There are times when a lawn needs more than watering, mowing and feeding.
Time to watch out for Thatch.

Thatch is the layer that is between the active runners & leafblades and the soil. It is a build up of old grass roots, runners and rhizomes.

A bit of thatch is actually good for grass since it:
• Keeps soil cool
• Slows water loss
• Insulates from temperature fluctuation
• Improves tolerance to foot traffic
• Acts as a weed barrier

While thatch is natural and beneficial, it becomes a real problem when it increases to excessive amounts.

Excessive watering and nitrogen use can cause high thatch levels.

About 2cm of thatch is normal and healthy, more than 2cm can lead to problems.
If the thatch layer gets too thick, water and air have trouble getting to roots and disease can take over.

Dethatching is stressful for your lawn so the optimal time is when your lawn is growing its fastest. For warm season grasses such as Buffalo, Kikuyu and Couch, this is spring.

Dependent on the variety of lawn you have a few options…

Aerating or coring is when you pull plugs out of the soil and open up the ground. This had a double action of removing thatch AND loosens compacted soil and allows air and water to reach the roots. If you have heavy thatch you may need to use a dethatcher or low mow preferably for a better result.

How Often Should You Aerate?
If you have high-traffic areas and heavy thatch, you might want to aerate every year or 2. If your lawn looks great, you can cut back to every 3-5 years.

Dethatcher or scarifyer
If you have a small patch of lawn and don’t mind a little exercise, you can use a dethatching rake. As you pull it through the grass, it lifts up and moves the thatch. For a larger area may prefer a machine, which can be rented. It combs your grass and kicks out a large amount of material, which you’ll have to rake off afterwards. This method removes the most amount of thatch. This method in not recommended for buffalo.

Mower Method
The simplest and easiest method is to mow the lawn short once every spring. Simply, Make sure you have sharp blades, drop the mower to a low height and take your lawn down low. Drop the mower down to a level where you actually see a small amount of dirt showing through the runners crossing the ground

Dethatching a Buffalo Lawn
Over time, Buffalo grass runners will grow over the top of each other, eventually smothering the runners and leaf underneath. Left for many years a thick layer develops which causes a number of problems.
Because buffalo doesn’t have underground runners to grow back, you need to be more cautious in how low you go. It is best to use the low mow method to control how much thatch you take out. Make sure there are still lots of runners crisscrossing the ground when you are finished.
For Couch and Kikuyu you can use any of the three methods. Couch will need dethatching every year, whilst buffalo and kikuyu every two – three years.

After dethatching is the best time to fertilise and TOP DRESS your lawn for the best results.

What do I do if it is an older lawn and the thatch is really bad?
If you have not mown the lawn short for many years, and the thatch level is very high, you may need to lower the height of the lawn gradually over a month or so. Allowing your lawn to recover in-between.

Top Dressing
This is great for all lawns.
Provided the level of the lawn is not already too high, this is a great way to rejuvenate your Buffalo lawn.
Use a sandy loam top dressing mix from your local supplier. Simply spread the mix over the top of the lawn.
Spread the mix over the lawn with a shovel, then rake it out so some of the leaves are still showing.

It is recommended to top dress every 3 years provided the level of the lawn is not too high above paths or drainage points.

For more lawn information, just head to the Turf Farm website






About The Author

In the Garden is an exciting new local South Australian TV program on Channel 9 this Summer & next Autumn showcasing the best ‘green’ stories this state has to tell. Check out the latest in garden trends, new plants and top tips to keep those gardens blooming.