Magazine: Just Thatch
By Graden in Consultancy on 14th Jul 2008 6:00
“Thatch is that tightly intermingled layer of dead and living parts (roots, shoots, stems, stolons, leaf tissue, etc) that develops between the green vegetation and soil surface” Dr Martin Ferguson
Leaf clippings contribute very little to thatch buildup. Roots, rhizomes and stolons are major contributors to thatch as they have a high lignin concentration
and resist decomposition.
How much is too much?
A thatch layer of up to 13mm can be beneficial as it can improve wear tolerance and insulates the soil from extremes in air temperature. When thatch levels
accumulate beyond this the disadvantages far outweigh the advantages.
These problems will be exaggerated when excessive thatch layers are present.
The picture on the right shows a very severe thatch problem on a USGA constructed green. You can also see that by failing to fill the hollow core hole to the surface the space has started filling up with thatch. This worst case scenario means there is no root structure left and the vicious thatch cycle continues.
Thatch production is inevitable and is without doubt one of the most common problems encountered on golf courses and sports surfaces throughout the world. There are many different factors which contribute to excessive thatch accumulation. Some of these factors include grass species, climate, acidic conditions, poor aeration, high nitrogen nutritional levels and over weeding.
Problems caused by excessive thatch
- Reduction in air exchange
- Reduced water infiltration
- Poor seed germination
- Severe dry patch
- Inability to cope with drought and high temperatures
- Increased disease and insect problems
- Soft spongy playing surfaces
- Shallow rooting system
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 "The picture on the right shows a very severe thatch problem on a USGA constructed green")
and resist decomposition.
