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Yes, you can plant broccoli with onions, and it’s actually a pairing that works well in the garden.
These two crops have different root depths and nutrient needs, so they don’t compete aggressively with each other.
Many gardeners plant broccoli with onions because the onions can help deter common pests that bother broccoli.
In this post, we’ll look at why you can plant broccoli with onions, how to space them, and what to watch out for so both crops thrive.
Let’s dig in.
Why You Can Plant Broccoli With Onions
You can plant broccoli with onions for several solid reasons, and here’s why they make good garden companions:
1. They Occupy Different Root Zones
Broccoli has a deeper, more extensive root system, while onions root fairly shallow.
Because of this, when you plant broccoli with onions, they draw nutrients and water from different levels of the soil.
That means less direct competition and more efficient use of your garden bed.
2. Onions Help Repel Pests
One of the biggest reasons to plant broccoli with onions is pest control.
Onions give off a strong sulfur scent that many broccoli pests, like cabbage worms and aphids, find unpleasant.
When you plant broccoli with onions, the onions act as a natural deterrent, reducing the need for sprays.
3. They Have Compatible Growing Conditions
Broccoli and onions both enjoy full sun and well-drained soil.
They also both prefer cooler weather, which makes them natural partners in spring and fall gardens.
Since their temperature and moisture needs overlap, it’s easy to plant broccoli with onions in the same bed.
4. They Don’t Share Major Diseases
Broccoli belongs to the brassica family, while onions are alliums.
Because they come from unrelated plant families, they rarely share the same soil-borne diseases.
That’s another reason you can plant broccoli with onions without worrying about passing problems back and forth.
How to Plant Broccoli With Onions
If you want to plant broccoli with onions the right way, a little planning goes a long way.
Here’s how to set up your bed:
1. Give Broccoli the Space It Needs
Broccoli grows into a large plant and needs about 18 to 24 inches between each one.
When you plant broccoli with onions, place the onions in the gaps between and around the broccoli.
This way, the onions fill empty space without crowding your broccoli.
2. Plant Onions Around the Edges
Onions work great planted along the border of a broccoli patch.
When you plant broccoli with onions along the edges, the onions create a scented barrier that pests dislike.
Keep onion sets about 4 to 6 inches apart from each other for healthy bulb development.
3. Time Your Planting Together
Both crops do well when started in cooler weather.
You can plant broccoli with onions at roughly the same time in early spring or late summer.
Just make sure the soil is workable and not waterlogged before you start.
4. Water and Feed Evenly
Both crops need consistent moisture, but neither likes soggy soil.
When you plant broccoli with onions, water deeply once or twice a week rather than lightly every day.
Feed with a balanced fertilizer so both the broccoli heads and onion bulbs get what they need.
Things to Watch Out For
While it’s smart to plant broccoli with onions, a few issues are worth keeping an eye on.
1. Avoid Overcrowding
The biggest mistake when you plant broccoli with onions is planting too tight.
Broccoli needs airflow around its leaves to prevent mildew and disease.
If onions crowd the broccoli stems, thin them out so both plants can breathe.
2. Watch for Onion Thrips
Onions can attract thrips, which occasionally spread to nearby plants.
Check onion leaves regularly when you plant broccoli with onions so you can catch any infestation early.
3. Don’t Plant Them After Related Crops
Avoid planting either crop where brassicas or alliums grew last season.
Rotating your beds keeps soil healthy whenever you plant broccoli with onions in the future.
So, Can You Plant Broccoli With Onions?
You can plant broccoli with onions, and it’s a smart companion pairing for most gardens.
They use different root zones, share similar growing conditions, and the onions even help keep broccoli pests away.
Just give each plant enough space, keep the soil evenly moist, and watch for the few issues we covered.
Plant broccoli with onions this season and enjoy two harvests from one bed.