Using Onions for Sulfur to Increase Acidity in Soil?

Ok I'm a newbie so go easy on me..I want to increase the acidity in a strip of soil along the side of my yard so that I can plant some things there that like it about 1-1.5pH lower than it currently is (bring down to 5.5-6.5 range). I'm thinking to plant those more acid-loving plants sometime next year. I've done a bit of reading about adding elemental sulfur to the soil to lower pH over longer periods.

My question is about onions, and to a lesser extent maybe garlic. They contain sulfur compounds so can those be used the same way to lesser effect? When I use an onion for cooking, I usually only use half and I haven't been composting the remainder (I do compost other things).

If they would work, how should I go about this? Should I just dig little holes in that soil strip and drop in my extra raw onion bits as I have them leftover? Or should I try to compost them separately first? If so, how should I do that because I've read that onions and garlic can inhibit the more common compost organisms and be discouraging to worms so would an onion-heavy compost or "soil amendment" work or be more damaging? I don't want to just add them to the rest of my compost because now that I'm thinking about it, I want to see if there's a way to basically super-charge their usage to increase sulfur and therefore acidity over a small area vs. having it spread across the entire compost pile and therefore minimal effect if at all.

I'm having a hard time figuring out whether this might work or at least how to experiment more effectively. Maybe the quantities of sulfur within these veggies are comparatively so low that they wouldn't really have an effect at all? I don't need them to fully lower the pH on their own but was hoping there was a way they could either assist or slow the eventual deterioration of other methods I might use.

The plants that are commonly thought to love acid soils, usually  just need a more fungal dominant soil (blueberries for instance).  Rotted tree bark, rotten leaves will do that.  

Colleen,
 If you can give the Permies people more information about what is growing on that soil now and what plants you wish to grow, or maybe also a photo of that stretch of ground, we might be able to help more.  

Faye Streiff wrote:The plants that are commonly thought to love acid soils, usually  just need a more fungal dominant soil (blueberries for instance).  Rotted tree bark, rotten leaves will do that.  

Interesting thought. Does that apply "across the board?' It seems to me that the pH of the base mineral soil has a great deal of influence.

Colleen Barclay wrote:Ok I'm a newbie so go easy on me..I want to increase the acidity in a strip of soil along the side of my yard so that I can plant some things there that like it about 1-1.5pH lower than it currently is (bring down to 5.5-6.5 range). I'm thinking to plant those more acid-loving plants sometime next year. I've done a bit of reading about adding elemental sulfur to the soil to lower pH over longer periods.

My question is about onions, and to a lesser extent maybe garlic. They contain sulfur compounds so can those be used the same way to lesser effect? When I use an onion for cooking, I usually only use half and I haven't been composting the remainder (I do compost other things).

Hey Colleen. It's pretty tough to drop soil pH that low in a permanent way. Elemental sulfur feeds certain soil bacteria that excrete sulfuric acid. The effect doesn't last. In my area, it's mostly used to suppress soil denizens that produce "scab" on root vegetables. Sometimes it works, but the rain/drought cycle is the biggest factor/wild card.

Sorry to say, but i rather doubt half an onion will do much of anything. Setting up a micro-trade system with your neighbours, on the other hand, may have all sort of beneficial effects. My 2c.

Hi Colleen,

Welcome to Permies.  You never have to worry about the other members going easy on you.  We take our “Be Nice”policy seriously.

Welcome to the forum!

I feel that onions get their sulfur from the soil rather than giving the soil sulfur.

I believe that building healthy soil will solve most problems.

Dr. Bryant Redhawk has done much research into this idea.

https://permies.com/wiki/redhawk-soil

Especially these:

https://permies.com/t/76498/biology-soil

https://permies.com/t/123928/Growing-Plants-builds-soil-health

https://permies.com/t/124772/Nature-Works-Moving

Also here is a youtube that might be of interest:

Dr Ingham explained the damage of sulfur to the soil and the better way to get the soil pH right

You could ask your coffee shop to save their grinds to incorporate it into the ground and slowly change the ph (citrus plants flower right after grinds).
A fast method is to also brew coffee and add it to your soil or compost. You could also use the extra tomato pulp from theaters and stand up joints.
a small amount of Epsom salts (this will give you sulfate ions that will form acid when water is added) could do it, I haven't done the test but I think you wouldnt have to added it regularly unless you planted mustard and arugula.
I could help you get the proportions of Epsom salts if you have a pH meter

Wow this is awesome, thanks so much everyone for your responses.

Thank you in particular Anne Miller for that video of Dr Ingram. What she said along with what Faye commented here makes more sense to me and seems to line up better with other things I've been reading about. My hunch is the lower pH where "acid loving" plants thrive is a byproduct of other conditions in the soil that are also helping them such as higher water throughput, frequently replenished decomposing organic matter, and microorganisms that are producing acid.

Regarding some of the other things that were brought up:

Nothing much is currently growing in the strip of soil I originally asked about and I don't know a whole lot else about it yet either. I was a bit vague about it and what I was trying to grow on purpose even though I knew the advice would be less specific because I'm trying to consider different setups right now (more of a "what if" that I could apply to different possibilities).

I'm in Colorado and there are lots of dry periods and our soil and tap water is alkaline so I don't expect that anything I add in an attempt to lower pH would be permanent because over time repeated applications of tap water and/or those natural conditions are going to return. What I am hoping to be able to do is to use things that are already in my waste stream to slowly and repeatedly apply to lower pH, with the assumption that if it works it will only keep working as long as I keep doing that.

I am actually attempting to grow blueberries but that was not the scenario I was originally asking about. The blueberries are in peat moss in isolated containers from the rest of the soil. I was originally planning on just following the guidance from the Colorado State University extension which essentially involves regular applications of acid to counteract the slow pH increase caused by watering. However, after absorbing the information in this thread further, I'm going to abandon the idea I originally asked about (for now) and see if I can apply some of these ideas to my blueberries instead.

My plan now is to take any waste products I have that are naturally high in acid or sulphur - for example, onions, tomato, raw fish, and bury small amounts 3-6 inches deep (poke a hole and drop in) about once per week to each plant. Luckily I have two of each of different varieties to test on so if I track what I add and test pH regularly, I will be able to report back in a few months to a year whether those plants are did better/worse or maintained soil pH any differently than the ones which just got standard compost and acid treatments.