Why Do You Use Sulfur in the Soil for a Garden?

Sulfur is an element.

Sulfur is an essential plant nutrient. Some fertilizers like ammonium sulfate increase sulfur levels in the soil. In gardening, however, sulfur is typically used to acidify soil that's too alkaline for healthy plant growth.

Features

Sulfur is the 16th element of the periodic table. In its elemental form, it's a soft, yellow-colored solid that ordinarily exists as S8 molecules -- molecules composed of eight sulfur atoms apiece. You can find elemental sulfur at many garden stores.

Function

When added to garden soil, sulfur is oxidized by soil bacteria to form sulfates; in the process, it acidifies the soil, increasing the hydrogen ion concentration. Since many plants cannot tolerate highly alkaline soils, elemental sulfur is one option for reducing soil pH to create better conditions for your plants.

Considerations

Elemental sulfur should never be used to remedy a sulfur deficiency; it's useless to the plants until it's been converted to sulfates by the soil bacteria, whereas a fertilizer like ammonium sulfate contains sulfates the plants can utilize right away. Moreover, applying too much elemental sulfur can over-acidify the soil, creating a new problem in place of the one you wanted to solve. It's best to test soil pH before and after applying elemental sulfur.

References

• North Carolina Agricultural Extension Service: Soil Facts, Sulfur as a Plant Nutrient
• Clemson University: Lowering Soil pH
• Clemson University: Changing the pH of Your Soil