New lawns need time for their roots to become established before they can be mowed for the first time. This process usually takes 10-14 days from the time of installation. When the grass blades are healthy and growing taller, the roots have established well enough to begin mowing. Mowing should be done frequently enough to ensure that no more than 1/3 of the blade of grass is removed at one time. The height of mowing is dependent on the type of turf. The grass clippings don’t need to be collected unless they’re exceptionally long and could smother the grass. Leaving the clippings recycles nutrients back into the lawn, saving on fertilizer costs.