Beans and garlic; how close is too close?

I am planting a bunch of types of dry bush beans.

I have overly wide paths between my garlic beds, due to tractor geometry. Plenty of room for a row of beans down each path..

But, lots of sources say that garlic will stunt beans...

How close is too close?

What is the mechanism responsible for the stunting?


Has anyone experienced stunted beans that they would blame on garlic, or grown them close with no issue?

D Nikolls wrote:But, lots of sources say that garlic will stunt beans...

How close is too close?

What is the mechanism responsible for the stunting?


Has anyone experienced stunted beans that they would blame on garlic, or grown them close with no issue?

It won't answer the primary question, but I have learned that garlic puts out sulfur through its roots. I had a sulfur deficiency in my natural (non-chemical) hydroponics last year and this year I tested putting a clove of garlic in several of my buckets. The plants with the garlic had distinct signs of sulfur toxicity (stunting, burning leaf edges, lower uptake of nitrogen). The problem was immediate, once the garlic started putting down roots. One of these was a bean. Since I took the garlic out it has returned to regular growth. This was in the same net pot, so within inches. I'm guessing that at least part of the problem with bean stunting is sulfur. The bean, of course, wasn't affected by the nitrogen issue, but it was severely stunted and had the burned leaf edges of sulfur toxicity.

Lauren Ritz wrote:
It won't answer the primary question, but I have learned that garlic puts out sulfur through its roots. I had a sulfur deficiency in my natural (non-chemical) hydroponics last year and this year I tested putting a clove of garlic in several of my buckets. The plants with the garlic had distinct signs of sulfur toxicity (stunting, burning leaf edges, lower uptake of nitrogen). The problem was immediate, once the garlic started putting down roots. One of these was a bean. Since I took the garlic out it has returned to regular growth. This was in the same net pot, so within inches. I'm guessing that at least part of the problem with bean stunting is sulfur. The bean, of course, wasn't affected by the nitrogen issue, but it was severely stunted and had the burned leaf edges of sulfur toxicity.

This is interesting! Would this also mean that it might not be a good idea to plant beans where garlic was (garlic came out in June so beans could go right in after)? Or would the excess sulfur disappear as soon as the garlic does?

Sanna Heijnis wrote:

Lauren Ritz wrote:
It won't answer the primary question, but I have learned that garlic puts out sulfur through its roots. I had a sulfur deficiency in my natural (non-chemical) hydroponics last year and this year I tested putting a clove of garlic in several of my buckets. The plants with the garlic had distinct signs of sulfur toxicity (stunting, burning leaf edges, lower uptake of nitrogen). The problem was immediate, once the garlic started putting down roots. One of these was a bean. Since I took the garlic out it has returned to regular growth. This was in the same net pot, so within inches. I'm guessing that at least part of the problem with bean stunting is sulfur. The bean, of course, wasn't affected by the nitrogen issue, but it was severely stunted and had the burned leaf edges of sulfur toxicity.

This is interesting! Would this also mean that it might not be a good idea to plant beans where garlic was (garlic came out in June so beans could go right in after)? Or would the excess sulfur disappear as soon as the garlic does?

I don't know whether it would disappear. I suppose it would eventually. Since beans are a nitrogen fixer, I shouldn't think that the nitrogen issue would be a problem. The pots with the beans weren't just being watered with a sulfur additive, but actually had a growing garlic bulb in with the main plant. I suspect the sulfur toxicity was because of proximity more than the presence of the garlic bulb, but that would be something else to test.

Interesting. I never heard this before. But it might be an explanation why the green beans I planted did not succeed (only one of them has grown out to be a plant, with a few beans): there was garlic in the same bed. Very close in distance and partly overlapping in time.

Sanna Heijnis wrote:

Lauren Ritz wrote:
[...] garlic puts out sulfur through its roots. [...]

This is interesting! Would this also mean that it might not be a good idea to plant beans where garlic was (garlic came out in June so beans could go right in after)? Or would the excess sulfur disappear as soon as the garlic does?

Can't answer about beans, and not sure sulfur is the only thing going on there. What I can attest is that garlic's unfriendly effect definitely can last at least six months, apparently longer for some 'followers'.

Source: Accidental experiment when I put garlic into a spare space in my main garden one fall, and tried easily a half-dozen things in that space mid-late summer after harvest. Dill died, cucumbers died, squash died, and I think I tried some flowers also. It's in kind of a bridge place between two sections, and this season I've lost a tomato there and a couple of peanuts. So, not an experiment I'll try again any time soon.

Lauren Ritz wrote:I have learned that garlic puts out sulfur through its roots.

I wonder where it gets the sulfur.

ETA: I went and read up. The deal is, soil is rich in sulfate -- which all(?) plants need, including beans. But alliums and especially garlic produce sulfur-based organic molecules (allicin, ajoene, diallyl disulfide, methyl allyl sulfides, &c.) that can harm certain microbes and plants, and legumes are especially vulnerable. So, neat!

Well, that explains why, when I first started my little food forest with young fruit trees surrounded by garlic or onion bulbs and different types of legumes planted to vine up the wire cages around the saplings, the legumes never took off.  I had assumed some critter or other ate them as they emerged, but the close proximity to the garlic and onion may actually have been the issue.  🤦‍♀️

Yeah that tracks with what happened in my food forest too. Planted beans to fix nitrogen around young fruit trees but had garlic and onions nearby and nothing took. Took me embarrassingly long to put two and two together.