Hmmm, never heard that. Don't know the book at all so what is his reason or reasoning for the claim? I would hope that if he made such a claim he would explain the reason?

I have always inter-planted my onions with just about everything, at least everything that wouldn't bury and shade them out. Right now there is a long row of them next to the beets and cabbage row is planted on the other side of them. Squash and pumpkin hills will go in at the end of each row of onions when their time for planting comes. And since the onions are such a long season crop by the time they are ready to be harvested it is usually too late to plant much of anything else except some lettuce or collards or kale before frost comes.

Dave

I've got scallions so mixed up with the other salad vegetables it's almost as tho' they aren't there . . . By that I mean, individually, they take up very, very little space and I've yet to see any detriment to having them growing beside lettuce, or spinach, or radish, or even - other onions.

For the long-season sweets and storage onions, they can come out in July. I've been able to get in snow pea seed during the last week of July and harvest tendrils and pea pods in late September and into October.

Other than perhaps a surprisingly high need for nitrogen, I don't consider onions too demanding. The nitrogen can be put back into the soil for a greens crop.

digitSteve

In florida truck farms they are traditionally grown with strawberries because the moisture and fertilizer needs are compatible, and to some extent onions reduce pest pressure on the problematic strawberries.

This thread will likely become the umpteenth where we have discussed the alellopathy of onions. It exists, but the effect is very slight with seed-grown onions.

I find here in MA that not much can be grown after or near onions, if one is trying to produce sizable bulbs. Not much after because onions are long-season, and not much near because bulb onions don't tolerate competition nor shade. If one is merely producing green onions then that happens quickly of course and getting shaded out by larger crops isn't much of an issue.

Interesting that the linked thread goes right back, in a full circle, to Mr. Solomon. The route is paved with others' experiences.

Walking onions certainly can set out a robust rootzone, PNBrown. I've never tried "companion" planting of walking onions and peas or even any kind of onion and peas that I can remember. Vines have a tendency to overwhelm neighbors. It wouldn't be the lowly scallion that I would be concerned about taking over the neighborhood.

I will suggest one vegetable that can compete with walking onions - chives. They have somewhat the same environmental requirements and somewhat the same use in the kitchen . . . but, they are soooo much milder. Both will arrive about the same time of the year to be enjoyed. Chives have completely replaced the walking onions that were here when I moved to this home 14 seasons ago. Funny how that was.

Steve

Here is a link that might be useful: RE: Onions and peas together?

Well, because of timing issues/growing season limitations, I am fairly limited to cold weather crops that can be started in the greenhouse (late June/early to mid July depending upon the crop) and planted out after the onion harvest, which is generally early August here in Michigan. I suspect Denver, being roughly the same growing season as mine, would be the same.

Some of the things I plant afterwards with success are:

Raddichio; Escarole and Frisee; Various Asian greens like Chinese Cabbage, Bok Choy, Pak Choy, Etc; Florence Fennel; Collards and Kale for a fall crop (plants don't get real big, but it works); spinach; lettuce

Mind you, all of these are pretty decent sized transplants, already say 4-6 inches, and I usually start them in 25 cell trays, which is about the same soil volume as a 4" round pot.

Now, if I couldn't use transplants, but had to direct sow, in my climate, it would be even more limited -- lettuce, spinach, radishes, corn salad, etc., ie, only the fastest growing crops, things that mature in under 50 days, since growth, even on these, really slows down late in summer and into the early fall, as day length declines and night temps cool.

"I've got scallions so mixed up with the other salad vegetables it's almost as tho' they aren't there . . . By that I mean, individually, they take up very, very little space and I've yet to see any detriment to having them growing beside lettuce, or spinach, or radish, or even - other onions. "

Can you recommend a scallion seed? My son loves onions, so I planted some sets. Then he said he likes the green onions, and I told him to just snip off the greens whenever needed....and he said "the white part is the best" so I'm a loser and what to do with the onions I'm growing, lol!

But would like to get some scallions going for him. Any seed recommendations? Is it too late or can you just plant the little ones all year long?

I just harvested the last of my radishes that were planted in between the onion rows. Kept the weeds at bay and now the onions (6-8" tall) are free to grow, I just mulched them this morning to keep weed competion down. Ive only grown onions for a few years but have never had problems with putting radishes with them.

Happy Gardening
Mark

Dennis list works for me, except the fennel, which never works for me anyway. Given the long season of onions, and the fact they cast almost no shade, there is time in a season for two of the crops Dennis lists. But the second crop must be started while the onions are still there.

I realize I did not make myself clear about the "after" part. I meant during the following seasons. Steve Solomon makes the point that it's a good idea to rotate crops, but also to keep a list of what was planted where during the previous seasons so you can avoid stunting other crops. He uses onions as an example of how one crop can affect the next several years of crops.

Steve, walking onions are a year round crop for me, except when the they are frozen hard in the ground. Spring is the best time, in early summer come the tender topsets, in late summer the large basal bulbs can be used and in fall new green onions come along. I agree the flavor is strong - I don't use them raw, or at least not the Catawissa. I have a small number of a much milder white topsetter that is quite nice raw.

This year I can already note a few peas that were sowed too near where walking onion habited before being pulled out - they are not growing strong like the others. It is clear that some toxin is in the soil where the root-zone was/is. If I pull the onions in the fall and plant peas there by spring the effect isn't much or at all, so clearly the toxin dissipates fairly quickly.

Steve Solomon makes the point that it's a good idea to rotate crops, but also to keep a list of what was planted where during the previous seasons so you can avoid stunting other crops. He uses onions as an example of how one crop can affect the next several years of crops.

Sorry but that could only hold true if there is no soil amendment done during the season - much less in the off season. Why would this author assume that you'd just keep on using your soil until the tilth was destroyed and it was so nutrient deprived as to be almost sterile? Like the concept of required crop rotation, that's outdated 1930's thinking right out of Steinbeck's Grapes of Wrath and the great dust bowl!

Sure soil nutrients are used by plants, any plants, while growing. If you don't replace those used nutrients for some reason then subsequent crops could easily be stunted. But semi-annual, or at least annual, soil amendment is standard practice and easy to do.

Dave

Because of space limitation, I have already planted peppers, tomatoes
and eggplants in my onion patches. To do this had to pull up couple of onions for each.
By the time tomatoes, pepps, eggps are good size, onions will be done.
Of course, those plants need to be staked and pruned and not allowed to sprawl
I have done the same thing in the lettuce patch.