I did that last year and it worked ok for me. The onions didn't actually take up that much room, but the broccoli got really big, so if you want to do it, make sure there's lots of space for the broccoli. It also tends to spread out leaves and block the light from nearby plants. I also put broccoli in my sq foot garden (1 plant per square) and I think it was still too big. The neighboring squares were shaded from the sun and the spinach grew very poorly until I took the broccoli out.

I grow my main crop of onions in their own bed so I can spoil them, but I often stick sets in the ground between broccoli, cabbage, etc. But I think my most successful interplant ever was with Salad Bowl lettuce about 8 inches out from the base of the broccoli plant. Allowing a wide, heat-resistant leaf lettuce to fill the space between brocs cut down on weeding and both crops prospered.

When you are logged in go to the bottom of this page and click on "Member Pages" in the green bar. Then on that page scroll down to and click on "Edit Your Personal Information, Page, and Preferences". Make your changes and save.

Dave

Thanks much. I didn't think about the fact that of course the onions need the sunshine on them, and the broc will shade them. So I'll just keep to growing lettuces in the onion bed. A brag: the garlic crop I harvested last year - about 70 bulbs - were all grown from the cloves from the year before. Looks like I fixed the preferences page - thank you.
I would like to show a pic of our root cellar with all the lovely garlic braids hanging there (braided by me...). How might I do that?
Thanks again.

I put broccoli about 12 inches apart, then filled in with garlic & onions(I have been told not to plant onions & garlic together, too easy for the bad bugs to find both).
I still had some room so I seeded turnips.
We had ONE night at 19 degree F & it killed my broccoli.
But the onions, garlic are doing fine in the turnip patch.

Jolj: the shading of the garlic and onions by the groc wasn't a problem? My garlic bed is 4X8, and there's plenty of room for broc, but my concern is the shading of the garlic. (And I can't see why onions and garlic couldn't be planted together - the bad bugs are terrified of both garlic and onions) What variety of broc did you plant?
And do you happen to know how to post a picture?

Broccoli and onions is a bad idea, because the broccoli are so tall and shade the onions, which requires full sun. Onions and spinach, onion and lettuce, onion and radish, onion and beets all work, with my favorite being the lettuce because it is a good living mulch and does not mind a bit of shade.