The relationships among convective planetary boundary layer (PBL) properties and land surface energy balance are explored using data from the Atmospheric Radiation Measurement Cloud and Radiation Test Bed in the Southern Great Plains (ARM-SGP). Previous attempts to infer surface fluxes from observations of the PBL have been constrained by difficulties in accurately estimating and parameterizing the conservation equation, and have been limited to multi-day averages or small samples of daily case studies. Using radiosonde and surface flux data for June, July, and August of 1997, 1999, and 2001, the conservation approach is applied to 132 sets of daily observations. Results highlight the limitations of using this method on daily time scales. A statistical investigation of relationships among PBL and land surface properties that are not explicitly included in conservation methods indicates that atmospheric stability in the layer of PBL growth is the most influential variable controlling PBL development. Significant relationships between PBL height and soil moisture, 2m-potential temperature, and 2m-specific humidity are also identified through this analysis, and are exploited using a statistical technique to predict and explain PBL growth from observations of stability and soil water content. Using this approach, it is possible to use limited observations of the PBL to estimate soil moisture, and by extension, land surface energy balance on daily timescales without the need for detailed land surface parameterizations.