In this article: Learn which crops are the best onion companion plants to increase your garden harvest, reduce pests, and improve flavor.
Companion planting with your onions can help your plants grow better, taste better, and have less problems with pests. So how does companion planting work? What can you grow with onions and what should be kept far away?
First off, onions are a member of the allium family. Other alliums include garlic, leeks, shallots, and chives.
Below you will find a list of onion companion plants that you can grow alongside your onions to prevent pests and disease, or just help your garden grow and taste better. Plus a list of what you should keep separate from your onions.
Companion planting does take time to plan each year, so check out my Yearly Garden Planner to help you plan your garden beds before you plant so you can take advantage of companion planting!
Onion Companion Plants For a Better Harvest
Companion planting has a lot of benefits including improved flavor and better growth. It’s important to plant crops that don’t compete for nutrients and also complement each other. Below is a list of plants to grow with your onions to help you grow your best garden ever!
Lettuce: Lettuce and onions make great companions. They do not compete for nutrients in the soil and their roots don’t take up the same soil level.
Onions can also help deter insects from eating your lettuce.
Chamomile: Chamomile can help improve the flavor and growth of your onions. Other herbs such as summer savory and dill can have the same effect.
Strawberries: Onions may not benefit from strawberries, but growing onions alongside your strawberries can improve growth and health in your berries.
The strong smell of onions can also confuse pests and keep them from munching on your berries.
Beets: Beet and onion roots draw from different soil levels and won’t compete for nutrients.
Onions may also protect your beets from some fungal infections.
Tomatoes: Onions can do a lot for your tomato crop including improving the flavor of the fruits.
Onions can also help deter pests like aphids in your tomatoes.
Peppers: Peppers are nightshades like tomatoes and reap the same benefits as tomatoes. Flavor enhancement is more likely to be seen in hot peppers.
Onion Companion Plants for Pest Control
Pests can be a big problem in organic gardens, or any garden, but luckily one of the main benefits of companion planting is to naturally deter and eliminate many of these pests. Below are some of the best onion companion plants to help control some of the main garden pests.
Cabbage: Onions- and others in the onion family- are good companions for cabbage.
Onions can help repel lots of pests that can feed on your cabbage such as cabbage loopers, cabbage worms, aphids, and Japanese beetles.
Broccoli: Broccoli is in the same family as cabbage so onions will repel the shared pests. This goes for not just broccoli, but Brussels sprouts, kale, collards, and other brassicas.
Carrots: Onions and carrots offer each other a symbiotic relationship. Onions help deter carrot flies and carrots can help protect onions from onion flies.
Parsley: Parsley is related to carrots so onions offer it the same protection from carrot flies.
Celery: Celery is another crop in the carrot family. Companion planting onions with your celery will help deter pests that might feed on your celery plants.
What to Avoid Planting With Onions
Onions aren’t too picky, but there are a couple of plants that should not be planted near onions due to either flavor contamination or chemical interactions.
Beans: Onions should not be planted with any type of beans. Onions may stunt the growth of beans. This goes for all members of the allium family.
Peas: Peas are legumes like beans. Keep onions away from all legumes including peas.
Sage: Many farmers swear that sage is harmful to onions. It can stunt the growth of the roots.
Asparagus: Onions can stunt the growth of your asparagus.
Onions can also contaminate the flavor of your asparagus.
Turnips: Onions can negatively affect the root growth and flavor of turnips. If you are growing turnips for the greens, onions can be okay.
Other Alliums: Growing other alliums closely together can cause more trouble with onion maggots. Spreading them through the garden will control the pest.
Once you have harvested your onions, check out some of the following articles to learn how to store, use, and preserve your harvest!
And that’s it for companion planting with onions. Take this information into account while planning your garden in the spring and you will see the benefits of companion planting!
Other Companion Planting Guides:
Don’t forget to pick up a copy of my companion planting chart below!
© 2019, Sarah R Toney. All rights reserved.