How Does Sulphur Work on Lawns?

How Sulfur Works

• The primary use of sulfur for lawn is to reduce pH levels of highly alkaline soils. When grasses are grown in overly alkaline soil, the availability of many nutrients is affected. The addition of sulfur in soil allows the bacteria in the soil to convert the sulfur to sulfuric acid. This lowers the soil pH through a natural biological reaction that is slower in nature than the more rapid chemical reaction caused by certain other nutrients.

Effects on Grass

• Sulfur helps to encourage a lush green color of grass. The nutrient also helps with healthy root growth. Lawns that have adequate amounts of sulfur have stronger shoots with more dense blades and overall growth. Sulfur helps to elevate the levels of carbohydrate reserves in the lawn and reduces susceptibility to common lawn diseases. Lawns that are inadequately amended with organic material are usually more prone to suffer from sulfur deficiency.

Signs of Deficiency

• Though it is best to conduct a soil test to determine sulfur requirement, deficient lawns also start to display physical symptoms of low sulfur in soil. This includes the discoloration or yellowing of older grass blade. Lawns become slow growing and younger grass is slow in maturing. Grasses that are planted in sandy soils are likely to suffer from problems related to insufficient sulfur.

Application Recommendations

• Use about 2 to 3 pounds of sulfur for 1,000 feet of grass per year. It is also a good idea to choose a lawn fertilizer that already contains sulfur as this makes application easier, suggests the Washington State University Extension website. Water lawns well after sulfur application and avoid using excessive amounts as this can burn grass roots. Commonly used sources of sulfur include gypsum with 18.6 percent sulfur, potassium sulfate with 17.6 percent sulfur, ferrous sulfate with 18.8 percent sulfur and ammonium sulfate with 24 percent sulfur.