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  • Does sulfur lower soil pH?

    Created by Larry Harrison on

    HELP! I need to order sulfur to lower my soil pH. My extension agent here in South Carolina is recommending three applications (once in May, July and September) of 20 pounds per 1000 square feet. Your product says, do NOT exceed more than two applications per year. Do you think it would hurt to do three applications instead of two?


  • Author
  • #266093

    Eric Vinje

    Hi Larry –

    The pH of your soil is a measure of acidity or alkalinity. Soil pH is extremely important and directly affects nutrient availability. The pH scale ranges from 0 to 14, with 7 as neutral. Numbers less than 7 indicate acidity while numbers greater than 7 indicate alkalinity.

    To reduce soil pH, or correct alkaline soil, a source of acid is needed. Elemental sulfur is most commonly used by organic gardeners. However, sulfur requires some time before it is converted to sulfuric acid with the aid of soil bacteria. This conversion rate is dependent on the particle size of the sulfur, the amount of soil moisture, soil temperature and the presence of the bacteria. As a result, it can take several months to decrease the pH value.

    To answer your question, I do not think it really matters how many times per year you apply elemental sulfur. However, lowering soil pH too much below the optimum range can be more harmful for your plants than the alkaline soil you already have. Use caution when adjusting pH and do not attempt to change it by more than 1 pH unit per year.

    Hope it helps!

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