Acidifying Soil Without Peat Moss

I just got back from visiting my next-door neighbor the first time, and picking blueberries with her in her beautiful blueberry patch. I am so impressed with how healthy and productive her bushes are, and definitely want to plant some of my own, both for us to eat, and to sell.

However, she adds quite a lot of peat moss each year to keep the soil acidic. Like a few inches on top of the soil each year. Plus the original plants were planted in a hole filled in with peat moss. I do not want to do this, for obvious reasons.

Our soil pH is 5.98, and, according to the internet, blueberries prefer a range of 4.3 to 5.5. Are too far out of the range for them to do well? And is there a good, permie way to lower the pH enough to be successful? Yes, I know the correct permie thing would be to grow something that does well here all on its own (and I am doing that in most cases). But oh my gosh, these blueberries are just so fantastic, and I really want some of my own! I know they would sell like crazy at a market too.

The commonly held wisdom seems to be that coffee grounds and pine needles both acidify the soil. But then I have also read on here that once those things have composted down, they do not affect the pH one way or another. Maybe I am misremembering that, though. The internet in general presents a wide range of conflicting info on coffee grounds. I think I could pretty easily get coffee grounds from business in town, if that would help. My thought is it probably would not do enough.

I have plenty of time to think about this, since autumn is the time for planting such things here.  

Lila, if you don't already make compost now is a good time to start.

Yes, coffee grounds will work.

Once you get the compost going, you can use compost tea.

Also, wood chips will help.

These threads will offer helpful information to you or others:

https://permies.com/t/126240/heck-Humus

https://permies.com/t/63914/Soil

There aren't a lot of ways to lower soil pH (make soil more acidic).

One method is the application of elemental sulfur. My understanding is that it doesn't acidify directly, but is metabolized by bacteria that excrete acidic compounds. It has to be reapplied periodically.

Provided that there is a health and diverse soil microbiome, the plant will create its own ideal Ph in and around its zoot zone.

Developing a suitable fungal dominated soil structure, and inoculating with a wide spectrum of organisms harvested from healthy soil is a good starting point.

I started out with very alkaline ground, and used powdered sulfur at the recommended rate.  It dropped my soil pH from 8.5 to 6.5, and it has stayed that low for years now.

I suppose you can buy one extra box and keep that as a reserve if you retest years from now and you've found it to be going back up.

I use elemental sulfur in all my beds. ( not sulfate sulfur) My ph is just over 8. In the beginning I got a lot of blossom end rot. So I used enough to get it down to 7.  It takes a couple of months for the bacteria or whatever to start to break it down. But it seems to last 4-5 years. I just replenished all my beds late this winter. Little 4 pound bags are expensive but lots of hardware stores carry it in 20 pound bags for about $16.00.  Makes my garlic really happy to.
https://permies.com/t/175278/local-source-elemental-sulfur-Pennsylvania

According to this site blueberries will grow on soil between 3.5 and 6.5, so there's a good chance they should grow OK for you, without changing the soil pH.
There is a bit more to it of course. They do like moist but not waterlogged soil, so making sure the soil has plenty of organic matter will really help. My soil is very acidic, but compacted and silty. My first blueberries struggled and mostly died. It wasn't till I prepared them a raised bed (like a mini hugel) that they seem to be doing better, and I'm hopeful that if I beat the mice and birds I may get some fruit this year!

A method I've used from Feedipedia is to blend up citrus rinds from after jucing them or eating them, use that "pomace". It works great! And I needed a use for the leftover citrus rinds, as we eat a fair amount of lemons and limes weekly.

Nick Kitchener wrote:Provided that there is a health and diverse soil microbiome, the plant will create its own ideal Ph in and around its zoot zone.

Developing a suitable fungal dominated soil structure, and inoculating with a wide spectrum of organisms harvested from healthy soil is a good starting point.

I think there is much truth in that, and it's a goal that lets us thumb our noses at global supply chains. Good.

Still, it's worth considering that the general pH trend in soil is related to the bedrock of a region. For example, the Canadian Shield (granite, naturally acidic) is quite different from the Western Sedimentary Basin (limestone, naturally basic). As a result, techniques for pH adjustment vary.

Kim Goodwin wrote:A method I've used from Feedipedia is to blend up citrus rinds from after jucing them or eating them, use that "pomace". It works great! And I needed a use for the leftover citrus rinds, as we eat a fair amount of lemons and limes weekly.

OMG, this is why I read Permies.  I have bounced repeatedly off the problem of acidifying soil in a sustainable way -- for blueberries and such -- without having to buy industrial/mined inputs from far away, or really, spend money on any products.  I am a bit too far north to grow citrus freely outdoors, and we don't buy that much of it, but...

I can and do grow hardy orange trees, poncirus trifoliata, and they thrive here.  The culinary uses for those fruit are, well, "marginal" is about the nicest word, although I do hope to make some unique local tonics/bitters when my trees really start fruiting.  But if I can use the fruit as an acidifying soil/compost amendment, that alone will be a good reason for all my lovely poncirus trees!

Dan Boone wrote:

OMG, this is why I read Permies.  I have bounced repeatedly off the problem of acidifying soil in a sustainable way -- for blueberries and such -- without having to buy industrial/mined inputs from far away, or really, spend money on any products.  I am a bit too far north to grow citrus freely outdoors, and we don't buy that much of it, but...

I can and do grow hardy orange trees, poncirus trifoliata, and they thrive here.  The culinary uses for those fruit are, well, "marginal" is about the nicest word, although I do hope to make some unique local tonics/bitters when my trees really start fruiting.  But if I can use the fruit as an acidifying soil/compost amendment, that alone will be a good reason for all my lovely poncirus trees!

Right there with you!  I find the most amazing ideas here.  When I've combed through the internet and can't find an answer that makes sense to me, I reach out here and the most surprising ideas get presented oftentimes.

I feel like here at Permies, I'm surrounded by people who not only think outside of the box, they've dissolved the walls of the box.

I was trying to find the link, but Feedapedia is like an encyclopedia and though I've read about 1/3 of the info there now, I don't know where everything is!   And maybe I found it somewhere else... I recall a photo that looked like a Moroccan farmer?  Anyways, there is somewhere in the world that using citrus pomace as a soil amendment is common.

So I'll tell you how I've been acidifying things here in the desert, where acid is a precious resource.  Might give you more ideas.

Using citrus pomace (citrus rinds blended with some water, I mean). I'm in the desert and chlorosis is a big problem here. Iron (and also calcium) can get locked up in the soil and be unavailable to plants.  When this happens with iron, the plant's leaves turn yellow with the only green left in the veins.  When I have a plant suffering from this (funny enough, my lemons are really prone to it here), I pour the pomace blend on the plant.  This does risk giving my plant a disease, of course.   It would definitely be best to grow my own, like Dan talks about above. I do have a Poncirus in, but it hasn't fruited yet. I'm looking forward to having all that sour available!

This technique has brought my lemon and citrus plants back to life. They look amazing after I do this treatment, they get all dark green and shoot out new growth.  With the lemons, I use a surprising amount when I do it (about once a year now).  Like a cup of the stuff for a plant in a 1/2 gallon pot.

As I started thinking about this concept, I realized I had other sources of acidic pomace - hibiscus tea remains being my biggest, sauerkraut or other pickle juice being an occasional one.  

My husband and I drink hibiscus (aka, roselle, jamaica) tea almost every day, we make it from the calyces.  The leftovers are very acidic.  So I make the same blended mix with that and put it on plants that seem to need a boost, more iron or calcium freed up, etc.

Both of these techniques worked much better than applying vinegar, as I have also tried that technique.   Vinegar didn't do much.

So maybe there are other acidic pomaces in one's life that we haven't thought of?  Isn't this the best type of recycling - putting things to use that you previously didn't know had a use?

Douglas Alpenstock wrote:

Nick Kitchener wrote:Provided that there is a health and diverse soil microbiome, the plant will create its own ideal Ph in and around its zoot zone.

Developing a suitable fungal dominated soil structure, and inoculating with a wide spectrum of organisms harvested from healthy soil is a good starting point.

I think there is much truth in that, and it's a goal that lets us thumb our noses at global supply chains. Good.

Still, it's worth considering that the general pH trend in soil is related to the bedrock of a region. For example, the Canadian Shield (granite, naturally acidic) is quite different from the Western Sedimentary Basin (limestone, naturally basic). As a result, techniques for pH adjustment vary.

I happen to live on Canadian shield. The issue there is a high organic matter soil (basically decomposed wood) on top of a (very) hard pan which leads to an anaerobic soil environment because it's basically a foot or two of saturated woody material (peat).

The wild blueberries tend to prefer old forestry cuts where they come in and cut all the trees down and chip the branches. When I dug down to see what was going on, there is a few feet of decomposing woodchips full of fungi and relatively dry. Then there is the original muskeg which is water logged and finally the shield.

The blueberries will tolerate acidic conditions and they do grow in the muskeg, but the biggest, thickest, and most vigorous plants are found in the woodchips.

An old man I used to chat with was very proud of his blueberries. He said he collected pine needles to use as mulch and acidify the soil, and used pine bark mulch as well.

I'd be tempted to start with peat moss or sulphur, and maintain with pine mulch.

I will use pine mulch with blueberries, haskaps, and strawberries to help them along. I'm not sure if it's the acidity or selecting for certain fungi that form symbiotic relationships with these plants is the fundamental reason why they benefit.

I bought my place almost 12 years ago. I have lots of really old pine and juniper trees here along with lots of big bare spots of nothing but dirt and rock. O.K. I also had a whole lot of scrub oak and thorn bushes and dead and dying cactus and agave but never mind that.  The ph of the soil here is super high, over 8 and so is the water.  And I wanted to garden. So I heard what people were saying about pine needles being acidic and wondered if it would be best to put all my beds under the pine trees.

So, if I remember everything correctly, I went to the pharmacy and got some ph paper and started to test the soil in a couple of dozen places in my yard looking for the best spots. Every test showed the same thing. All my soil was 8+ ph. Even the soil under the pine trees covered in years and years of pine needles. Wanted to know why, so I did a lot of research online. 99.9 out of 100 webpages I went to said yes, pine needles would acidify your soil. So why wasn't it doing that in my yard? I finally found just one guy, someone like me who asked the same question. But he was quite a bit smarter than I was. He decided to test pine needles. He took a handful of fresh pine needles, placed them in a glass of distilled water with a bit of dirt and waited for 24 hours. Then he tested them. The ph was just over 5. 4-5 days later he tested them again and they were closer to 6.5. A week later they were looking pretty rotten and slimy and tested them again and they were closer to 7.something. Smart dude. Pine needles are not so very acidic in the long term.

I tried the same test and I got the same results. It explains why my soil under the pine trees and away from my pine trees is all  over 8 ph. Just a special note.... the ph paper cost me about $12. for the roll  and it  only worked well for about 9 months after I opened the foil wrapper. After that it just tested everything as neutral 7.

And Bryant Redhawk has a lot to say about coffee grounds. It's well worth reading.

Happy gardening.

Nick Kitchener wrote:I happen to live on Canadian shield.

Of course you do! That's why I brought it up.  

But seriously, I appreciate your thoughtful comments. Above a certain lattitude, regardless of the bedrock substrate, there are massive peat bogs intertwined with the boreal forest. And we're all concerned about what happens next. Oy veh. My 2c.

Wow, thank you so much, everyone, for all of the great input! This is feeling much more approachable now. Since I am pretty close to the proper pH range anyway, it seems like planting them with a good bit of compost, using some sulfur, and mulching well, would probably be just fine. I love the citrus idea, but we don't use a lot of citrus. I will definitely separate out the peels, when we do use it, though, for this purpose.

If I have happen to have anything acidic to compost or mulch with I will put it there, but otherwise I will just keep an eye on them and apply more sulfur if needed. It may not be a perfectly permie solution, but it still seems better than using large quantities of peat. The fact is, if we don't grow blueberries, we are going to buy them at least occasionally, so better to grow them in the gentlest way we can, than buy them shipped in from who-knows-where.

I think the idea of providing a lot of organic matter is solid no matter what, especially with a woodland-type plant like blueberries. I have lots of punky bits of fallen wood laying around in the more neglected parts of our property that I can mulch with, or even possibly bury between the bushes to make mini-hugels that the blueberry roots can grow into in the future. And can I get some nice leaf mold from those areas as well. It will be mostly oak, but it really seems like when most things compost down they just become pretty neutral, pH-wise, anyway.

I have goats, so have lots of goat manure mixed with pine shavings and hay, but my instinct is to focus more the kind of material you would find in the woods; old wood and leaves, rather than animal manure, and save the goat litter for the veggie garden, etc. My neighbors don't fertilize their blueberries at all; just add peat moss every year.

If I were brave, I would test out the idea of just providing lots of organic matter without adding sulfur or any other acid, like maybe for one or two plants. But blueberry plants aren't cheap, and I just don't know if I have it in me to not give a plant what I think it the best care possible. But I will ponder all of this more between now and planting in autumn.

So here is some interesting info I came across, put out by Texas A&M. It's pretty cool that even a "mainstream" agricultural college is recognizing the need for fungal life in the soil.

Rabbiteye blueberry plants do not
produce the root hairs that are needed
to take up water and nutrients. Instead,
they depend entirely on a fungus that
acts as root hairs for the plant. The plant
provides nourishment for the fungi called
mychorrhizae.

When rabbiteye blueberries are planted in an unsuitable soil or irrigated with
unsuitable water, the fungi usually die,
and the blueberry plant exhibits many
symptoms of nutritional deficiencies.
This type of rooting deficiency cannot be corrected by adding
these nutrients.

Great thread!
I get a lot of citrus from dumpster diving, more than we can use.
I don't like giving the chooks a lot of citrus, so I toss any excess into the one of the barrels that I grow blueberries in.
They rot down slowly, but seem to do no harm to the plants.

I have considered starting a dedicated barrel of acidic waste, but it's more trouble than it's worth.

Howdy folks,
I had a friend that worked many years in the USDA Fruit Lab at Greenbelt, MD. Years ago he told me that while doing tests on a variety of blueberry plants at the lab, they found that by simply adding a few rusting nails (or other small rusty iron objects) to the soil around the blueberry plants, you could continually keep acidifying the soil around the plants, and keep the soil continually supplied with the iron that the blueberry plants like.
When I put in my 1st blueberry bed 20 years ago I added some peat to the soil. Then about 15 years ago I just added a few rusty nails around each plant, and have been having heavy blueberry harvests ever since. Simple solutions like this are not something the peat or soil acidifier industries like to publicize.

It's an intriguing idea. I'm interested in understanding more about how the chemistry and soil science work.

There are perhaps a hundred different forms of iron, and not all are readily available to plants. And how does iron acidify the soil?

I guess I'm looking at a whole lot of moving parts, and wondering if it applies everywhere. Thoughts?

My garden soil is horribly alkaline, so even though I wouldn't attempt blueberries, I've wanted to acidify it a bit. First I bought elemental sulfur from amazon.in. That was hard bright yellow granules, varied sized balls and half-spheres. I mixed some of those into some of the vegetable garden beds, and a year later they are still very bright and visible but they do seem to be breaking down. Then I powdered some in the blender (powerful Indian "mixie) and that at least is not visible in the soil, but then I worried if it might be dangerously inflammable in the mixie (remembering a yellow flash in chemistry class? Not sure) so I quit doing that and just used the granules as purchased. Powdering it made rock hard deposits on the blades of the mixie, that were hard to clean.

At the same time, I had access to dried out cow dung, so I buried a lot in the vegetable garden beds last year. Honestly the beds with more cow dung did better, regardless of the sulfur I added in some beds. So I think I'm going to mainly go ahead with more manure and try the rusty nail thing mentioned above, too.

I primary use coffee grounds, and occasionally with man made stuff.

Very interesting– especially about the citrus. I make lemonade & limeade by liquifying the fruit with water in the Vitamix. I then strain out the thicker bits and never found something useful to do with the goo left over. I have a Synsepalum plant (miracle fruit) and they like acidic soil, so I'll start saving the goo  in the freezer and periodically water it into the pot with the plant!


If anyone has another idea for the goo, I'd love to hear it.
Thanks so much.

Hello clever and beautiful people. I have some blueberries I need to transplant (we have fairly heavy clay soil), but would prefer not to have to use peat due to its environmental cost. What have other people used or have heard about to both acidify and lighten the soil? Bonus if I can also use it to store dahlia tubers over the winter.

Thanks,
Daniel

Douglas Alpenstock wrote:It's an intriguing idea. I'm interested in understanding more about how the chemistry and soil science work.

There are perhaps a hundred different forms of iron, and not all are readily available to plants. And how does iron acidify the soil?

I guess I'm looking at a whole lot of moving parts, and wondering if it applies everywhere. Thoughts?

In my understanding, blueberries don't need acidic soil per se, but acidic soil makes iron more readily available. Blueberries, being heaths, are adapted to acidic, waterlogged soils. Here, there is little oxygen, so iron occurs as reduced iron II which is more available to plants than the oxidized iron III. Acidic soil also causes iron to be reduced (I believe because H+ has a lower reduction potential than OH-, but not sure).

That's why adding rusty nails or other iron to the soil can help. It doesn't acidify the soil so much as it increases the total amount of iron available.

It's also why a lot of organic matter is necessary for the blueberries. As fungi decompose the OM, they release organic acids which acidify the soil. But also, the leftover humus increases the cation exchange capacity of the soil, allowing it to hold more iron. And decomposition can produce chelates, organic molecules which solubilize iron and allow it to move closer to the plant roots.

I hear that for these reasons, you can get away with a higher pH for blueberries if you have healthy soil.

Please correct me if my understanding of any of these parts is wrong!

see https://acsess.onlinelibrary.wiley.com/doi/10.1002/crso.20019

what I do with mine is mix in some of the wood mulch that I get from other parts of my property that is a lot of chewed up oak and/or pine. I need to test/retest my soil a bit, but so far I have done it at this home and my previous home and both had the blueberries doing well with it that way.   I can make wood chips for a lot cheaper than bags of peat moss for sure.

Some people use vinegar or beer to acidify soil gently.  Not sure the exact ratios but you might look into it.

I agree with the pine needle / coffee ground skeptics. They seem to lose their acidity during decomposition. I have hedge rows of pine trees that have been dropping needles in the same place for at least 25 years. pH is 7.0 in those hedgerows and in neighboring areas that don't get pine needles. Whatever happens, I bet it is the same with coffee grounds. I use elemental sulfur to acidify for blueberries.