10 Companion plants for onions (and what to avoid nearby)

If you’re like me, you love having all sorts of onions on hand for cooking! They add wonderful flavor to any dish and are extremely versatile. They can be very helpful in the garden as well. People are always shocked at how useful they are for pest protection and helping your other garden plants. Because of their strong scent, they deter many pests that try to eat up your vegetables. Here are some wonderful companion plants for onions that will keep out the pesky bugs and help your onions and other vegetables grow strong.

companion plants for onions

What is companion planting?

if you have never heard of companion planting, just know that it is very beneficial to your garden. It takes some getting used to and a little research, but it’s super helpful. Plants communicate with one another and help one another, so do your research before planting vegetables closely in your garden.

Companion planting involves different plants sharing nutrients, providing shade, and even pest control for one another. Plants are constantly competing for resources, but companion planting assures that both plants reap the benefits of living together. Onions are a great place to start when doing your companion planting research.

Great companion plants for onions

Many plants benefit from growing near onions, but onions also benefit from certain plants. Here is a brief rundown of some of those plants.

1. Chamomile

Chamomile is a great plant to have in your garden to guard against fungus. It has wonderful antifungal properties that help onions who are suffering from fungal diseases. If you live in more humid areas, chamomile will greatly decrease the risk of these diseases. They also attract beneficial insects to the garden instead of pests. Chamomile is also said to improve the flavor of onions!

2. Beets

If you see flea beetles and aphids in your garden, onions can help keep these away. The scent of the onions keeps these pests away! They also help by deterring larger predators like deer and rabbits. Keep your beets safe by planting onions nearby. They make great companion plants together. Interplant them to confuse the insects!

3. Dill

Onions are one of the only edible plants that do well when planted beside dill. While other veggie plants can be negatively affected by nearby dill, onions are not. The dill even tends to bring lots of beneficial pollinators and insects to the area!

4. Carrots

Carrot rust flies are irritating garden pests that attack carrots in your garden. Planting onions between carrot plants will help keep these flies away. What’s amazing about planting these crops together is that they don’t compete for after since they tend to take water and nutrients from different levels of soil. Carrots’ roots reach deep while most onions stay just a few inches under the surface of the soil.

5. Lettuce

One benefit of planting onions and lettuce together is that they won’t compete for nutrients. Lettuce has shallow roots while onions reach a little deeper. The onions will also keep aphids and flea beetles away from your lettuce.

6. Melons

There are tons of pests that like to munch on melons and their leaves/vines. Planting onions nearby will repel the pests and let your melons grow nicely. They make great companion plants for onions.

7. Mint

Planting mint and onions near one another can result in better-tasting onions! Mint also attracts beneficial insects to themselves and the onions. Mint does spread very aggressively though, so plant these crops together in a contained area instead of a vegetable garden.

8. Brassicas

Plants in the brassica family include cabbage, broccoli, cauliflower, kale, brussels sprouts, and kohlrabi. Pests like cabbage worms, cabbage moths, cabbage loopers, and cabbage maggots will eat up brassicas. Planting onions nearby will keep these pests at bay.

9. Peppers

For anyone who plants peppers every year, you know aphids and spider mites love them. Keep those pests off your pepper plants by interplanting onions around them.

10. Strawberries

Onions also do a great job keeping pests like aphids off your strawberry plants. Since strawberries are so sweet, they attract lots of pests and insects. Onions will keep these pests away and allow them to grow beautifully.

Plants to avoid near onions in the garden

While it may seem that onions do more good than harm to other plants, there are a few that won’t benefit from being planted nearby.

  1. Alliums – Alliums and onions are too closely related and will compete for nutrients and water. They also attract the same pests. Keep these separated or planted at opposite ends of the garden.
  2. Sage – Sage can stunt the growth of onions, so keep them away. They also prefer widely different growing conditions, so one will always be struggling.
  3. Legumes and Beans – Onions can stunt the growth of beans and other legumes like peas. They require different levels of nitrogen, meaning they won’t like the same soil types. These won’t be good companion plants for onions. Don’t plant your onions near peas or beans if possible.
  4. Asparagus – Onions and asparagus prefer the same nutrients and will always be in competition with one another. Growing them together may mean stunting one or both crops.

Use this guide to assist in planting onions and other vegetables in your garden this year. Be sure to do plenty of research and read the seed packets for more specific information and what each plant likes! Figuring out the companion plants for onions is a great place to start if you want to do more companion planting. Happy gardening!

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