Gently rolling slopes add visual interest and charm to your lawn. Nothing complements a hillside like lush, green grass covering it. Planting grass seed on hills is not much different than planting it on a level surface. The biggest consideration is preventing the grass seed from getting washed away or drying out due to runoff of water from the hill. Simply plant your seed and cover until it grows, and your slopes will be the envy of all.
Loosen the top of the soil, using a rototiller or aerator to penetrate down 2 or 3 inches. Rake over the soil bed to break up large clumps and remove debris such as sticks, stones and roots. Level slight depressions as you work to create an even slope. Push some soil to the side, to use later for covering seeds.
Spread a starter fertilizer across the soil bed. Mix the fertilizer in slightly by raking.
Mix your desired grass seed with topsoil. Use two parts seed to one part soil.
Divide the grass seed mix in half. Seed the slope, using about 4 pounds of seed per 1,000 square feet. Use a mechanical seeder or seed by hand. Cross the area, going in one direction and scattering half the seed evenly. Repeat the process, going in a perpendicular direction, until the remainder of the seed is disbursed.
Rake across the seeded slope lightly to cover it with soil, protect the seed from birds and ensure good seed-to-ground contact. Make sure the soil is not too thick -- less than 1 inch is sufficient. Follow by watering lightly, avoiding puddles of water.
Cover the slope to retain moisture and hold the grass seed in place. Mulch, straw, or wheat are good choices, and watering will keep these in place as long as necessary. Or purchase mesh burlap, cheesecloth or mesh cloth. Mesh cloth will rot in place and prove beneficial to the soil, but other materials must be removed once the grass emerges. Secure these materials with rocks placed around the edges as needed.
Water grass daily to twice a day; use enough water to keep the top inch or two of soil moist (not soggy). Continue watering new grass regularly, even after it sprouts and the covering is removed, to help it survive until it is well established. Apply a fertilizer 30 days after planting, if planted in spring, and again in fall. Wait until spring to fertilize if the grass was planted in fall.