Your soil is acidic and you would like to change the pH so that it is less acidic. The universal advice is to add lime to the soil ie liming your soil. Lime is alkaline and it will neutralize the acidity of the soil and make it more neutral. Adding lime certainly works – but there is a catch!
What is Lime?
Strictly speaking lime is calcium oxide or calcium hydroxide, but the term is also used to describe a wide range of calcium-containing compounds. Agricultural lime is usually calcium carbonate, or limestone. All of these soil conditioners will neutralize acids and make them less acidic.
Liming – What Happens in the Soil?
Soil is able to ‘buffer’ itself. What this means is that you can add a bit of lime to acidic soil, and the pH of the soil does not change. This ability of the soil to neutralize the lime is called ‘buffering’. If you keep adding more and more lime, you will reach a point where the soil just can’t buffer any more, and the pH will start to go up. How much does your soil buffer? That is an important question when adding lime because you need to add enough lime to overcome the buffering effect and then add more to change the pH.
The buffering effect of soil can be measured and it is called the “Buffer pH”. Without knowing the Buffer pH, you simply do not know how much lime to add to your soil.
How do You Measure Buffer pH?
A commercial soil testing lab can measure and report the “Buffer pH”. Using this value it can then recommend the amount of lime you need to add to the soil.
In a previous post I discussed the accuracy of soil testers in Soil pH Testers – Are They Accurate?, but an even bigger problem with these testers is that they don’t measure Buffer pH.
Since garden soil kits don’t measure the Buffer pH, they aren’t much use for adjusting the pH of acidic soils.
Liming Lawns
A lot of gardening information recommends that you should add lime to your lawn on a regular basis. As you can see from the above discussion you can’t know how much to add without a soil test. Don’t add lime to your lawn unless a soil test tells you that it is required.
If you are trying to get rid of moss in your lawn because of the acidity have a look at this post; Why Does Moss Grow in My Lawn?
Robert is actually correct in this sentence. I am a scientist and have done many studies (lab and field) relating is to soil properties and the effects varying nutrients in various measured amounts, as well as a variety of additives and the relevance it had in the growth of the vegetative matter. Although it doesn’t fertilize, it does permit the soil to be more prone to absorption of nutrients that are essential (the three macronutrients listed), however it is also nice to know that certain species of plants actually thrive in acidic soil‘s such as hydrangeas if I’m not mistaken. Either way, any matter that is supplied with certain elements benefit the plants through soil additives that allows one to adjust the soil pH (similar to the SUPPLEMENTS that raise pH and lower pH) though based on what you plan on growing, it’s nice to recognize the species that prefer acidic soils and if one is having to add calcium carbonate to their soil often, why not go to the local community composting center and get neutral, fertile and organic matter for cheaper than a single application of lime And you would be capable of acquiring a yard for a dollar or a full trailer for $11-$15… raise it half a foot and you’re good or look for matter that thrives in acidic soils… thank you 🙏
wow. people love to fight about everything!–even lime!
Does liming the lawn with burnt patches due to dog urine?
Thanks
Ash
Damage from dog pee is from high nitrogen levels, not acidity. So liming won’t work. Best thing you can do is water the spot right away.
Fine Dolomite lime has a neutral ph of 7. Please stop feeding lies to people.
1) The article never even mentions dolomite lime.
2) As a solid it won’t have a pH – so you can’t say it is pH 7.
3) Adding it to acidic soil will raise the soil pH, if you add enough.
Jesus Christ River Pavlis take a breath and relax. Maybe some people have acidic soil and lime helps. It’s not the ‘never ending battle ” you make it out to be. The effect of one application of lime can last for years. In general, people aren’t stupid and wouldn’t be adding lime if there weren’t results. Science may reveal the” why’, but that doesn’t negate the value of good advice based on results.
Actually people are adding Lime when it is doing no good for their soil.
I set 10 bags out in order to lime my yard.I had excellent results with my back yard.My problem is that the rain soaked my Limestone bags with water and therefore my Limestone is lumpy,rather than a powder.Can I use these or do I have to buy more Limestone?How do I properly dispose of the Limestone? Sincerely Daniel
You can use it – the chemical ions are still there.
Sorry but I grew up on a farm we always lime are yard in the spring before a rain my grandmother was very adamant about doing so. Her vegetables every year were always plentiful and huge. Also we never had fleas or ticks in the yard and the almanac says same thing.. Sorry but I believe in the old ways and it’s not a myth it’s a way of life for the American Farmers.
You can believe what you want – but this post is based on well established science.
I’ve read evenly taken down a bunch of cedars that have been growing for 24 years. They had to come down for safety reasons. But my soil is acidic and I want to make it more neutral. Is there anything else besides lime that would help with the process? I don’t want the soil to become toxic with an abundance of calcium.
Get a soil test and they will tell you what to add. Why not live with your pH? Changing pH is a never ending battle and rarely worth the effort for home owners. Grow things that love acidic soil.
science is never settled, this is the problem with the world today, quackademics reading from the same old books and thinking that whats in them is set in stone, science is forever changing and for the world and humanity to move forward quackademia must change. problem is if you stray from the mainstream narrative your vilified and dont receive funding.
Gypsum improves the soil in my area in California which is a fine silt that behaves like clay. Gypsum makes the soil percolate water, improves tilth, and adds calcium but does not change the pH. My understanding is that calcium takes the place of sodium, changing the soil’s structural properties, especially when it is heavily watered to permeate the soil and remove sodium. I only know that it works.
Gypsum does work in some soil, but should not be used in many others.
Will lime make the soil more fertile
Lime is a form of calcium oxide. The only part of this that would be used by plants is the calcium part. If your soil is deficient of calcium, then lime would be one way to add this element. However, most soil has lots of calcium in which case adding more calcium will either have no effect, or it might make the soil toxic by adding too much.
Unless you have done a soil test and it shows a lack of calcium, or you have very sandy soil which has few nutriments of any kind, assume you don’t need more calcium.
Hi Rob, i just left a not-flattering comment on another article of yours and now I’m following up with this … You might think I’m trolling you. That’s not the case, I’m researching soil amendments for my poor lateritic acidic soil, hence exploring your site.
Your answer to above comment from Luke, while being technically correct, is so utterly misleading !
Low ph makes a lot of soil nutrients unavailable … Notably P and K. Also N. So if your big 3 macro nutrients are less available in soil due to low ph and adding lime is going to raise the ph, then definitely liming makes your soil fertile !
Raising pH does not make soil more fertile. It can make the existing nutrients more available to plants – but changing pH does not change the amount of nutrients in the soil.
I Find your lack of temper invigourating. Please excuse my Swenglish spelling and do carry on the good work with your publications.