What is the best component to decrease the pH of soil?

To decrease the pH of soil, elemental sulfur is the most effective component. When sulfur is added to the soil, it undergoes a biochemical transformation facilitated by soil bacteria to form sulfuric acid, which in turn lowers the pH. This process can take some time, often requiring several weeks to months depending on soil temperature, moisture, and microbial activity.

In contrast, lime is used to increase soil pH and make it more alkaline, while compost and organic fertilizers typically have a neutral to slightly acidifying effect on soil pH but are not primarily used for significant adjustments. Therefore, among the options provided, elemental sulfur stands out as the appropriate choice for effectively lowering soil pH.