Can You Lay Sod Over Existing Grass?

On its surface, it seems like an easy shortcut: Roll out new turf over a struggling lawn, let the bottom layer die and – viola! – a new, beautiful lawn. While that sounds simple, skeptics will probably ask, “Can you lay sod over existing grass?”

We wouldn’t recommend it.

While it seems like a great idea, layering sod on top of existing turf isn’t likely to fare well unless the underlying turf is very sparse. We can see why you’d think it could be a good strategy – like laying landscaping fabric, sod could starve existing grass for sunlight and effectively kill off the original layer.

Professional turf layers know that’s a recipe for a ruined lawn, for a variety of reasons. Turf needs to be able to grow roots quickly to become established after sod is laid. To do so, it needs additional soil. The original layer of grass will form a barrier that makes it difficult for roots to establish.

You’ll also be unlikely to lay sod in a manner that will prevent its roots from drying out. Because of the air trapped in the original grass, roots will be exposed to air and, regardless of how diligently you water them, will dehydrate.

If you’re in the market to lay new turf over a struggling lawn or playing field, you’ll need to prepare the ground first – exactly how you’d prepare it to allow sod to make root-to-soil contact. You may consider adding a layer of topsoil on top of existing grass, or, better yet, remove old sod with a sod cutter to expose soil.

Many garden centers accept sod cuttings for their mulching project, so call around if you’re concerned about diverting large amounts of yard waste from the waste stream when you re-sod your lawn.

As with any other turf-laying project, you’ll need to consider grading and drainage when you install your new sod, making sure water doesn’t pool in low spots and drains properly.