The pilot and a pilot-rated passenger were taking the airplane to the local airport in order to have an annual inspection completed on the airplane. During the landing roll on the grass runway (1,900 feet long by 120 feet wide), the landing gear encountered soft terrain. Subsequently, the nose landing gear collapsed, and the left wing contacted terrain. Examination of the airplane revealed the left wing was bent aft at the wing root. The pilot and passenger were not injured. The pilot stated that the airport owner told them someone had landed on the grass runway earlier that day so they decided the surface was adequate for landing.