AbstractEstimation of plant root activities by the minirhizotron technique is a nondestructive approach for observing root responses to the soil environment, yet few such observations have been made. The purpose of this report is to compare methods for installing minirhizotron tubes in separate experiments located in two regions of the USA. Transparent plastic tubes were installed at acute angles of 0.8 and 1.2 rad to the surfaces of sandy loam (Typic Hapludult and Typic Hapludalf) soils located in Georgia and Michigan. Soil cores were removed from these low expansion‐contraction soils using Giddings hydraulic power samplers. Both ends of the minirhizotrons were stoppered and the aboveground portion of the tube surfaces were made opaque before inserting. The excellent soil to minirhizotron wall interfaces provided clear and high contrast root images that were observed and video recorded. These procedures provided information which indicate that short‐term drought results in root losses near the soil surface and large increases in deep root growth. Uninterrupted O2 stress substantially reduced growth of wheat (Triticum aestivum L.) roots throughout the rhizosphere.