What companion plants should be avoided near onions?
Written by
Olivia Mitchell
Reviewed by
Prof. Martin Thorne, Ph.D.Smart companion planting makes your onions healthier and more productive! Stay away from plants that try to outcompete them or release harmful chemicals of their own, like beans and peas. They stunt the onions via root competition. I learned that important lesson the hard way when I picked so many half-size bulbs off my bean-onion row. Your choices when planting them will determine whether you have too many and need to give them away or not have enough for a harvest.
Keep your sage and asparagus away from onions. Sage shares oils that impede root growth, as does asparagus, with common pests such as the thrips that spread from crop to crop. In my garden, I keep them at least 10 feet away from onions. Your pest control is always improved with proper spacing.
Welcome to carrot companions. Carrots deter onion flies, and onions keep carrot rust flies at bay. I like to plant them in alternating rows, and their mutual protection has significantly reduced my pest issues. Your chemical-free garden will take just as kindly to this pairing.
Pest Control Pairings
- Lettuce: living mulch cooling soil
- Marigolds: deter nematodes and beetles
- Dill: attracts beneficial wasps
Flavor Enhancers
- Chamomile: boosts bulb sweetness
- Beets: improves mineral uptake
- Parsley: increases essential oils
Space Optimizers
- Spinach: shallow roots avoid competition
- Radishes: quick harvest before bulb expansion
- Cabbage: vertical growth maximizes light
Three-year rotation cycles with non-alliums. Following onions, legumes, to restore nitrogen. Don't plant onions in the same bed twice. I draw a map of my garden once each year to help break up the cycles to prevent diseases. Your bed will become stronger for it.
You can maximize your chamomile benefits by planting around your bulb zones. Chamomile has roots that share nutrients that help intensify the complexity of onion flavor molecules. I brew the spent flowers into tea for watering my onions. The difference in your culinary results is notable when using these.
Keep track of all plant relationships throughout the gardening season. Yellowing onion plant foliage may be caused by an unhealthy amount of competition from nearby bean plant(s). Stunted growth means that whatever plant may be growing near your sage will need to be spaced further apart. I routinely take photos every week during my gardening season to track changes in my plants throughout the year. Observations you make will ultimately help you develop or improve your future planting plans.
Read the full article: How to Grow Onions Successfully at Home
