Imbibition temperatures above 25°C reduced the percentage, rate and uniformity of germination in spinach seeds ( Spinacia oleracea). This reduction was significantly less marked in seeds that had previously been either leached or removed from their enclosing pericarp. The optimum temperature for leaching was between 10 and 20°C. The duration of leaching required to improve germination at 30°C decreased as the temperature of leaching was raised. Water soluble inhibitors of germination were detected in leachates both from the pericarp and from the de-coated seed. Leaching for longer than 6 h failed to increase the levels of inhibitors removed from the seeds, whereas the longer leaching treatments given at less than 20°C did result in further improvements in germination at high temperature.