Seed germination blankets provide a way to re-seed bare spots in the lawn with an increased chance of success. Germination blankets allow light and water to reach seeds underneath them so they will sprout. Blankets also warm the soil to germinate seeds more quickly. Seeds may be washed away by heavy rains, but seed blankets hold the seeds in place so they do not wash into one spot, sprout in clumps and leave other areas bare. A seed blanket also protects seeds and emerging blades so animals and birds do not eat them. These types of blankets can be used in sparse areas over existing grass to help your lawn fill in evenly.