Scalped lawns occur when we cut a lawn too low, thus exposing the brown thatch layer which resides underneath the upper green leaf material of the lawn. Well that’s the essence of what a scalped lawn entails, but the matter is much more in depth as to what is really going on and why scalping has happened to a lawn during lawn mowing, as it’s rarely a case that we cut the lawn too short, though this can be an obvious cause.
And if we did cut our lawns too short, then it’s a simple case of raising our mowing heights to stop the problem from occurring again in the future.
However, what’s really happening in the case of scalped lawns is that we have cut the lawn too short in direct relation to the present height of the lawn prior to lawn mowing. This is why we could mow two similar neighbouring Bermudagrass lawns at say one inch, and one lawn will come up as a perfect flat carpet of lush green turf, while the neighboring lawn will be brown all over, scalped, ugly, and may be severely damaged due to sunburn if the mowing was done on a hot day, and may even die in places.
In this case, the perfect green finish to one lawn was because it was regularly mowed in direct relation to the growth rates of the season it was in, and so only a small amount of green leaf was removed, leaving the lawn lovely and green and trimmed perfectly.
Whereas the neighboring lawn was left a lot longer between cuts and became overgrown, and when it became overgrown the brown thatch layer increased in height, and the crowns of the lawn were also raised. Then when we mowed the lawn we cut right back into that raised brown thatch layer, leaving an ugly brown appearance. If we also cut into raised crowns in the lawn, then those parts of the lawn will die off and will need to be grown over again from the surrounding lawn area in order to repair itself.
Increased Thatch Layer
The same process is at work when our lawns naturally become heavily thatched over time, which is very common for warm season grasses being grown in full sun conditions. And when our lawns become heavily thatched they will be cut back into the brown thatch at every single mowing.
To stop this scalping of our lawns into the heavily thatched layer of the sod, we may naturally believe that the cure here would be to increase the lawn mowing heights. After all, if we increase lawn mowing heights then we wouldn’t be cutting into the thatch layer anymore, and the grass will be green after mowing again… and this is true… to an extent.
The problem here is that this is a temporary solution which will in fact make the thatch problem much worse over time. All we’re really doing is leaving the thatch layer in peace, to stay there undisturbed by us, and so what will be the end result of this? Well of course the thatch layer will only keep increasing in thickness. making the problem much worse over time. We may have solved our issue for right now, but next Summer we’ll find a much worse problem to deal with.
It’s a false paradigm isn’t it.
The truth of the matter is that we have a thatch problem in our lawn, which will need to be addressed at some stage. And if we don’t address this problem, it will only worsen and worsen.
Scalping Lawns For Benefit
We can scalp our lawns purposefully for the benefit of our lawns.
We would do this as a method to control thatch buildup and to remove thatch from our lawns, and we would do this lawn scalping with careful planning.
Spring is the best time of year to tackle a thatched up lawn with lawn mowing, the weather is still mild enough so as not to cause any heat stress to the lawn, which may otherwise damage the turf. Then as the weather warms up and the growing season for lawns is upon us, the lawn will continue to repair back to full health with speed.
We could also de-thatch with lawn mowing once the heat of Summer is over, though the lawn will have less time to repair as Winter approaches and the lawn begins to slow its growth rates. With this in mind, we should always aim for Spring for de-thatching lawns with lawn mowing, which in essense is the same as scalping, though this time it’s done on purpose.
A Spring cut back of lawns can be very beneficial to Saint Augustine grasses which will naturally increase their thatch layer as the years pass by, and unlike other lawn varieties Saint Augustine does have the natural inclination to grow a very thick thatch layer that can become a real problem if left alone.
There’s no need to beat the lawn to pieces in this process, though we don’t need to be overtly gentle either, but finding the right balance to remove the thatch we want removed within a reasonable space of time before Summer arrives.
In this process we would lower the lawn mowing height by a notch or two for at least a couple of cuts, until the lawn is no longer appearing to be brown after mowing at this new height. Then we may look at reducing the mowing height by another notch for a couple of more cuts. We must each take individual care here to ensure that our own lawns are coping well with this cut back in thatch, and not to take things to an extreme, especially if we have Saint Augustine grass, which needs a moderate thatch layer to stay alive.
Once we’ve determined that we’ve safely removed as much thatch as we’re comfortable with for our own lawns, because each lawn is different, then we can stop reducing mowing heights, and instead increase lawn mowing heights.
However this new increased lawn mowing height should still be lower than the original lawn mowing height. Because of the reduced amount of thatch in the lawn we should now safely be able to keep our lawns cut lower than before so as to keep thatch under control for some time to come. Until next we must cut back our lawns to remove thatch again.