The seeds accomplish gaseous changes, which interfere in its physiologic processes, that characterize the hidration and drying process until the hygroscopic balance with the environment had been established. The understanding of the sense and of the time of those changes had been hindered by the absence of appropriate technique to estimate the hydric potential of the seeds; for this reason, the relationships between the water content of the seeds with the atmosphere had been foreseen starting from data, obtained experimentaly, of water content of the seeds submitted to well-known atmospheres. Thus, the alternative of esteeming the total water potential of the seeds would allow the necessary simplification to the understanding of the physical processes involved in its changes of water with the environment. Starting from data of the total water potential in the atmosphere and the water content of the seeds with well-known atmospheres, models were developed that allow to esteem the total water potential in seeds of corn, rice, soybean and common bean.