According to the glider pilot, after a local flight, he returned to the airport for landing. During his approach to the grassy area adjacent to runway 23, the pilot used an excessive amount of spoiler to descend, and landed short of the runway. The glider's right wing struck a taxiway sign and light, resulting in substantial damage. The pilot reported no mechanical anomalies with the glider, and the winds were calm at the time of the accident.