Some Geeky Talk about Soil Acidity

Let’s talk about chemistry. This isn’t going to be one of those annoying personal ads that keeps landing in your inbox even though you have been married for seven years. I am assuming most people know the PH scale but let’s review just in case. Because I am a geeky wannabe and it’s fun. No, really. It is. Trust me. Ok, I will try to amuse you best I an.

pH stands for “potential Hydrogen” and is a measure of hydrogen ions in the soil. The more ions the more acidic the soil. pH is measured in a logarithmic scale. Meaning a pH of 5 is 10 times more concentrated than a pH of 6. A pH of 3 is 1000 times more acidic than a PH of 6.


The scale for pH goes from 0-14. 0 is the most acidic you can get. Battery acid or an ex-boyfriend would be one example. On the opposite side at a pH of 14 is the most basic you can get. Drain cleaner would be at this end of the scale. pH of 7 is neutral. Pure water has a pH of 7. Anything under 7 is acidic, anything over 7 is considered basic. Or if you are a more visual person:


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0 7 14
Burn your face off not doing much Hella basic

A couple of examples: Stomach acid pH 1, Coke pH 3-4 (one reason it rots your teeth), blood somewhere around pH 7.3, household ammonia around 11, oven cleaner (sodium or potassium hydroxide) around 14.

Soil has a lot of different elements including: Phosphorous, Potassium, Calcium, Iron, Copper, Sulfur, Boron, Magnesium, Manganese, Molybdenum and Nitrogen Try saying that 5 times fast, especially Molybdenum. Silicon, Aluminum, and mostly-bound Oxygen; these three make most of the earth’s crust, but they are more of a medium than active participants). Certain plants need different amount of these elements. Phosphorous is available to plants at a PH of 6.0-7.0 and Nitrogen is available at soils with a PH greater than 5.5. Most of these are pretty happy in the 6-7 range. Happy plants are productive plants, I hope.

Incorrect soil PH can tamper with the ability of your soil to provide nutrients. Ever seen yellow leaves on a plant that ought to be green? Sometimes that is caused from an Iron deficiency. The Iron becomes trapped in a form the roots can’t use. So I on the neighbor hood watch program with my blueberries for signs of yellow leaves since this is a problem in alkaline soils, aka where I live.

There is a whole bunch of geeky stuff that goes into this but that serves our purpose for now.


Most food crops prefer a slightly acidic soil. Fantastic you say, I live in clay soil (basic). (Much of the US from the Appalachians to the Rockies is clay... Clay is made mainly of hydroxides, which are the basic. Not fun for blueberries.) That’s ok, you can modify you soil over time to conditions that your plants will favor. Potatoes, strawberries and blueberries prefer a more acidic soil, while things in the brassica family (something we people with a thyroid condition should mostly avoid) prefer slightly alkaline conditions. Plants in the brassica family include broccoli, cauliflower, brussels sprouts, cabbage, kale, and wild mustard. Yup, kick us while we are already down.

It is important to test your soil PH to know what you are dealing with if you have plants that have high acidity needs such as blueberries. Strawberries are more forgiving, at least they seem to be since I can grow them here and my soil is between 7-8 for PH range.

All these ways take time and my least favorite thing…patience. Really I need to find a better past time for those of us that prefer instant gratification.

An easy way to acidify you soil is to add sulfur. I think it is better to use than Aluminum Sulfate, at least that is what I read somewhere at. I used the Organic Traditions Soil Acidifier. I got mine from Lowes but they sell it at Home Depot and on Amazon. It seems to be working as my PH has gone down about 2 since I started the process.

Organic Matter like compost is great for adjusting soil PH. I am going to make a barrel composter hopefully this winter as a project.

Lime: used for making acidic soils more alkaline. This is not an issue here so this might be the last time you see me mention it.

Wood ashes: also effective at raising PH but not as good as lime.

Peat moss: Supposedly goes acid when it degrades. At least that is what they told me. As an aside, peat bogs are pretty acidic, enough that people have found mummified human remains. So in other words, hide the dead body elsewhere. Robin, my uncle’s girlfried, suggests dumping at sea in an area with lots of fish or having crabs eat them. Apparently they are quite voracious. I have also heard the same thing about pigs. Just get rid of the teeth. Bet you didn’t expect murder tactics on this blog. I digress, a lot, just one of my many charms.

I have been using test strips with varying success. Anyone have a soil PH meter they love that doesn’t require a calibrator? I found some on Amazon but the reviews aren’t stellar.

I have been using pH paper with some mixed results. The picture doesn't show the colors as well as they came out but my normal soil is between 7 and 8. The pH of 7 is my water and the strip on top is my blueberry bed. I just started composting so it will be interesting to see how that changes the soil acidity in the future.