Why is pH expressed with numbers on such a weird scale?
Carol Ann Harlos, Master Gardener, answers that question and offers more useful information about pH in this month’s edition of WNY Gardening Matters, produced by the Master Gardeners of Erie County Cornell Cooperative Extension.
The way we measure acidity has to do with the taste of beer, Harlos explains in her article. A slight change in acidity can result in a big change in the taste of beer, so in the early 1900s, a beer company wanted an easy-to-understand system to measure acidity.
Acidity can be expressed as the concentration of hydrogen ions. These are given as numbers like 0.000001 Molar H+.
That’s not easy to understand, so the chemist working on the problem, Dr. Soren Sorenson, decided to reverse things. Put your pencil to the right of the 1 above. Now count how many places you move to the left to get to the decimal point. Six, correct?
Dr. Sorenson spoke French so this was called “pouvoir hydrogène” or the “power of Hydrogen.” In this case the pH is 6.
Read more about what pH means for your soil in the article “Understanding pH.”
On the same page, you’ll find “It’s Not Just the Rain, It’s Also the Snow,” which deals with acid precipitation and what gardeners can do.
Get tips on what gardening tasks you can do now in “This Month in the Garden.”
In the final article, find out about dealing with the Swede midge, which can damage cruciferous plants including broccoli, canola, collard, horseradish, kale, mustard, rutabaga, turnip and radish.