Thatch

What is thatch?  Thatch is living and dead plant material in a lawn that has built up on top of the soil that is slow to decompose.  Hybrid Bermudagrass and Zoysia have more problems with thatch than other types of grass.  A certain amount of thatch is acceptable - up to a half inch can regulate the temperature of the soil, retain moisture and provide decomposing plant material for insects, earthworms and microbes.  More than a half inch of thatch can be a problem, because it prevents water and pesticides from reaching the soil when applied.

How do I get rid of thatch?  Timing is important - for warm-season grasses, this should be done after the grass has greened up or later, when it is actively growing.  Around here, that is late April or early May.  Don't apply in very hot or dry weather.  If you have a small area, you can use a de-thatching rake - it's similar to a garden rake, but it has curved tines which pull the thatch layer away from the soil.  If you have a large area, you will need to use some sort of powered de-thatching equipment.  It has vertical blades that cut through the thatch layer, making it easier to remove with a rake.  Once the thatch is removed, you need to water your lawn to help it recover - in addition, a week later, a fertilizer application of one pound of nitrogen per 1000 square feet should be applied to your lawn and watered in thoroughly.

How do I prevent thatch?  Good lawn maintenance is key.   Mowing at the proper height for your type of grass is one way.  Also don't over-fertilize or over-water.  For more information , please see:  HGIC 2360 Controlling Thatch in Lawns.