How do you remove thatch?

FAQ
Question: 

How do you remove thatch?

Answer: 

The most effective way to remove a thatch layer of ½ inch or greater is with a vertical mower or power rake.  Late summer (September) is the best time to dethatch lawns in Iowa.  Late summer dethatching gives the turfgrass several weeks of good growing weather in which to recover.  Dethatching machines are often available at rental agencies for individuals who prefer to do it themselves.  Dethatching can also be performed by professional lawn care companies.