Importance of Soil pH and How to Correct It

soil-phSoil pH varies from area to area widely. Some areas have very acidic soil or low pH (usually represented as a value of under 7 on tests), and some areas have alkaline or high pH soils (above 7). Acid soils are known as “sour” soils, and alkaline soils are known as “sweet” soils. Plants generally do best in soils that’s a balance between the two, or neutral pH soil (around a value of 7). However, some plants prefer alkaline soil and some prefer acidic soil. Depending on the general quality of your soil or if you have certain types of plants you want to grow with specific needs, you may need to correct the pH of your soil. Here are some basic tips on how to correct soil pH.

Testing your soil to know where you soil generally lies on the pH scale is a good start. You can get inexpensive kits at any garden center to test. We have a simple to use soil pH meter if you want to give it a go. If you have soil that’s alkaline and you want to lower the pH, ferrous sulfate and aluminum sulfate are the two recommended soil amendments that will help make your soil more acidic. To raise the pH of your soil, lime, or ground limestone, is recommended.

Products for adjusting soil pH differ and it’s best to stick with the recommended application directions usually available on the bag of the product.

More natural methods of correcting soil pH to a more generally plant-friendly level involve simply adding plenty of well-rotted manures and compost to the soil that you plan to grow in- and top dress with plenty of mulches that break down into the soil easily in the spring and fall around landscape ornamentals and in production beds. If your soil remains very acidic and compost isn’t helping, try adding wood ash or oyster shell.

Raised bed gardening is also another way to ensure good soil pH without a lot of work. Simply fill containers and raised beds with plenty of rotted compost and potting soil and add more at the end of each season after growing is done.

PH adjustment and correction is very important for a lot of reasons. Most notably, the pH of soil determines what nutrients plants can use and how fast they can use them. Often, there are some nutrients that become bound in soils that aren’t well balanced and plants can’t take up the nutrients they need to grow well. For example, most vegetable crops need slightly more acid soil to grow well so that they have access to the nutrients they need to quickly produce large amounts of fruit.

Sometimes the reason for adjusting pH of soil may simply be a cosmetic preference, specifically when it comes to the bloom of hydrangeas. Some hydrangeas bloom pink in acid soil, and the same type of hydrangea will bloom blue in alkaline soil. Sometimes, crafty gardeners have gotten both colors, even purple, by playing with the pH of the soil that their hydrangeas grow in. There are specific products sold that you can apply to the soil of your hydrangea if you wish to try- commonly found in garden center stores.

Soil pH is important but not difficult to correct. We hope this article helps you understand the basics better so you can grow better plants!