Mar 9th, 2010
What Is PH?
Do you know what the pH of your soil is? Checking a soil’s pH has become so much easier today with new tools.
Above all, don’t guess at pH. Use an electric bridge device if possible. We tend to assume that all peat, oak leaf mold, etc., is acid. This is not true. The brown runoff from newly fallen oak leaves is acid, but once the soluble tannin has been leached away, the residue is alkaline. The same is true of certain peats. German, Swedish, and Canadian peats are usually acid, but domestic brands may be highly alkaline. Always check your peat for pH before using it. Use a soil test kit, or have the peat tested in a soil laboratory.
Note the comment on tannic acid. There are good and bad soil acids. Tannic acid is good, but aluminum acidity, from the commonly-used aluminum sulfate is bad. The stuff is often recommended because it is used commonly to acidify the soil in greenhouse plants. It works, but at the expense of roots, which are eventually killed by aluminum acidity. This is not important in finishing a hydrangea pot plant for Easter sales, but is fatal to rhododendrons after a year or two.
For acidifying, use sulfur, ammonium sulfate, ferrous ammonium sulfate (see above) or potassium sulfate. Very light doses of magnesium sulfate (Epsom salts) will supply the small amount of magnesium needed for good growth. However, don’t overdo this. Speaking of magnesium, its role in plant nutrition is only recently coming to light. Apparently chlorophyll is actually a magnesium chelate which keeps other elements in photosynthesis moving properly.
We never see calcium deficiencies in the Midwest. Our waters supply lime, often too much. Test the pH of the water as it comes out of the hose, and reduce the alkalinity as necessary.
Find out about more on the topic of short evergreen trees today!
