Why Knowing Your Soil pH is Important
By Shirley Martin
Understanding your soil pH can be the difference between a plant flourishing or failing. Soil pH is the measure of acidity and alkalinity, ranging from 0 to 14. Anything below 7 is considered acidic and measurements above 7 is alkaline while 7 is neutral. Most plants prefer a soil ph between 5.5 and 7.0.
So why is it important? pH influences how easily a plant can access nutrients in the soil. If you have, for example, a blueberry plant and your soil is alkaline, the blueberry plant will have a tough time accessing the nutrients it needs to survive, let alone thrive. Blueberries do best in soils with a pH of 4.0 – 5.3.
pH is short for Potenz hydrogen. Potenz is defined as the potential to be. Hydrogen ions in the soil are more plentiful in acidic soil and less present in alkaline soil. The presence of hydrogen affects the nutrients available. Some nutrients are readily dissolved in a soil water solution, so if the soil is too acidic or too alkaline, the nutrients won’t be readily available. In an acidic soil (below 6.0); nitrogen, phosphorus and potassium are not readily available for plant roots to uptake. In an alkaline soil (above 7.5); iron, manganese and phosphorus are not easily accessible for roots to uptake.
Environmental factors may affect your pH. The type of rock beneath the soil can determine the pH. If you have limestone in your area, your soil will be more alkaline. Rainforest areas tend to be more acidic while drought prone areas tend to be more alkaline. Rainfall and temperatures play a role in soil pH. Soil in the midwest with light rainfall and prairie native plants tend to have more neutral soil. It’s a rather interesting science in manipulating pH.
Adding soil amendments like compost can alter your soil pH. Sometimes it is easier to make a raised bed for acid loving plants like rhododendrons, blueberries and even potatoes. Compost will bring your pH closer to neutral. Peat moss will make your soil more acidic, though there’s the argument that the peat bogs are being depleted. You may also use shredded leaves, an acidifying fertilizer or aluminum sulphate to lower your pH. To make an acidic soil more alkaline, add lime or wood ashes.
To find out if your soil is acidic or alkaline, you may purchase a pH meter to test it yourself or take it to a reputable soil lab for testing. Knowing your numbers will help determine to what extent, if any, you need to include additives. The simplest thing to do is determine your pH and grow plants that love that level of potent hydrogen.