Grass seed is best mixed with a topdressing and applied directly to the lawn if you don't want to sow or work the seeds into the ground. It is important that seeds are kept moist and it is best to continue to water for 2 or 3 days especially when it has not been raining. While grass seed can grow when it is not been covered, poor germination can be expected and results are usually less optimal. New shoots may not last with a good foundation to begin their journey to a perfect blade of grass . Adding even a thin layer of topsoil, compost, or even grass clippings or mulch can help maintain moisture as the seeds germinate. While oversewing is often encouraged to get thick lush grass, Too much seed, or seeds that are not covered can make it difficult for new grass shoots to access the right amount of important resources such as nutrients from the soil, light energy from the sun, and water.