Nutrient additions to streams are of concern in the Southeastern USA and more information is needed as to the impact of those additions on stream periphyton assemblages and growth. In streams, autotrophs such as algae control the transfer of atmospheric carbon to higher trophic levels. This primary production (conversion of carbon dioxide to organic compounds) and detrital decomposition are influenced by nutrient availability. In streams, periphyton (primarily algae attached to aquatic substrates) response to nutrient (N & P) additions is variable. Limitation and extent of periphyton growth by N & P were tested using periphytometers carrying two types of passive nutrient diffusion substrates, a nutrient solution bottle with a glass fiber filter and a nutrient-infused agar vial with porcelain disk. Six sites on two rural Piedmont streams with watershed land use characterized as either forested, pasture, or hayfield were selected. Physicochemical parameters including radiation, temperature, DO, and ambient nutrients were also tested. In one-out-of six sites, using the nutrient solution with a glass fiber filter for colonization method and in two-out-of six sites, using the nutrient-infused agar with porcelain disk for colonization method, evidence showed that periphyton growth was inhibited by added nitrate.