A lawn roller is a huge help when you're establishing a new lawn. Before sowing grass seed, rolling the soil levels the ground and helps eliminate low spots and clods of soil. After sowing the seed, rolling ensures all seeds are in contact with the soil, which helps speed up germination. Rollers are also used when installing sod. Once the sod is laid, a lawn roller removes air pockets and ensures the roots are in contact with the soil beneath, which helps the sod become established.