Switchgrass was identified by the U.S. Department of Energy as a “model” bioenergy crop in 1991.   Since then a great deal of research has been performed for its use as a bioenergy feedstock.  Based on recent estimates from field trials, Tennessee is one of the few states in the U.S. where switchgrass can produce the greatest yields.  Switchgrass can be used as an alternative to coal in power plants or can be converted to cellulosic ethanol for transportation fuels.  While yield is important in feedstock production, the quality of the biomass is necessary to allow for optimal energy conversion and reduced economic costs. More information is therefore necessary to determine how the quality characteristics of switchgrass change over the growth period to identify best harvest management practices.  Switchgrass planted in 2006 was harvested every two weeks beginning in May 2011 and analyzed for moisture content, total C, total N, ash content, and total K, Na, Ca, Mg.  The effects of growth period on these quality characteristics will be discussed.