Investigation of post-amendment biochar impact on low clay soil moisture provides agriculture professionals with much needed data. While laboratory testing is available, we propose inexpensive containers, tools and measuring devices to enable agriculture professionals to directly assess biochar impact on gravimetric water content, shrinkage, and release at point of soil rupture. Sandy loam, silty loam and loamy sand soils are amended (10%) with lignocellulosic (oak) and hemicellulosic (cardboard) biochars in cup, plug and roll experiments. Cups with oak and cardboard biochar addition produced 76.32% and 75.72% H2O retention respectively, compared to 67.75% (67.75 g H2O 100 g−1 H2O) for controls. Cardboard and oak biochar limited diametric shrinkage to 2.95% (1.29 mm) and 3.75% (1.65 mm) respectively; controls shrunk 6.96% (3.06 mm). Oak and cardboard biochar limited depth shrinkage to 2.95% (0.38 mm) and 2.99% (0.38 mm) respectively; control depth shrinkage is 3.64% (0.47 mm). In roll tests, cardboard and oak biochar treatment yielded 28.07% (1.37 g H2O), and 26.69% (1.3 g H2O) moisture at rupture, respectively, compared with 11.98% (0.58 g) for controls. Significant (p ≤ 0.001) differences in moisture retention, shrinkage and available moisture at rupture confirm biochar contributions to improved moisture performance. Physico-chemical analyses complemented experimental findings. We find study methods suit the needs of agricultural professionals to measure moisture while working with biochar to amend soils.