Slopes with varying angles are prone to soil erosion. Controlling the soil from running down the slope may prove to be problematic in establishing some form of vegetative cover. According to the University of Minnesota extension service, growing grass on the slope may entail planting two types of grass seed. The most important factor is to quickly establish a green cover over the slope, to prevent the soil from washing downhill. Perhaps the fastest growing grass for ground cover is annual ryegrass.
Begin seeding the annual ryegrass at the top of the slope. Work across the full face of the slope in bands that are 3 feet to 4 feet wide. Broadcast approximately ¾ of a pound of ryegrass seed per 1000 square feet of area.
Rake the seed into the soil, with the tines of the garden rake, in horizontal strokes across the face of the slope. This will aid in covering the ryegrass seed with soil.
Layer straw over the broadcasted and raked seed. Use approximately 100 pounds of straw per 1000 square feet. In most cases, the ryegrass seed will begin to germinate and work up through the shallow layer of straw seven days after the initial planting.
Broadcast the perennial grass seed onto the straw. Local rainfall will work the perennial grass seed down under the straw. The seed will also catch into the quickly growing ryegrass seed. Amounts of perennial grass seed will depend on the variety and species of the grass.
Allow the ryegrass to fully mature and die back naturally. The ryegrass blades will add organic material to the soil on the slope. The perennial grass seed will then take over.