The pilot reported that after landing the tailwheel equipped airplane on the turf airstrip, local residents advised him of soft spots in the runway surface due to recently melted snow. The pilot said that he walked the areas and taxied on the taxiway and turf runway without any issues. He taxied to the end of the runway and prepared for takeoff, which included choosing a takeoff path that appeared dryer. About 450 ft into the takeoff roll, the airplane encountered a soft spot on the runway which slowed the airplane, raised the tail, and the airplane “jerked” to one side. The left wing struck the ground and the airplane then nosed over. When asked if any mechanical problems with the airplane existed prior to the accident the pilot replied that there were none and that the airplane just sunk into the soft turf during the takeoff. The airplane incurred substantial damage to the engine mount, right wing, and right wing strut.