Till the ground to prepare the site before you sow the grama seed. You need to kill the other grasses growing or they will compete with the grama grass. If your land is non-lawn, remove all weeds. You can do this by pulling them by hand or by using an herbicide that kills annual and perennial weeds, but does not contaminate the soil. You can also use herbicide to kill the existing grass in you lawn, but you need to leave the land idle for a month or more. Then you can rototill the ground to work up the ground and combine the dead grass into the soil.
Water the ground thoroughly and then wait a few weeks. This will germinate the weed seeds so you can go through one more time and kill them with herbicide or pull them by hand.
Rototill the land again to a depth of 3 to 4 inches. Do this right before you are going to sow the grama seed. Level the land with a rake. Raking will also remove any roots, rocks or dirt clods. After you have removed the debris, comb the soil with the rake, leaving little furrows.
Estimate the size of the area you wish to cover with grama grass. If you have an area that is 500 square feet, you will need to mix 2 lbs. of seed with the sand, or you can also use 3 to 4 lbs. per 1,000 square feet. There is no consensus
Fill a bucket halfway with slightly moist sand. Add the amount of grama seed you need into the bucket of sand and mix the two.
Broadcast the grama seed/sand by hand. Once you are done, turn the rake over and, using the flat side, smooth the soil to cover the seeds.
Water the seed lightly and frequently. Keep your newly sown lawn watered until the grama seed has germinated and the grass is 1 inch tall. After that, reduce the amount of watering.