Ben Meadows Blog

Soil pH: Raising or Lowering?

Soil pH is obviously very important for healthy plant growth. We have a variety of soil pH testers and test kits to aid in determining the pH of your soil, and we have learned, from our own personal experience as well as from chatting with our customers, a few tricks to manipulate soil pH to provide a healthier environment for plants.

Soil pH can be lowered to a more acidic level by adding materials such as wood chips, leaf mold, sawdust or composted leaves. Sulfur may also be used to lower the soil pH. The amount of material used depends on the amount of ground and the type of soil you are dealing with. For example, by adding approximately 1 oz. of ground rock sulfur to one square yard of sandy soil (3.5 oz of sulfur per 1 square yard of clay soil) you can reduce the pH of the soil by approximately 1.0 point.

Bone meal, crushed oyster shells, and crushed marble are three substances that can be added to soil to increase the pH to a more alkaline level. In extreme cases the pH can also be raised significantly by adding lime. Again, the amount of lime that you add depends on the area of ground and the type of soil. For instance, you would add approximately 4 oz. of hydrated lime per one square yard of ground, if you are dealing with sandy soils, to raise the pH by 1.0 point. This ratio should be increased to approximately 12 oz. of hydrated lime per one square yard of ground to raise the pH by 1.0 point if you are working with clay soils.

pH changes in the soil take time because each unit change in pH is a 10-fold difference in acidity or alkalinity, so it is best to change the pH over several seasons. In cases of extreme pH in the soil it may be better to do your plantings in a raised bed, rather than adding mass amounts of chemicals to the soil to raise or lower the soil pH.

Does anyone have other ideas for getting more successful plantings? Other tricks to alter soil pH?