The Minimum Soil Depth for Growing Grass Over Rubble

You’ve moved into a newly-constructed home, only to find that your property is covered in builder’s rubble. Obviously, turning that raw earth into a healthy, thriving lawn is going to be among your first priorities, so let’s look at the best way to achieve that goal!

What is Rubble?

Rubble is a mixture of stones, old concrete, rough soil, clay, and sand that has been left behind by the building process. Digging down 4 to 8 feet or so to create a basement foundation is going to generate tons of such material, which either has to be hauled off the site, or spread out and graded around the property.

Rubble is also the debris leftover from a building site that was torn down and demolished, these sites are often quite messy and the rubble size could be much larger. 

New construction rubble is often gravel and crushed stone, you may find some other material chunks around as well. But for the most part your new construction home should have been cleaned up prior to you moving in.

rubble types

Can You Grow Grass Over Rubble?

It can be challenging to grow grass on rubble, it will depend on how thick the rubble is.

Getting rid of the large rubble is a big and expensive job, and it may be contributing valuable subsoil to your property. For instance, it may be used to build up a septic tile bed, or grade a slope away from the foundations to ensure that water runs off rather than ending up in your basement. However, because on its own rubble will not foster the growth of a lush, healthy lawn, you will need to add a thick layer of topsoil to create a good growing medium for grass.

Read our related post “Minimum Soil Depth for Growing Grass Over Concrete” here. 

What Should You Consider Before Growing Grass Over Rubble?

Before making your plans to proceed with growing grass over rubble, you need to first determine exactly what’s in the ground. If your builder has left behind chunks of wood in the subsoil, for instance, those are going to rot down, leaving you with sinkholes across your lawn in a few years. This can also happen if large chunks of stone or concrete rubble have left empty pockets underground, that over time will open up when the ground settles.

You should dig down 3 feet in a few spots across your lawn, just to see what the composition of the rubble actually is. If you find a lot of undesirables such as those listed above, you may need to do some major excavation and rubble removal before proceeding.

What’s the Minimum Soil Depth for Growing Grass Over Rubble?

The more space that grass roots have to spread, the better your lawn is going to be. This means anything between 6 to 12 inches (15 to 30 cm) soil depth across your entire lawn. While grass growing over a thin layer of topsoil may start out strong, once the roots hit the rubble layer, they’re going to be unable to grow much further, and the quality of your lawn will deteriorate and need replacing. Save yourself the time, money, and effort and do it right the first time!

Should You Lay Other Materials Before You Add Your Soil?

Once you’ve levelled out the rubble layer, you should have a decent surface for your topsoil layer. Don’t add a fabric barrier or anything else that could interfere with root development. Just make sure that the rubble isn’t totally packed down, as you will want good drainage to prevent the topsoil from getting waterlogged and drowning roots. Loosen the surface up before adding the topsoil.

Is it Better to Lay Sods or Plant Grass Seed When Growing Grass Over Rubble?

Your choice of sod or seed for starting a lawn over rubble depends on your budget, size of your yard, and time frame.

Sod is more expensive, but it results in a finished lawn faster than spreading seed. Within a month a sodded lawn will be able to withstand foot traffic. On the other hand, you can expect a seeded lawn to take a full growing season to really mature to that point.

“When I moved into my newly constructed home there was minor rubble all around as the entire neighborhood was new. With added soil, we had sods placed around the house and we maintained a regular watering schedule to keep the grass alive and growing. Within a 1-2 months the sods began to grow deeper roots into the rubble layer. 

I personally think sods are a better option for growing over rubble layer, its faster and an easier option. When I was a new home construction Realtor all our homes were built and polished off with a fresh sod lawn. This looked great and ensured the new owner a new thick looking lawn.” – Jamie Penney (Owner of TheBackyardPros)

Tips for Growing Grass Over Rubble

1. Use Nutrient Rich Soil

Use the best soil that you can afford for growing grass over a rubble base. Don’t just buy loads of straight topsoil, as the quality varies from one supplier to the next. For instance, the people we bought our house from claimed to have trucked in many loads of “topsoil” to cover the rubble when they built it ten years previously. It’s almost pure sand.

Instead, try a mixture of good, black topsoil blended with well-rotted compost (mushroom compost is available in bulk in many parts of the country). This will ensure a nutrient-rich growing medium that will retain moisture and encourage strong growth.

2. Avoid Heavy Traffic Early On

A new lawn needs to be given a chance to get established before it gets heavy foot traffic. Even a sod lawn will take a few weeks to start growing into the soil before it can withstand that stress, and a seeded lawn should be off-limits for a minimum of two to three months. You may need to put up temporary fencing to keep animals and children out of the area. 

3. Set Up a Water Schedule

Regular watering is essential for establishing a new lawn. If the weather doesn’t cooperate and there’s no rain to do it for you, you are going to have to water at least once a day to keep the soil moist, especially for a seeded lawn, for the first three or four weeks. Set up sprinklers to keep in place so that you don’t even have to walk on the new lawn for watering purposes.

4. Hold Off on Mowing

A new lawn can be damaged by mowing too soon. Not only will the new growth be crushed easily by walking or riding across it, but the baby blades of grass will not be able withstand the stress of being cut. Wait until the grass is at least three inches (7.5 cm) tall before its first mow, and set the blades high to cut off a minimal amount.

Once you’ve mown the new lawn two or three times, the root system should be developed enough to withstand some foot traffic.

5. Make it a Condition When Buying a New Home

This is another tip from Jamie, I was a realtor and I know the importance of move-in ready for new construction. After waiting 6-12 months for your home to be built you do not want a lot of work to do when you move in. Lawns are a lot of work!

Make it a condition for the builder to properly sod the lawn for you. This was very common when I worked in the field in Halifax. Depending on the current market you may be able to get it without adding on extra costs, sometimes they might add it on to the selling price. But hey, you don’t know unless you try!

Tell your Realtor to make sure its a condition on your offer.

Final Thoughts

When moving into a newly-built house, most owners are eager to turn the bare ground into a green lawn. Take the time to prepare the ground properly, and you’ll have a lush carpet of grass to enjoy for years!

With proper soil levels and preparation you can have the nicest looking lawn in the neighborhood. Good luck!

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