When to First Mow After Seeding New Grass

Wait until new grass grows one-third taller than its recommended mowing height before cutting it for the first time.

It can take a period of several weeks before your newly planted grass seed is ready to be cut for the first time. Cutting it too early can damage the new turf so it's best to wait until the time is right.

Time Frame

Do not mow your newly planted grass until it is at least one-third taller than the recommended height for mowing, the Virginia Cooperative Extension recommends. For example, if the recommended mowing height is 2 to 2 1/2 inches, it should be mowed when it is between 2 3/4 and 3 1/2 inches.

Mowing Instructions

For its first mowing, do not cut more than one-third of the total blade height from the grass, the Iowa State University Extension suggests. Be sure your mower's blade is sharp before cutting your lawn for the first time.

Modifications

If your newly planted grass surpasses the recommending height for its first cutting, you will need to take special precautions. In these cases, cut the grass in stages so as not to remove more than one-third of the blade height, the Iowa extension advises. Wait at least a few days between mowings.

References

• Iowa State University Extension: Establishing a Lawn From Seed
• Virginia Cooperative Extension: Establishing Lawns
• All About Lawns: Planting by Seed