How Long After Grass Starts Growing Can You Cut It?

First Cut

• When the grass blades are at least 3 to 4 inches tall, the root system is deeper in the ground. Cut the grass, but only remove 1/3 inch of the blade. For instance, if the grass is 4 inches tall, only cut the grass down to 3-2/3 inches. If you remove more than 1/3 inch from the grass blade at one time, you will stress the grass.

More Frequent Cuts

• If you need to remove more than 1/3 inch from the grass height, you can do more frequent cuttings to achieve the desired grass height. For instance, if the grass height is 4 inches and you removed 1/3 inch off the top on your first cut, wait 3 to 4 days, then mow again, removing another 1/3 inch. Your grass blades will then be 3-1/3 inches tall. Continue frequent mowing until you have the height you want or need, but remember to keep the grass blades 2 inches tall all the time.

Fall Mowing

• If you plant new grass seed in fall, you can cut the grass when the blade height is 3 to 4 inches tall, but the first three cuttings will be to remove 1/3 inch of the grass blade each time. For the last cutting of the season, you can mow the grass blades down to 1-1/2 to 2 inches. Shorter grass during the winter will reduce its susceptibility to disease and mold.

Leaves

• Mulch the leaves with a mulching lawn mower during fall or rake the leaves and discard. Leaves left on the grass will smother the new grass and kill it. In spring, you will find bare spots where the leaves left on the ground covered the grass and smothered it.