Sulfur for Lawn Care – How Often Should You Apply It?

So many things can cause your lawn to look dreadful. Bugs, drought, dull mower blades, weeds … they all take their toll. And sometimes, it’s not any of that — it’s strictly the soil beneath the grass. Conducting a DIY soil test, or collecting a soil sample for someone else to test, is the best way to determine what your yard needs. If the pH is high, sulfur can help level it out if applied correctly. Here’s what you need to know with tips from turf expert Jay Worth, who has 14 years of experience in the lawn care industry.

Why Is Sulfar Good for Your Lawn?

“Sulfur is used to correct the pH of very alkaline soils,” says Worth. “Turfgrass of all species grows best when the soil pH is generally between 6.0 and 7.0.” They can block essential nutrients your turf needs from reaching the root zone if your soil gets too alkaline (pH much higher than 7.5), which can result in patchy growth, yellowing and poor health overall.

If your soil’s pH approaches 7.5 or higher, Worth recommends a sulfur application. Sulfar’s benefits include:

Corrects the soil’s pH

“In some parts of the South and Western U.S., there are generally more alkaline soils, sandy or loamy soil, necessitating the application of sulfur to lower the pH,” Worth says. He recommends a soil test. You can buy soil test kits online, at your favorite retailer or local garden center, while online and big box store kits cost $8 to $100.

For a more thorough and accurate test for soil pH correction, contact your state’s university extension service. You can find one near you at the United States Department of Agriculture’s National Institute of Food and Agriculture. Click on your state to find contact information on their soil testing services, including pricing.

“If you’ve done a soil test and know your pH is above that ideal range, when to apply sulfur depends on the grass type you’re growing,” Worth says. “If you’ve got a significant issue that needs correction, your best bet is to make these adjustments over a couple of growing seasons. The alternative is possibly destroying your lawn, so patience is key here.”

Note: The Eastern U.S. features a lot of clay soil, which tends to be more acidic. Applying limestone helps raise the pH to a more neutral level in that case.

Helps grass plants produce chlorophyll

“Sulfur is necessary for photosynthesis,” Worth says. “Plants can’t grow and produce chlorophyll without it.” Most lawn fertilizers include some sulfur (labeled “sulfate” in the ingredients list). You might see ‘ammonium sulfate’ or ‘potassium sulfate.’ If your soil’s pH is a little high, the sulfur in fertilizer can help.

Helps release other nutrients

“When fertilizing your lawn, the plant doesn’t intake those nutrients,” Worth says. “They first adhere to soil particles, and the plants draw nutrients from them.” Generally, sandy and loamy soils hold fewer nutrients than clay soils.

Soil bacteria convert sulfur into sulfuric acid, which releases soil-bound nutrients for plants to absorb. Converting sulfur to sulfuric acid makes more nutrients available in soil that doesn’t hold them well.

How Often Should You Apply Sulfur to Your Lawn?

How often you should apply sulfur to your lawn depends on your turf’s health and soil test results. Applying too much sulfur all at once can damage your lawn.

Generally, apply sulfur once a year. Worth recommends doing it during the fall for best results with cool-season grass types like bluegrass, fescues and perennial rye. For warm-season grasses like Bermuda, zoysia, St. Augustine and centipede, apply during spring before the onset of summer heat.

“Soil permeability plays a huge part too,” Worth says. “If your soil is extremely compacted and you’ve got standing water on your property, sulfur might cause damage. If you think this might be the case, core aerating your lawn before applying the sulfur treatment will help.”

Guide to Using Sulfur Safely

Some soil test results tell you how much sulfur to apply to correct the pH. You may only need a turf fertilizer with sulfur to balance the pH. Or, you might need to apply sulfur once a season for up to three years as part of the best sulfur applications for lawns.

Sulfur for turf comes in dust, wettable powder, liquid and pellet form. Always read the instructions on the packaging for recommended spreader gauge settings, how much to use and whether you need to water it into the soil.

You can buy lawn fertilizer with sulfates as a liquid applied with a hose-end sprayer or as granular fertilizer applied with a spreader. Use a broadcast spreader for lawns 4,000 square feet or more. Choose a drop spreader for lawns with a lot of landscaping and hardscaping and smaller-sized yards.

Caution!

If you apply sulfur to your lawn, keep your children and pets away from the area until it dissolves into the ground. Sulfur has been registered as a pesticide since the 1920s. It can kill insects, mites, rodents and fungi.

FAQs

Is sulfur safe to use on all grass types?

Yes, sulfur is generally safe for most grass types when applied correctly and in proper amounts. Whether you have cold-season grass such as fescue or warm-season types like Bermuda or zoysia, sulfur lowers lawn pH to an ideal range for nutrient absorption. But do check the specific application instructions for your variety of grass.

How can you tell if you are using too much sulfur on a lawn?

Too much sulfur can cause grass to turn yellow, burn in spots or create too acidic of a growing environment in the soil. These are indicators that you used too much sulfur. To avoid this, just stick to the soil test-based recommendations and observe how your lawn reacts after the treatment.

Should you apply sulfur in the summer?

Although it is possible, applying sulfur to your lawn in the summer (especially in oppressive heat) can cause harm to your lawn. For lawns, the best time to apply sulfur is in early spring or fall when temperatures are cooler. If you absolutely have to, apply in summer with caution and do so on a moist lawn for efficiency.

About the Expert

• Jay Worth is a turf and lawn care expert with over 14 years in the green industry, beginning his career in landscaping and sales. He is currently the Marketing Manager at SingleOps and host of the Green Industry Perspectives podcast.

Source

• USDA: “Land-grant University Website Directory”