for Onions

As you have read above, there are good and bad companion plants for any plant in the garden. That applies to onions. Here are the worst companion plants for onion. 


Legumes include plants such as beans and peas. It’s not advisable to plant legumes together with onions because they kill bacteria that help legumes grow. Once the bacteria die, the legumes will have stunted growth. 

On the other hand, Legumes are good for onions, but you must plant onions after removing legumes. Since legumes fix nitrogen in the soil, the nitrogen can help onions grow because they are heavy nitrogen feeders. 


The flavor of asparagus is important to the herb. Onions affect asparagus, which leads to their student growth and flavor. Thus, ensure you don’t mix it with onions on the same bed. 


Sage and onion have different requirements for them to grow. In most cases, sage causes stunted growth of onions. Thus, if planted together, they might fight for food, resulting in one of them dying. 


Companion planting not only helps plants, but also improves the soil quality in a garden. This way, you don’t plant a crop that will affect another. But, you have to make sure you choose crops that are suitable for each other. That’s why we are helping you find the best companion plants for onions. This guide does not have all the possible companion plants, but it can help you narrow down the gap from the long list of plants available. 

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