Starting a lawn from scratch can be a challenging endeavor, especially if you are seeding a large area. Grass seeds germinate best in loose, non-compacted soil that is kept consistently moist. When seeding on a hill, you have a few more things that can go wrong. A heavy rain can wash the seeds down the slope, and a strong wind can blow the soil and seeds away easily. Protecting the seeds from erosion is crucial to establishing a thick lawn on a hill.
Loosen the soil on the hill. Depending on the condition of the soil, a garden rake may be all you need to loosen it. If it is overgrown with weeds or compacted, you may need a rototiller to loosen the soil. Once the soil is loose, rake it smooth with a garden rake.
Set the dial on the broadcast spreader to the setting indicated on the grass seed bag. Each brand of spreader goes by a different "numerical setting." The grass seed bag will list the number each particular brand of spreader should be set to. Pour the grass seed into the hopper of the broadcast spreader.
Push the broadcast spreader across the hill. Walk all the way across the hill lengthwise, and then walk back next to the first path lengthwise. Repeat this process until the entire hill is covered with grass seed. Rake the seeds into the top 1/8 to 1/4 inch of soil.
Fill a lawn roller approximately half full with water and roll the entire hill to press the seeds into the soil. Pushing the roller lengthwise across the hill will be easiest. Seed-to-soil contact is important for good germination rates.
Unroll your grass seed mat across the hill. The seed mats will prevent the seeds from washing down the hill and also prevent wind from blowing them away. You will likely need multiple rolls of the product to cover the entire surface. Secure the seed mats every few feet with garden staples.
Set up sprinklers and water the grass two to three times per day for a duration of five to 15 minutes each cycle. Keep doing this until your grass seed germinates. Reduce watering to once per day for 15 to 20 minutes when germination occurs.
Mow your grass once it reaches 3 to 3 1/2 inches in height. Mow it to a height of 2 to 2 1/2 inches, and reduce watering to your regular irrigation schedule.