The pilot reported that this flight was conducted as part of phase 1 flight testing of the newly constructed experimental amateur-built airplane. The pilot stated that he had watched a video from the airplane kit manufacturer on “factory takeoff,” which suggested keeping the control stick slightly aft of neutral and applying partial power. During the accident takeoff, he tried the method described by the video and when the airplane lifted off, it was too slow. About 5ft above ground level, the airplane stalled, and the left wing dropped. The airplane impacted to the left of the runway and continued into a ditch and an area of brush, resulting in substantial damage to the left wing. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.