Switchgrass is widely considered to be a likely crop to grow as a feedstock as the cellulosic bioenergy industry takes shape. It is a native, drought-tolerant, perennial grass with high yield potential on a wide range of soil conditions. Switchgrass is reputed to have high efficiency in converting fertilizer nutrients to harvestable biomass and low nutrient removal rates; however, there are very little data available on switchgrass nutrient use and fertilizer needs to substantiate that. Basic information is therefore needed on dry matter (biomass) accumulation and macronutrient uptake patterns during the growing season and their post-frost losses to construct useful nutrient balances.