FAQ About Indoor Plant pH and Acidity Management

To lower the pH level of soil, making it more acidic, you can add organic materials such as sphagnum peat moss, sulfur, or aluminum sulfate. Sphagnum peat moss can be mixed into the soil at the time of planting or worked into the top layer of an existing pot. Sulfur and aluminum sulfate can be more rapidly effective but should be used with caution, as over-application may harm plants.