How To Determine When It's Safe To Mow New Sod

Starting a new lawn presents two options — planting grass seeds or laying out rolls of sod. In either case, finishing the project gives you time to literally watch the grass grow, as each method requires some patience waiting until the area is ready to mow. When growing grass from seed, it's easy to note the progress simply by looking at the new grass. Sod is another story. Freshly laid sod may look like a lush lawn from afar, but it's far too new to mow. New sod needs time adjusting and growing into its new home, your yard. Mowing it too soon could harm the fragile sod and make it difficult for the sod to recover. 

New sod is a lot like tiny sprouts of grass that haven't fully established themselves yet. Both sod and sprouts of grass need time to establish roots before they're ready to endure mower blades. Strong roots take time, and the stronger the roots, the better the grass is able to withstand mowing. New sod takes between two and three weeks to establish itself, on average. To determine whether the sod is ready for its first mow, gently tug on it. If it lifts up like a piece of scrap carpet, it hasn't established roots well enough yet. If the sod offers some resistance as you pull it, it's ready.

Of course, even if the sod passes the pull test, it still hasn't had time to establish deep, strong roots, so it's important to take a few extra precautions before mowing. 

Raise the mower blade height so it trims somewhere in the 3- to 4-inch range (or the highest setting). Make sure the blades are sharp; sharp blades perform a clean, straight cut, while dull blades produce ragged cuts, rips, and tears that stress the sod. Sharpen your mower blades if necessary or take the mower to a local repair shop to sharpen them. Skip watering the night before you plan to mow, and don't mow if the sod is soggy, as this could cause ruts from the mower or even harm the sod. If it has rained a lot, be sure to walk over the entire area before mowing to ensure the ground isn't spongy or springy. If it is, it needs to dry out before mowing. 

The roots on your new sod grow stronger over time, so it's still important to let the grass grow a bit on the tall side to give it a little more time between mows. One rule for mowing both established grasses and new sod is to never cut more than the top third off at any time; any more than that causes extra stress on the grass.