The front edge of the lawn mower housing has an array of tines (4) facing and reaching downwards which comb the long grass into strands. The rear ends of the tines lead to the cutting circle (6) of the rotary blade (3), with the outer tines having rear extensions (11). The tines reach down to the bottom edge of the mower housing. Gaps (5) between the tines can be blocked by a shaped insert bar (7) with closure elements (10) that move vertically into the gaps when the mower is to be used on short cut grass. Scales on the bar and on the mounting (8) enable the user to set the bar height to best suit the length of grass to be cut.
