Return to the Soil Forum | Post a Follow-Up

 o
Alkaline clay soil seeking acidic amendments

Posted by Strawberryhill 5a IL (My Page) on
Tue, Dec 6, 11 at 11:46

I was getting horse manure for my roses but will cut down next year since: At various stages of decomposition (6 to 1 year), horse manure tested more alkaline than my clay soil (pH of 7.7 - stables use lime to deodorize their stalls). Also the sawdust and wood chips bedding in horse manure rob the soil of nitrogen as they break down. One University Extension recommends stables adding nitrogen fertilizer to get rid of their horse manure easier.

One web site recommends mixing a bag of pine park mulch with the soil. I was testing EarthGro topsoil pH - very alkaline at 8, but the same soil under a pile of pine barks tested less alkaline after 6 months.

Last year we piled up grass clippings on tomato bed in the fall as mulch, and did not rototille into the soil when spring came. It was the worst crop of tomato in over a decade: verticillium wilt, or root rot took over when we had a wet summer. Other years we rototilled grass clippings in the soil in May and had bumper-crops of tomatoes.

I plan to clip off evergreen branches from neighbor's old Christmas trees and use on my soil. In the past I used evergreen branches as mulch - it worked great in suppressing weeds. Which is better, mixing evergreens with soil, or using them as mulch on rose beds (prefer acidic 6.5 pH) or tomato bed (also prefer acidic soil)?

The Moo manure had been tested alkaline by others, and when I tested in red cabbage indicator, it was as green as baking soda. Do you know of any bagged cow manure or bagged compost/hummus which tested acidic, like pH of 4? Thank you for the info.


Follow-Up Postings:

 o
RE: Alkaline clay soil seeking acidic amendments

I think it would be more reliable to buy some Hi-Yield soil sulfur from the garden store and lower ph that way.


 o
RE: Alkaline clay soil seeking acidic amendments

Sawdust will tie up nitrogen while it's breaking down, but manure is usually very high in available nitrogen so a mix with sawdust is actually perfect. Depending, of course, on the ratio of the two. If a sawdust/manure pile isn't composting (heat is a good indicator) then it may be too high on the sawdust side and needs more browns. But I wouldn't automatically add fertilizer to a pile without seeing how it performs first.

Re: Your question about finding acidic manure: those bagged products vary considerably from region to region and throughout the year. Due to the cost of shipping they use local materials as much as possible. So it's unlikely a product I see here in MO will even be available where you are. Even if it was, it would vary throughout the year with their available inputs.

I second the sulfur or other acidifiers. And oak leaves or (as you suggested) pine will help some.


 o
RE: Alkaline clay soil seeking acidic amendments

The amount of acid gained from organic mater mixed into 8 pH soil is like trying to fill a lake with an eye dropper.
Sulphur is what you need. You still are not changing the soil very deep.
How do I know, I've been there, done that and still battling.


 o
RE: Alkaline clay soil seeking acidic amendments

Thanks toxcrusadr, for the excellent suggestion of oak leaves besides pine needles. I found very good info. from previous post:

RE: Do pine trees make alkaline soil more acidic? Posted by fertilizersalesman z6 PA (My Page) on Mon, Oct 29, 07 at 12:54 "All organic decomposition that takes place in soils (or compost bins) is acidifying. The decomposition process generates acid. If the material being decomposed is full of bases, it is possible that the end result is not acidic. Coniferous trees tend to suck their nutrients back into the tree before dropping old needles (unlike deciduous trees). Pine needles are very different from oak leaves for this reason... yes, pine trees do acidify soil to a certain extent. Plant roots interacting with soils give off acidic compounds."

I agree with fertilizersalesman. There's a Canadian agricultural website that wrote wheat plants give off acid in their roots to ulitize phosphorus in soil. Several sources cited that the decomposing process is what gives off acid - and once it's fully decomposed it tends toward neutral. Very decomposed wood-ash is alkaline.

That explains why I had a bumper crop of tasty tomatoes when I rototilled FRESH grass clippings in the summer, prior to planting tomatoes. But when I composted the grass clippings by dumping on TOP of the soil over the winter without rototilling in, we had root-rot in the summer, and the worst tomato yield.

William Shakespeare rose' leaves were yellowish and stunt in growth with alkaline clay soil. I dug him up, and fixed the soil with 1 gallon of alfalfa meal (pH of 5) and two gallons of peat moss (pH of 6) - he became dark green and vigorous immediately with NPK of 2-1-2 in alfalfa meal and more neutral soil. Roses prefer pH of 6.5, my soil pH is 7.7

Both University of Florida and University of Colorado extensions state that sulfur only lasts for 1 year, and requires annual application. They quoted peat moss lasts for a few years. Fifteen years ago I burnt roots with sulfur and had to replace the soil. When I tried 25% peat moss mixed with native soil - my rhododendrons & azaleas are still healthy green and blooming after many years. The most healthy ones are my white pines: For the first few years they are yellowish. After a decade of fallen needles, they become dark green. I only gave them some blood meal, and that worked better than acid fertilizers.

My front lawn is heavily infested with dandelions despites Scott's weed & feed. My back yard is filled with trees, and I don't even rake the leaves - this area have very little dandelions, much greener lawn. My guess is that the decomposing leaves help my lawn by making it less alkaline for dandelions. I found from previous forum that both oak and maple leaves are acidic. This explains why in my previous house, with many oak and maple trees, we had no problems with dandelions.



 o
Typo mistake: pH of peat moss is 4, not 6

Correction: pH of peat moss is 4, and pH of MiracleGro potting soil is 6 to 6.5 - I haven't done a pH test on wood ash (don't have it), but I would like to know if someone have a well-calibrated meter. The pH meter I bought was worthless, giving false result in vinegar and baking soda. Now I test pH using red cabbage juice, which gives a wider range of colors to judge from. Fish tank litmus paper is OK for testing one's water, but does not give a wide range for the acidic side.


 o
RE: Alkaline clay soil seeking acidic amendments

A study done by Dr. Abigail Maynhard at the University of Connecticut New Haven Agricultural Research Station and printed in a past issue of Organic Gardening magazine some time ago showed that adding Oak leaves or Pine needles to soils did not have a significant affect on soil pH. All of the leaves I have ever tested had pHs in the 3.0 to 3.8 range, but none have lowered my soils pH in the 40 plus years they have been added, on the contrary the pH of this soils has gone from 5.7 to 7.2.
With adequate levels of organic matter in the soil the plants do not show signs of problems, few signs of plant diseases (even powdery mildew) and few problems with insect pests.
The very few posts I have seen that do give a pH of wood ash has it in the 8.0 range. Keep in mind that for centiries people used wood ash to make the lye (a very caustic substance) that reacted with animal fats to make soap.
Litmus papers will only give an accurate reading of pH if what is used to make the solution to test is neutral.


 o
RE: Alkaline clay soil seeking acidic amendments

Wood things tie up nitrogen, but not forever, when it breaks down the nitrogen comes back. Coffee will off set this problem if you used it your compost. Did you try aluminum sulfate? I add it a couple of times a year to offset the alkaline water supply in San Francisco.


 o
RE: Alkaline clay soil seeking acidic amendments

Thank you Kimmsr for the info. on pH. I suspect that organic matters like leaves or banana peels are BUFFERING AGENTS to neutralize pH of either alkaline soil or acidic soil. I boiled red cabbage in distilled water and tested with coffee ground and finely chopped banana peels. The banana peels immediately lighten up the pH indicator juice, and coffee ground took longer, like 4 hours. I'll test red cabbage juice with leaves to see if leaves act as a buffer.

Aluminum sulfate is no longer recommended by University Extensions with its toxicity in plant roots. I checked the blueberry forum and people reported the best success with blueberries planted in alkaline soil are those with plenty of organic matter. The sweetest blueberries I picked are from farms adjacent to woody pine trees. The most bitter and bland blueberries are from clay soil with no trees around.

I planted a cherry tomato in 100% Scott's Premium top soil with peat moss. It was really bland and tasteless. I tested the pH of that bagged soil and found it's more alkaline than mine (pH of 7.7).


 o
Results of pH test on leaves and fresh pine

Thanks tropical_thought for the recommendation of coffee ground to add nitrogen to compost. You are right, coffee ground has NPK of 2 nitrogen 0.3 phosphorus 0.3 potassium. Kimmsr is correct about pH of leaves in the 3 to 3.8 range. When compared to the color change in red cabbage to vinegar (pH 2.4 to 3.4), and it's slightly less pink, which lands it in Kimmsr' measured zone.

When I tested the buffering capacity of espresso ground, it wasn't that good, the solution remained pink. Today I tested used grounds French Roast from Sam's Club (Arabica), and the buffering capacity is EXCELLENT, the solution at first turned pink, but within 1/2 hour it became clear like plain water. Next for buffering is used green teas (it was first neutral purple color, then became more clear). Next is finely chopped banana peels (today I used fresh one, the last time I used 1 week old banana peels, and that worked faster in clearing up the pink solution).

The chopped FRESH evergreen needles doesn't do anything - the purple cabbage indicator stays the same. Finally is chopped maple leaves (2 months old) and I got the BUFFERING result within 1/2 hour - the solution became less pink, and more clear with time. In contrast, the solution with a few drops of vinegar goes from light pink to bright pink with time.

Last year I planted the same cherry tomato in light brown native clay soil mixed with grass clippings - it was absolutely delicious! The same cherry tomato planted in bagged Scott's premium TOP SOIL was so bad tasting that no one ate them - they went to waste. I found that wood ash is commonly used in bagged soil to impart that pitch-black color.


 o
RE: Alkaline clay soil seeking acidic amendments

One lot of Scott's soil likely would be somewhat different from the next lot. Those bagged thingys might be ok to mix with enough good clay loam to get the base minerals from the garden topsoil.


 o
RE: Alkaline clay soil seeking acidic amendments

Interesting thread!

Just wanted to pop in and say that while I don't have an accurate pH value for ashes, it's going to be way higher than 8. Limestone (CaCO3) will make a solution at the carbonate buffer pH of 8.3. The stuff in ash is not carbonates but oxides like CaO, K2O, which in water makes CaOH2 and KOH, very strong bases in the 9-12 range depending on concentration.

Ha, here's a Clemson study of 37 ash samples that reports pH between 9 and 13.5! The scale only goes to 14. Yikes. But the average was 10.4.

http://hubcap.clemson.edu/~blpprt/bestwoodash.html


 o
RE: Alkaline clay soil seeking acidic amendments

Rather then continue using litmus paper to try to determine a soils pH I would contact the local office of my state universities Cooperative Extension Service and inquire about having a good, reliable soil tests done.

Here is a link that might be useful: UI CES


 o
RE: Alkaline clay soil seeking acidic amendments

Below is a link as to the different application rates. In the charts you may want to note that the sulphur is for 100 sq. ft. and the peat moss is per sq. yd.
The prices I found were about $10.00 per 3 cu. ft. (60 lbs.0 for peat moss and $23.50 for 50 lbs. 0-0-0-90 Sulphur.

Here is a link that might be useful: Modifying Soil pH


 o
My native soil is pH 7.7 tested profesionally by EarthCo.

My native soil was tested recently by EarthCo., a professional soil testing company recommended by rosarians. I sent 1 cup of soil from different places of my garden - and got the result back for basic test, plus magnesium, calcium, and other trace elements. They e-mailed me the result with pH of 7.7, super-high in magnesium (to be expected of clay soil), and deficient in iron as expected.

I used red cabbage as pH indicator to test stuff to compare to my native soil. Toxcrusadr is right about wood ash as way past 10, extremely alkaline. My native soil at pH 7.7 is blue-ish purple in cabbage juice, baking soda at pH of 9 is greenish-blue in cabbage juice, and wood ash is 100% green. That's even more green than magnesium oxide (in magnesium supplement). I place magnesium supplement at 10, and wood ash at least a 12 pH.

I checked the 2-months old maple leaves soaked in cabbage juice overnight. It turned strawberry-red, still acidic compared to bright pink vinegar. I tested 2-months old white-pine needles (grind to a powder) in cabbage juice: absolutely no change in color. So it's useless to get Christmas trees from the neighbors, and I wish I had gotten more maple and oak leaves last month.

Thank you novascapes for the info. about modifying soil pH. I like peat moss better because it takes longer to break down, and it loosen up my hardened clay. Environmentally wise, maple and oak leaves do the same.

I like Tropical_thought idea of sulfating the water. My neighbor watered her plants with a soluble fertilizer for acid-plants with Ammonium sulphate, iron .. other trace elements. Her azaleas are robust and deep-green like from the green house. I will try a soluble acid-fertilizer for my roses next year, and will report the result.



 o
RE: Alkaline clay soil seeking acidic amendments

Many people think Oak leaves are acidic while Maple leaves are not but after reading an article about the pH of leaves in an issue of Organic Gardening magazine some years ago I tested some and found I got the same results as the author of the article.
Oak, pH of 3.7
Maple, pH of 3.2
Beech, pH of 3.5
and several others in the same range but I have since forgotten most of them.


 o
RE: Alkaline clay soil seeking acidic amendments

Chasing pH is a futile endeavor. pH is a measure of "free hydrogen" in your soil. As free hydrogen is replaced by anions (e.g. calcium, magnesium, sodium, potassium) the pH rises. At pH 7.0 and above there is no free hydrogen in the soil. A "high" pH is an indicator that one (or more) of these anions is "high" while, in most cases, others will be "low." Get a soil test and find out what's going on in your soil. Correct for it and your pH will naturally fall into an ideal range. By the same token, it's very plausible to have an ideal pH, let's say 6.5, and still have an imbalance of these anions.


 o
RE: Alkaline clay soil seeking acidic amendments

Oops. My last post should have said cations (cat-eye-ons) instead of anions.


 o
RE: Alkaline clay soil seeking acidic amendments

Ayup. In addition to what a soils pH is you need to know why they pH is where it is. What is causing that soil to have that pH?
Another reason why litmus paper or those pH meters are not of much use.


 o
RE: Alkaline clay soil seeking acidic amendments

Chasing pH is a futile endeavor.
Well, that depends on what your goals are, what your pH is and your access to resources. You're trying to push your pH from an 8+ in calcareous clay down to a 5.0 and you're on a budget? Yeah. That's pretty futile.

Now let's say you've got a pH of 7.5 in a sandy soil with no lime and would like to shift it down to 7.0 or even a little acid so that your maple will stop showing symptoms of alkalinity induced chlorosis. Let's also say you have the means to buy some sulfur (and/or iron sulfate) pre-plant and use acidifying fertilizers to keep the pH down over time? Not futile at all. In fact, it's really common.

As free hydrogen is replaced by anions (e.g. calcium, magnesium, sodium, potassium) the pH rises.

Well, not really. pH is not a relationship of hydrogen to other cations. pH is an expression of the relationship between hydrogen and hydroxide (OH-). Note that hydroxide is an anion. That's why you can always calculate your pOH if you know your H+ concentration and vice-versa. You will never be able to calculate your pH from your concentration of other cations.

At pH 7.0 and above there is no free hydrogen in the soil.Actually, if you have a pH of 7.0, that means that the concentration of hydrogen is exactly the same as the concentration of hydroxide in the soil solution. If you had no hydrogen your pH would be 14 and your pOH would be 0.

I think you may be thinking of exchange sites on colloids. If you have a pH of 7.0 or above you may indeed have 0% hydrogen (or actually so close that it is reported as 0% on a base saturation analysis).

Also, you can't raise your pH by just picking a cation and increasing it. That's why you won't get an increase in pH from adding gypsum (calcium sulfate) except under special circumstances.


 o
Oops.

Dang it, didn't mean to hit "submit".

What I meant to say was:

I think you may be thinking of exchange sites on colloids. If you have a pH of 7.0 or above you may indeed have 0% hydrogen on the exchange sites(or actually so close that it is reported as 0% on a base saturation analysis). But that doesn't mean that there isn't any in your soil.


 o
RE: Alkaline clay soil seeking acidic amendments

Thanks for the clarifications, gargwarb. My main point, and I think it's a valid one, is that it's entirely possible to move your soil pH into the "right" range and still have excesses and/or deficiencies. Whereas, if one's soil is properly balanced, the pH will self-adjust. To offer an analogy, if a patient is sick, a doctor can prescribe Tylenol to bring down the fever. This isn't making the patient well; it's simply treating a symptom. Same thing applies to manipulating soil pH.


 o
RE: Alkaline clay soil seeking acidic amendments

Thank you gargwarb for the explanation, you saved me having to attempt it and probably not do as well. :-D And fortyone - agreed on your last post.

Soil chemistry can actually get danged complicated real fast. I'll never forget homework assignments in Soil Chemistry class where we had to write a computer program to figure out the concentrations of cations in the soil water given some starting point. It was not simple.


 o
RE: Alkaline clay soil seeking acidic amendments

it's entirely possible to move your soil pH into the "right" range and still have excesses and/or deficiencies.
Oh yeah, absolutely.

Whereas, if one's soil is properly balanced, the pH will self-adjust.
I suppose it depends on what you mean by "balanced".

To offer an analogy, if a patient is sick, a doctor can prescribe Tylenol to bring down the fever. This isn't making the patient well; it's simply treating a symptom. Same thing applies to manipulating soil pH.

In many instances. But in some you can indeed make a real and permanent change to soil pH. Let's say you have an alkaline soil in an area that is typically dominated by acid soils but limestone happens to be one of the parent materials in this particular area, resulting in an alkaline pH. You can, over time, neutralize all of the lime with acidifying amendments and the pH will hence forth stay down. (assuming you aren't doing something to increase alkalinity, like irrigating with an alkaline water source).

But more typically? Yes, you're right. You'll have to continually make an effort to manage pH.


 o
You betcha

Whoa, Tox. You snuck that one in there while I was typing. :P
Soil chemistry can actually get danged complicated real fast.
100% agree. That's why most of most posts include lots of what I like to call "weasel words" like: 'usually', 'typically', 'however...' etc.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Soil Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here