Two morphological types of tubers of yellow nutsedge (Cyperus esculentus L.) were collected over a 2-year period and were sprouted in the laboratory. Tuber dormancy occurred during late summer and early fall. Sprouting was highest during the winter and spring. Mechanical disturbance of the nutsedge stand increased tuber sprouting. Available carbohydrates followed a pattern similar to sprouting; minimum levels were found during late summer. The 2 types of tubers appeared to be similar in respect to the characteristics studied.