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Wednesday, March 20, 2013

Thatch management

Thatch is a layer of living and dead organic matter that occurs between the turf and the soil surface. The primary component of thatch is turfgrass stems and roots. It accumulates as these plant parts buildup faster than they breakdown. Thatch problems are due to a combination of biological, cultural, and environmental factors. Cultural practices can have a big impact on thatch. For example, heavy nitrogen fertilizer applications or over watering frequently contribute to thatch, because they cause the lawn to grow too fast. Excessive thatch (over 1/2 inch thick) creates a favorable environment for pests and disease, an unfavorable growing environment for grass roots, and can interfere with water infiltration into the soil. You've probably walked on turf that feels "spongy." That's a sign that there is a real problem with excessive thatch buildup. One of the main reasons we frequently topdress with sand is to slow down the formation of thatch and keep the turf surface smooth and firm. If thatch is not controlled on a putting green, the surface will get very bumpy from foot traffic because it's too soft. Add a day or two of rain and a full field of golfers, and the putting surface is a gooey mess. One of the tools we use to remove thatch is a a verticutter. Circular blades with carbide tips mounted to a shaft spin around and cut into the top layer. Depending how deep below the turf surface the blades are set will determine how much thatch is removed. On a green we typically set the blades 1/8" deep. On a tee, we can set the blades 1/4 to 1/2" below the surface and really pull out some thatch.
The machine above is a verticutter that mounts to a tractor to do tees and approaches. This would be way to aggressive to use on a green, but works great on areas with longer grass where surface disruption is acceptable. We're don't  putt on a tee so it doesn't matter if we tear up the surface a bit. We just need it to be firm so it holds up to traffic. The photo below is the type of verticutter units used on greens. The blades are thinner and won't cut as deep into the surface as the tractor mount unit. The greens verticutters get mounted to a triplex greens mower to do the job.
Blowing off the mess
After verticutting is done, thatch is blown off the tee and it's ready for sand.



During times of the year when rounds of golf are low, we can really lay the sand on thick and work it in over several days. In the playing season there are too many golfers and this rate of sand would be unacceptable. Between aeration, verticutting, and sanding, we are able to keep the thatch level at an acceptable level so the turf stays smooth and firm and good for golf.

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