Lawn rollers are hollow drums that are filled with water. Adjusting the amount of water affects the weight of the roller. Rollers can be hand-pushed or may be attached to a tractor for large or sloping areas.
Seeds need contact with the soil in order to grow properly; seedling development is poor in loose soil. Using a roller on a newly seeded lawn ensures this contact, improving germination. Rolling also firms the soil surface and eliminates rough areas.
After gently raking the grass seed into the top 1/4 inch of soil, roll the seed bed with a lawn roller. Use a roller half full of water.