I Have a Moss Problem on My Fescue Lawn

pH Range

• Fescue grass types, such as tall fescue, grow best when the soil pH range is between 5.8 and 6.5, according to the University of Arkansas. Grass grown below 5.8 cannot absorb the soil's nutrients and or produce dense growth. Moss thrives in acidic soils. Gardeners with moss problems on their fescue lawn should conduct a soil pH test. Spread 50 lbs. of dolomite limestone in the spring and fall per 1,000 square feet if the soil pH range is between 5.0 and 5.5, as suggested by Cornell University. Apply 200 lbs. of dolomite limestone over 1,000 square feet in four applications for a soil pH below 4.9.

Thatch

• A thick thatch layer more than 1/2 inch promoted moss growth. Thick thatch traps soil moisture and provides moss with the moist conditions that it needs to grow. Cut a 2-inch wedge piece of your fescue turf and check the thatch layer. Measure the brown, spongy, organic material in between your soil and grass blades. Dethatch your lawn if the layer is more than 1/2 inch. A power dethatcher removes thatch and moss. A power dethatcher can get rid of 75 percent of your moss, according to Oregon State University.

Water

• Gardeners typically start watering their fescue lawn in April and stop in October, according to the University of Arkansas. Over or under watering the lawn during these months promotes moss growth. If grass dries out in the summer, moss grows back faster than the lawn when you apply water, according to Oregon State University. Giving your fescue lawn 1 inch of water a week, as recommended by the University of Arkansas, prevents moss growth. Avoid watering the lawn if there has been more than an inch of rainfall that week.

Fertilizer

• Fescue grass needs fertilizer for dense growth that competes with moss for the soil's nutrients. Fertilize your fescue lawn in September with one to 1-1/2 lbs. of slow-release nitrogen per 1,000 square feet. Water the lawn immediately after fertilizing to prevent burning the fescue grass. Apply fertilizer again in November in the same amount. Stop fertilizing for the year, as you can encourage new growth susceptible to winter injury.