By Bob Dailey, Master Gardener
Remember the high school science class? No, neither do I, but if I had been paying attention, I would have learned about the “litmus test.”
Here’s how it went, I’m told. First, you dip a piece of litmus paper into a solution, and it turns color…either red or blue. If the paper turns red, then the solution is acidic. If it’s blue, it’s “basic” or alkaline. If you’re interested in what litmus paper is, I think it’s made from lichens. I could go into that a little deeper, but I’m not that interested. If you are, either Google it or send me a message.
The critical point is that it tells you if the solution is acidic or alkaline. Chemists call the range between acidic and alkaline “pH.”
The term “pH” was first described by Danish biochemist Søren Peter Lauritz Sørensen in 1909. The O with the slash is called a “minuscule” by the way, and that’s all I know about it
pH is an abbreviation for “power of hydrogen” where “p” is short for the German word for power (potenz), and H is the element symbol for hydrogen. Why a Danish scientist used a German word is Greek to me, but he was a scientist, and I’m not, so I’ll just go with the flow. The H is capitalized because it is standard to capitalize element symbols. So now you understand about as much as I do.
Chemists and soil scientists have assigned a number to the pH test, ranging from 0 (highly acidic) to 14 (highly alkaline).
Now we know that soil is made up of living and non-living materials, both inorganic and organic. This concoction of components creates some complicated chemistry (how’s that for alliteration). The pH designation and number are considered a “master variable” in soil science.
If I (or you, as the case may be) change the pH of a soil, the process can change biological, biochemical, and chemical processes in the soil and the interaction of those processes.
And here’s how it affects gardeners and farmers.
Let’s use phosphorus as an example. As most gardeners know, phosphorus is one of the three major nutrients that plants need. The other two are nitrogen and potassium. When you buy fertilizer, the law requires that each container on the bag provides the percentage of these three chemicals…nitrogen (N), phosphorus (P) and potassium (K), or NPK.
Phosphorus is an excellent example of how pH can help or prevent plants from taking up nutrients in the soil. Phosphorus is essential to a plant. It plays a role in photosynthesis, transpiration, energy storage and transfer, cell division, cell enlargement, and several other processes in plants. If the pH of the soil is between 5.5 (somewhat acidic) and 8.5 (slightly alkaline), plants can take in phosphorus.
But if the pH is outside those levels (lower than 5.5 on the acidic side or higher than 8.5 on the alkaline side), the phosphorus interacts with other soil minerals like iron oxides and carbonates. This interaction then locks up the phosphorus and make it unavailable to plants.
There is a “Goldilocks Zone” where the pH is just right. That range is between 6.5 and 7.5. This is the range in which most plants can access the nutrients they need.
Plants not only need phosphorus, nitrogen potassium. They need an abundance of other nutrients…minerals like magnesium, sulfur and calcium, as well as trace elements of iron, copper, zinc, boron and molybdenum. Many of these nutrients are already in the soil, but, if the soil pH is outside the “Goldilock Zone”, the plant cannot access the,
How do you find out your pH? Get a soil test done. Here’s where you can go:
Come rain or come sunshine we’re having our annual Fruit & Nut Sale this Saturday. Don’t miss this opportunity to get that fruit tree you’ve always wanted.
Think peach cobbler, peach preserves or juicy peaches all from your own backyard. Our peaches are bare-root and well suited for our area.
TexKing is a variety introduced by Texas A&M and needs only about 450 chill hours to set flower buds. It is an early ripening yellow semi-clingstone peach. TexStar is another variety also introduced by Texas A&M. Mid-Pride has produced consistently in our demonstration garden. Then there is Red Baron with the beautiful showy double red blossoms.
If its Plums you are interested in, we have an excellent selection of varieties that do well in our area. Santa Rosa is the top pollinator for other plums. Catalina is self-fruitful but could use a little help from Santa Rosa. The Methley plum is an attractive tree which is heavy bearing and very attractive.
If you have the space plant a Pakistan Mulberry. It produces 3” long red to black sweet fruit with non-staining juice. It is a beautiful tree all in its own that can reach 30-40 ft.
Our Citrus trees go fast so get there early. Same for the Blueberries.
Check out the Banana ‘Ice Cream.’ It grows to 15ft tall and is hardy to Zone 8-10, well within our range.
Bring your wagon(s). We never have enough.
For a complete list check our website at www.mcmga.com. Sale date is January 25, 2020. Pre-sale program begins at 8:00 am, the sale is from 9:00 am until 12:00 Noon.
We are located at 9020 Airport Road in Conroe. Park at the Convention Center just across the street. Call us for more information at 936-539-7824.
Our Master Gardeners are available to answer your questions!