Doff Lawn Weedkiller has been specially formulated to kill common lawn weeds without damaging the grass. Its active ingredients Mecoprop-P and Dicamba, target broad leafed weeds. Best used when the weeds are growing, from late spring until early autumn. It shouldn't be used on new lawns that are less than 6 months old. 1 litre treats up to 50m of lawn. Once the weedkiller has dried the area is safe for children and pets.