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What is Mulching?

The application of grass hay or straw as a protective cover over seeded areas. The purpose is to reduce erosion and aid in revegetation or protect bare soils that will be landscaped later.

When Should Mulching be Used?

Use this method on slopes that have a high potential for erosion. Mulch forms a loose layer when applied over a loose soil surface. To protect the mulch from movement by wind or water, it must be punched into the soil or covered with erosion control netting. The mulch should cover the entire seeded or bare area and extend into existing vegetation or be stabilized on all sides to prevent wind or water damage that may start at the edges.

Methods and Materials

Grass hay or straw mulch can be applied by hand broadcasting to a uniform depth of about two inches. When applied properly, approximately 20-40 percent of the original ground surface can be seen. The application rate per acre should be about two tons (or one 60-pound bale per 650 square feet). Although grass hay works the best for this purpose, clean rice, barley, or wheat straw may also be used. You could also hire a contractor to grind the mulch using a tub grinder and then blow the mulch out over the slope with another piece of equipment.

Most landowners can obtain the equipment to anchor the mulch by hand punching or using erosion control netting. However, you may need to hire a contractor for roller or crimper punching and for hydro-mulching.

Hand Punching

Use a spade or shovel to punch straw into the slope until all areas have some straw standing perpendicular to the slope and embedded at least four inches into the ground. The mulch should be punched about every 12 inches.

Erosion Control Netting

Erosion control netting is used on large, steep areas that cannot be punched with a roller or by hand. Jute, wood excelsior, or plastic netting is rolled out over unpunched straw and installed with manufacturer-recommended staples or staked down. This material can be purchased from a construction material supplier.

Roller Punching

A roller equipped with straight studs not less than six inches long, from four to six inches wide, and approximately one inch thick is rolled over the slope. You may need to hire a contractor for this task.

Crimper Punching

Crimper punching is like roller punching except the crimper has serrated disks about four to eight inches apart that force straw mulch into the soil. Crimping should be done in two directions with the final pass across the slope, if possible. You may need to hire a contractor for this task.


This practice is a two-step practice that applies seeds for revegetation and then applies mulch with a tackifier or substance that helps the mulch adhere to the soil surface.

Hillside and drainage with straw much and straw check dams.

Mulching and straw check dams were applied at the mouth of this drainage to protect a home from erosion.