While it may seem obvious that covering the grass with dirt could have negative effects, there are several applications where a thin soil layer will help improve your turf. Sometimes, temporarily covering the grass with a pile of dirt while landscaping happens, and of course, after bad storms, sometimes the soil is moved by erosion and will form a layer of soil on our turf.
Each of these examples of soil covering grass can have different effects on your turf.
Finding out if the grass will die if covered by soil can be a little more complicated as turf type, age of lawn, and amount of soil atop plants may result in very dead grass or fungal diseases. Other times grass seed and quickly dividing stolons may p[ush through and benefit from the rich soil added to the lawn.
To find out what may happen to your lawn if you put soil over grass, read the article below.
Will Covering Turf with Soil Kill My Lawn?
Covering turf with soil will not immediately kill a lawn, but a thicker soil layer placed over any plant for an extended period of time can attribute to poor drainage, which will lead to root suffocation and other life-threatening conditions.
Soil on turf can also be used effectively to aid aesthetic appeal by removing low dips and gullies, but the process needs to be done gradually. Grass seeds can also benefit from a thin layer of a decent soil mix that will protect them from wind and pests and allow them to develop thick roots faster.
If you want to kill sections of turf with soil, that is possible as well and can be effective if that area has become discolored or weaker than the rest of the turf. Covering these areas with a soil layer thicker than 3 inches can kill the plants underneath over the course of several weeks.
Increasing the soil depth may lessen the time it takes to kill the turf, but adding more inches of dirt than is needed may make it harder to even it out later.
Can I Pile Soil on Grass While Landscaping?
It takes time with soil application on grass for there to be any negative effects, and simply placing a layer of dirt on your turf while you dig a hole or fix an irrigation pipe will not have any lasting effects.
Make sure not to damage the grass with a shovel and to remove all but the thinnest layer of soil when you are done landscaping. Often it makes more sense to lay down cardboard or a tarp to make clean-up easier, but this small amount of topsoil over grass will not kill your turf.
When landscaping, if you aren’t going to use all the soil you displace, this can be a great time to use the excess dirt to level out low spots in your lawn. An uneven lawn can be harder to mow and may result in scalping, which will kill your turf immediately.
An annual or bi-annual topsoil application in lower areas can fix your lawn to contribute to easier proper lawn care practices and a stunning well-kept lawn.
Can Grass Grow through Dirt Piles?
Putting dirt over grass blocks the sunlight and, in most cases, puts the plant in overdrive. Some grass and weeds can push through the dirt pile and find sunlight again and perhaps grow stronger because of it.
Other grasses will not have the strength or propagation techniques needed to survive a dirt pile and will succumb to root suffocation and lack of UV light. If the goal of the pile is to kill the grass, make sure to place it and not disturb it, as grass seeds put off in a last ditch to survive may work up to the surface and sprout anew.
Effects of Covering Grass with Dirt
The damage done to the turf by covering your lawn with dirt varies depending on several factors. Understanding that, in most cases, covering your grass with anything will weaken it, it becomes extra important to observe the effects of even a thin layer of soil placed on the lawn.
If you are trying to improve your lawn with soil, work on the grass with dirt and not leave lasting damage, or you want to use dirt as a way to get rid of a stubborn patch of plants, then check out the chart below for the effects of various layers of dirt on turf.
|Amount of Dirt
|No negative effect on the grass and fertile topsoil can provide numerous benefits
|Grass gets some nutrients, and exposed roots can be covered as well as helping to speed up the breakdown of thatch and other plant debris
|A thin layer of nutrient-rich soil can be placed over the lawn as a top dressing, and soil with compost will increase beneficial organisms in the earth
|Soil rich in nutrients will give spring grass a boost, and adding inches of dirt gradually can reduce soil compaction and improve drainage
|Adding 3 or more inches of dirt on a lawn can cause negative effects, and although a stubborn plant may grow through it, there will be a weakening of the roots and the potential for fungal disease and other maladies
|A thick layer of dirt left over the grass for too long will lead to the death of the plant and most likely will create an environment for weeds and other undesirable invasive species to thrive
|5-inch-thick dirt layers or a pile will lead to the death of the grass in the surrounding area and can be used as a plant eradication method prior to a big landscaping or construction project in the lawn
|After the pile has killed the grass, the dirt can be spread to a thinner lawyer and compacted, making it a better base to build on than dirt with root gaps and vegetation that can still break down and move, leading to shifting of structures and expensive repairs
How Quickly Will Covered Grass Die?
In general, it will take several weeks for the grass to fully die under a pile of dirt. While the blades may be crushed by the weight of the soil, slow and full death comes to the roots through suffocation and a lack of energy to synthesize nutrients. Resilient plants may last for a month or longer, but eventually, all plants that are unable to divide out of the dirt zone will die.
You can speed up the speed by which plants die under dirt by using a natural or commercial herbicide prior to covering the plants with dirt. This can be effective when changing turf type or trying to eliminate a noxious weed. Compacting the dirt after dropping it will also force any air pockets around the roots of the undesirable plants to close, speeding up the suffocation of the plants.
How to Prevent Grass Dying When Covered with Dirt?
The simplest way to prevent grass from being killed when covered with soil is to use the right soil type and add it in thin layers, gradually over a long time. This will add nutrients to your soil, allow you to control weed and pest outbreaks that may occur from contaminated soil sources, and even out any erosion-prone or scalable sections of turf.
Evenly applying soil in a thin layer can be difficult and additional techniques can be used to make sure you don’t pile any dirt too high and risk killing the grass.
A rake and broom can help you when too much dirt is added or if you are spreading the soil out from a central point. A large pile dumped in the lawn will kill the grass underneath but using a shovel and wheelbarrow to distribute it can help protect the turf underground.
Once the pile has been reduced to just above the current grass level, you will want to switch to your rake.
A sturdy rake is needed to push and pull the dirt until all the little mounds are knocked down and spread out. As you go through, pull any high areas down and push them until the dirt is more or less level. Even with the best raking, you will still see clump and unsoiled areas.
Using a push broom finish leveling out the soil to achieve the most even and thin layer possible. If you want to leave layers of soil up to 2 inches thick in the deepest gullies, you can but make sure to reseed as well to increase the likelihood that the grass will grow thick and even.