Abstract: A low-temperature grain drying/aeration system includes a controller having an initialization circuit which is programmed on the basis of long term computer simulation of the low-temperature drying process to respond to inputs representing initial conditions such as harvest date, harvest moisture and air flow rate, and control a dry down indicator to indicate the probability of drying success and the time of completion of the drying. The controller responds to control outputs provided by the initialization circuit to provide humidistatic control of fan and heater operation during the drying operation, and to permit heater operation only when supplemental heat is desirable. At the end of the normal drying season, the controller automatically transfers operation from the drying mode to an aeration mode to provide periodic ventilation of the stored grain, and effects shut down of the system when conditioning of the grain is completed.