Successfully growing plants, especially edible produce, in your garden takes hard work and a good understanding of the growing conditions your plants need. It’s a little bit of science and a little bit of art all rolled into one. One of the biggest science components is related to soil pH and making sure your soil is in the proper range. Don’t worry though, once you have a general understanding you’ll be well on your way to testing the pH of your garden soil and keeping it where it needs to be!
What is soil pH?
Soil pH is a measurement of how acidic or basic (also known as alkaline) the soil is, like the acidity we are familiar with regarding liquids.
pH – the potential of hydrogen – measures the concentration of hydrogen ions, both positively charged hydrogen ions (H+) and negatively charged hydroxyl ions (OH-) in an environment. More positively charged hydrogen ions creates an acidic environment; a greater amount of negatively charged hydroxyl ions produces an environment that is less acidic, or basic.
The acidity or alkalinity of something is measured on a logarithmic scale ranging from 0 – 14. Values increase or decrease by a factor of ten when there is a change in one full numerical unit. This means that a soil with a pH of 5 is ten times more acidic than one that has a pH of 6, even though the value only changed by one.
Values on the pH scale are broken down to distinguish the relative acidity or alkalinity:
- 0 – 2 is strongly acidic.
- 3 – 5 is weakly acidic.
- 6 – 8 is considered neutral.
- 9 – 11 is weakly basic.
- 12 – 14 is strongly basic.