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Mega-Thatch September 2, 2016 By Bob Vavrek, regional director, Central Region

Under the right conditions, years of neglect can cause a mega-thatch accumulation. Don't expect immediate results when you begin chipping away at the problem.

Many courses choose to ignore fairway thatch problems because management options such as core aeration, aggressive vertical mowing and sand topdressing are expensive, time-consuming, and labor-intensive operations that cause temporary disruption to the playing surface. Every experienced turf manager knows that excessive thatch accumulation is a potential problem, but dealing with 30 acres of spongy turf is often put on the back burner until something bad happens. After all, thatch is below the playing surface and as the saying goes, “out of sight, out of mind.”

A recently-visited course in the Central Region illustrates how problems can develop. The stage was set when more than 30 acres of creeping bentgrass fairways were established at a resort course in a northern location.  Relatively little play and cart traffic was anticipated until the facility established a reputation that would draw golfers away from urban areas. Ample nitrogen was applied during grow-in to establish turf quickly in the short growing season. The assumption that resort golfers like green, lush turf meant there was little incentive to limit nitrogen inputs once the course opened for play.

Thatch accumulation was off and running from day one. After several seasons of limited play, standard maintenance practices such as core aeration were suspended due to inconsistent cash flow and the damage caused to aeration equipment trying to pull cores from the rocky native soil. Maintenance inputs continued to decrease for a few more seasons prior to a change in ownership.

It should come as no surprise that the new owner inherited about 2 inches of dense fairway thatch. Not just thatch, but mega-thatch; the kind homesteaders used to build their little home on the prairie. Hidden beneath the playing surface, it remained unnoticed until an extended period of hot, humid weather caused the thatch to swell and become puffy. Witnesses say the turf scalping that followed was quite impressive.

Now that the problem had been discovered, what should be done to address it? Core aeration caused too much damage to equipment and aggressive sand topdressing was not an option due to the cost of equipment and materials. A prairie fire to burn the thatch is an interesting thought at this point, but obviously out of the question.

The course decided to purchase a heavy-duty vertical mower and sweeper to physically remove thatch from the turf several times a season. Deep vertical mowing will eventually improve the situation if the amount of thatch removed exceeds the amount of thatch produced each season. Unfortunately, there is no quick fix for a problem that took many years to develop.

Perhaps the most useful take-home message is to avoid letting thatch get out of control in the first place. You don't need expensive lab tests to monitor fairway thatch, just a knife and a ruler. Address drainage problems because wet areas will always develop thatch problems first. Aerating with hollow tines and working the soil plugs back into the turf is a very effective way to manage thatch because it encourages the natural processes of organic matter decay.

Remember, the longer you wait to deal with a thatch problem, the longer it takes to achieve results.


Central Region Agronomists:

Bob Vavrek, regional director –

John Daniels, agronomist –

Zach Nicoludis, agronomist –

Information on the USGA’s Course Consulting Service 

Contact the Green Section Staff

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