Can You Lay Sod Over Existing Grass?

By: Ken Wilson

Many homeowners are under the impression that laying sod over their existing lawn is an ultimate time-saver hack. We get it; laying sod is a challenging task– so it’s common for people to look for an easy way.

Spoiler Alert: Laying fresh sod on your existing grass is not a shortcut you’d want to consider. This may only harm the growing sod and require twice the effort, time, and money.

Experts are unanimous when laying sod over existing lawns: Don’t do it! And we’re here to discuss why it is a bad idea to do so and why you should consider removing the existing grass before laying the new sod instead.

Is it a Good Idea to Lay Sod over Existing Grass?

For your sod to thrive well, it will need to establish its root system correctly with the right amount of nutrients and water. The faster it takes root, the healthier it will be in the long run.

One of the best ways is to ensure the sod is laid flush against the soil, allowing the roots to grow and the proper nutrients to be soaked up completely. And while laying sod over your existing lawn seems like a pretty sweet idea, it may kill your new sod, especially if the grass can’t make contact with dirt.

Adding a layer of grass below the new sod will only prevent it from taking root. Since the new lawn will most likely lack adequate moisture and nutrients, it may only increase the chances of lawn decline. Moreover, laying sod over existing grass will only interfere with its proper grading. Ideally, the soil’s base must be level with other surfaces (driveways and sidewalks) instead of higher than them. You will need to remove your old lawn before laying the new sod to ensure healthy root system growth to do this the right way.

What Happens if You Lay Sod over Existing Grass?

Laying fresh sod on top of an established grass will only make things difficult for the new sod’s roots to reach the soil bed. If anything, they will need to work harder to penetrate the existing lawn’s root system before it gets the soil.

This will only put a heavy strain on the sod, killing your new lawn in the following weeks. Suppose this happens; you will have to remove two layers of sod to allow fresh grass to take root. In that case, you’ll be dealing with a matted slimy mess that you’d want to avoid as much as possible (Trust us on this!)

Here are some scenarios for when you decide to lay sod over existing grass:

It will be Difficult for the Sod to Take Root

The roots will need to work twice (or thrice) as hard to get to the soil once you lay sod over existing grass. In some cases, they may also be unsuccessful in the attempt. It is common for the new sod to begin turning into an unsightly shade of yellow and ultimately die after weeks.

This will require you to replace your new sod and pull out the old grass (slimy, decomposing mess)– so avoid doing this if you want to save yourself from such a nightmare.

Resurfacing Old Weeds

Laying sod over existing grass makes the grass die and decompose in such a short amount of time. However, you’ll find that some lawn weeds can be truly resilient. Some lawn weed varieties can thrive despite being covered, and they will most likely make an appearance throughout the new sod. So if you want to save yourself from tearing up your existing grass and weeds, ensure to pull up any visible weeds after laying the sod.

Remember, these pesky, stubborn weeds may damage your new sod.

The New Sod will be Unsightly

Placing new sod over your existing lawn may sound like the ultimate time-saver, but it won’t look as good as a properly laid sod. This is especially true if you’re only applying the sod in specific areas. Even if the sod manages to survive somehow, it will likely be taller than the rest of your lawn– giving it a rugged, uneven appearance.

What You Must do Instead of Laying Sod Over Existing Lawn

Now that we’ve clarified what problems to expect with laying sod over existing grass, let’s discuss what you need to do to ensure sod is laid correctly. Following these expert-backed steps will help your new sod grow and flourish. Consider it a fool-proof way to revive your lawn’s pristine appearance!

1. Remove the Existing Grass

The first step in ensuring that your new sod establishes a healthy root system is to remove your old lawn before laying new sod properly. Your turf will be more durable, require less maintenance, and look better with a healthy and robust root system. If the old grass is thin enough, you may be able to remove it with a rototiller and rake. You'll replace and rake up any debris left behind by grass and its roots until you've completed the area.

You may wish to rent a sod cutter if the old grass is thicker or you're replacing a large section of lawn. With this tool, you can easily handle the large volume of debris by plucking the old grass up into strips.

To keep your new sod level with the rest of the lawn, remove about an inch of the old soil.

2. Prep your Soil

To loosen the remaining soil and break solid chunks; till the ground. The roots of the sod will be easier to grow in loose soil. Rake the soil to smooth out the surface and make your sod look flat with no uneven parts.

For additional nutrients, apply a thin layer of topsoil to the ground. Finally, gently water the soil to moisten it before putting your sod in.

3. Lay Down your Sod

Starting at the edge of your existing grass, spread your sod in sections onto the prepared soil. For optimal water retention, lay the sod horizontally on the slope if you have a sloping lawn. Make sure the strip of sod is completely covered in soil, then lay the subsequent section flush against the first, with no gaps between them.

Continue until you've covered the entire section of ground, then cut any excess sod using a sharp tool to ensure there are no overlapping sections.

4. What to do After You’ve Laid the Sod

For two to six weeks, water the newly laid sod a couple of times a day (or until the sod takes root). For up to four weeks after laying the sod, avoid walking on it or using it regularly. This will protect the newly formed roots and help them properly attach themselves to the soil.

Conclusion

A beautiful, lush lawn is truly a sight to behold. So once you’re dealing with discolored lawn or dying turfgrass, you may want to consider replacing it with new sod. When it comes to sodding your lawn, you should try to do it right and avoid cutting corners. Avoid shortcuts like laying sod over existing grass– this may only cost you more energy, time, and money. Please don’t do it!

Instead, remove the existing grass before sod application to ensure the new grass will grow in ideal conditions.

About the author 

Ken Wilson

Long time career in the home services industry from remodeling to patio construction. Currently residing to in SWFL and active contributor to multiple home & garden publications.