There is provided an apparatus for surface treatment and collection of undesirable debris of a defined nature from lawns.During a cutting operation rotating blades ripe surface material up onto a filtering screen and along this further to a collecting box so that only stones and debris of e.g. at least 1 cm enter the box whereas smaller particles / soil escape through the filter screen and are thereby returned to the lawn surface, which significantly increases the nutrient level in the upper layers of the lawn.