Having your garden soil pH in the proper range for the plants you’re growing is important. Soil pH defines whether your garden is composed of acidic soil, alkaline soil or somewhere in between.
Why is the pH of soil so important?
Simply because different plants prefer different pH levels.
In fact, some plants are quite sensitive to the pH of soil – so much so that you’ll be wasting your time and effort in trying to grow them if your pH is out of their comfort zone.
A pH primer
Not sure what ‘pH’ means? A simple definition of pH is that it’s a scale used to measure the acidity or alkalinity of something. (And in case you’re wondering 'just what does pH stand for' – it’s an abbreviation for ‘potentiometric hydrogen ion concentration.’)
On the pH scale, which ranges from 0 to 14, 7 is neutral – neither acid nor alkaline. Anything less than 7 is acidic. And the lower the number, the more acidic. Conversely, anything above 7 is alkaline, and the higher the number, the more alkaline. (Something that’s alkaline is also called a base, or basic.)
The pH scale is logarithmic, not linear. Each whole number on the scale represents a 10-fold decrease or increase in intensity.
Something with a pH of 5, for example, is 10 times more acidic than something with a pH of 6.
Just to give you an idea of how the pH scale works, here is where a few common items fall on the pH scale:
pH of water
Water may be either acidic or alkaline. The pH of distilled water is 7.0, or neutral. The pH of rain water is around 5.6 if unpolluted. The pH of acid rain, of course, is lower, depending upon the degree of pollution.
ph of vinegar
2.4 to 3.4 (depending upon the type of vinegar)
ph of orange juice
3.3 to 4.2
ph of blood
7.35 to 7.45
ph of milk
ph of coffee
Usually around 4.0 to 5.0, though some types can be above 5.0
ph of baking soda
How the pH of Soil Affects Plants
The impact of the pH of soil upon the growth and health of plants is indirect, but substantial.
It really has to do with whether the plant is able to get enough of the nutrients it craves. It’s not enough for a certain nutrient to be present in the soil; it also has to be readily available to the plant roots.
And that’s what the soil pH controls.
Because every element is most available for uptake by roots at a certain pH level. Nitrogen, for example, is most available to plants at a pH range of about 6.0 to 8.0.
So if you’re growing a plant in your backyard garden that requires a large uptake of a given nutrient, but your soil pH makes that nutrient less available to the plant, you’ll have problems.
And the reverse situation can also occur, since certain elements are toxic to some plants.
If you’re growing a plant that is sensitive to a particular element, and your soil pH makes that element readily available to the plant, that will also be a problem for you. And again, it’s not so much the fact that a harmful element is in the soil, it’s that the pH helps the plant to absorb it.
That’s why your garden soil pH is so important, and that’s why testing soil pH is worth doing.
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