Thatch is a natural occurrence on every lawn. It has a reputation for damaging the lawn and leaving it looking terrible, yet thatch is an important component of any garden, providing a protective layer that limits the impact from extreme temperatures and excessive moisture levels.
However, you need to ensure that there is an appropriate amount of thatch. Too much or too little can cause a host of problems, which is where it got a poor reputation from! Thankfully, dealing with lawn thatch is easy enough, with some minor maintenance required to get it to the right levels for a healthier lawn.
What Causes Thatch to Develop?
Another misconception is that lawn thatch develops from old grass clippings. This isn’t true, with thatch developing as grass naturally grows. When grass grows it develops new roots, leaves, and stems.
As this happens, the older growth dies off and is destroyed by fungi, leaving behind just the right amount of thatch for a healthy lawn. However, the thatch often over accumulates due to improper lawn maintenance.
For instance, too much thatch develops when the grass grows faster than fungi kill it off, usually due to using too much fertiliser.
To get the right balance of thatch, the grass must grow at roughly the same rate as it dies, otherwise too much accumulates and causes all kinds of issues. For example, root damage occurs when thatch is too thick, while it may also cause root rot due to it holding lots of moisture.
How Can I Tell if there Too Much Thatch in a Lawn?
Identifying how much thatch is present is easy enough. If you walk over the lawn and it feels very soft and spongy underfoot, chances are you have too much thatch. If you look closely there should be a lot of brown material just below the grass.
Does the Type of Grass Impact Thatch Development?
There are certain grasses that impact how quickly thatch develops. For example, bentgrass is known to cause thatch to accumulate much faster than grasses like fescue, so bear this in mind if dealing with this type of grass.
How Do I Deal with Thatch in a Lawn?
The best way to deal with thatch is proper fertilisation. Don’t use too much to encourage fast and efficient growth during spring and summer, otherwise it will grow much faster than it dies off and quickly accumulates.
Soil compaction can also increase thatching, so it helps to aerate soil at the start of spring. You can do this with a lawn aerator or garden fork, pushing it into the lawn at regular intervals to improve airflow. This in turn encourages deeper root development, further reducing the rate of thatching.
Related: How to aerate the lawn
Another option is to add a lawn topdressing to the lawn. Topdressing products are available from most garden supply retailers and come with added ingredients like sand or natural soils. These encourage the thatch to die off faster, so can be used to get the right balance between growth and decomposition.
What About De-Thatching?
Using a scarifier or rake to de-thatch is a popular method for removing lawn thatch. However, this merely treats the symptom rather than the problem, as the growth and decomposing rate will still be off-balance so the thatch is only going to come back.
Instead, you need to ensure it’s properly fertilised and the grass grows at the same pace as the old growth dies off. Of course, if you are dealing with a lot of thatch then you can remove it by scarifying or de-thatching using appropriate tools.
Mechanical scarifiers are very efficient and will do the job much faster than using a rake or manual tool. Even then, these are only likely to remove around one third of thatch at best, so should only be used on top of the other methods mentioned above.
A Little Bit is Just Enough
While you may be tempted to remove all thatch, remember that it is good to keep a small layer to protect your lawn! It encourages healthier, more vibrant growth when left at the right level, so don’t make the mistake of removing as much of it as you can.