Soil pH – Why It’s Important & How To Correct It

When it comes to plant health, soil pH plays a vital role. If your soil is too acidic or too alkaline, your plants will be unable to absorb the nutrients they need properly — which means they won’t be able to grow. Measuring the degree of acidity and alkalinity in soil is based on a scale of 0-14. Soil with a pH of 7 is considered neutral, 0-7 is acidic and 7-14 is alkaline. In terms of lawn grass soil, the ideal pH is 6.5 and can be determined by a soil test. If you perform a soil test and the results show your soil could use some adjusting, here’s how to correct it.

Soil pH Correction

  • Always read the product label. Once you choose what product you are going to use to correct your soil’s pH, it’s extremely important to read the instructions that come with the package. Depending on what product you choose, you may need a special spreader for it to be done correctly. For example, one brand of sulfur may be ground more finely than another, which could cause damage to your plants if too much product is applied.
  • Fall is prime application time. Try to make the fall months your annual time to test soil and begin correcting pH. This will help you get the desired results and offer plenty time for the soil to break down for spring planting.
  • Take your time. Correcting the pH in your soil may not happen after the first application. In fact, it could take up to a year or longer to get your soil back on track. Make one application of the product and then wait at least three months to retest and reapply if needed. If you apply too much product, it could overdose your soil which does more harm than good.
  • Be mindful of what you plant. When selecting what plants you would like, it’s best to choose those that are suited to the soil you have. You can tweak the soil pH to better growing conditions, but the overall makeup of soil pretty much is what it is.

Acidic Soil

  • Lime. Limestone is a commonly used soil additive that helps raise the pH level . There are usually two types: calcitic limestone and dolomitic limestone. Calcitic limestone is mostly calcium carbonate, while dolomitic limestone adds magnesium to the soil. Each type works well at raising soil pH. When choosing a product, you will notice that liming products come in granular, hydrated, pelletized or pulverized forms. Despite which product you choose, it’s important to know that they all work better when worked down into the soil, rather than being left on top.
  • Wood ash. If you want to take a more organic approach to making your soil less acidic, sprinkle about 1/2″ of wood ash over the soil and mix it about one foot deep. Choosing this route requires smaller applications over several years, but it is very effective.

Alkaline Soil

  • Sulfur. Elemental sulfur (or sulphur) may be the easiest and most common way to make your soil more acidic. Sulfur is cheap, relatively safe and can be spread on top of soil. It is does act slowly, so be sure not to apply more than 2 pounds per 100 square feet at a time.
  • Aluminum sulphate and Iron sulfate. Each of these products acts quickly. However, they can also cause the most damage by adding salts and elements that can build up in your soil. Be mindful when applying and only put no more than 5 pounds per 100 square feet.
  • Sphagnum peat. Another great organic solution is sphagnum peat. It adds organic matter to the soil and increases water retention. Work a 2″ layer of the product into the soil that is at least a foot deep. If you are adding it to a larger area, it may require the use of a tiller.
  • Mulches and Compost. When organic matter breaks down, it can make soil more acidic. Using organic compost and mulches over an extended period of time will help make your soils pH level closer to a neutral or slightly acidic level.
  • Acidifying fertilizer. If you use a fertilizer that contains ammonia, urea or amino acids, it can have an acidifying effect on your soil as time passes.