Seeds germinate when conditions are favorable and the seeds encounter appropriate environmental cues. The seeds of several species will not germinate immediately. They have their own characteristic set of germination requirements, often remaining dormant for several months. Seeds of many plants require stratification chilling the imbibed seeds for a period of time. The requirement for exposure to low temperatures for an extended period of time prevents the seeds from germinating in the fall or winter months in response to an unseasonably warm period (Fenner 1985; Salisbury & Ross 1985). Seeds germinating during a January thaw would almost certainly be killed when winter temperatures returned; dormant seeds are far less affected by extreme cold. Some previous work with MacIntosh apple seeds showed them to be good candidates for stratification experiments: they are readily available, easy to work with, classical in their need for stratification, and therefore well suited for use in the high school or introductory college biology laboratory.