New turf is ready for mowing two weeks after installation or when the grass is taller than 3 1/2 inches, whichever comes first, according to Green Valley Turf Co. The grass must not be cut shorter than 2 inches high the first few times it is mowed.
New turf needs a large volume of water to take root properly, but the grass needs to be dry before its first mowing. The turf also must be stable enough to tread on without leaving footprints. The turf roots may not be strong enough to stay in place during the first mowing, but some shifting is acceptable as long as the turf pieces are put back in place, according to Green Valley Turf Co.