Put some weed killer on block 3 week ago and cleaned it a week later when weeds had died.Lady rang yesterday and said edge of her lawn has died.Has the weed killer took 3 weeks to be absorbed into the ground and into the lawn?I stayed a foot away from grass,it wasn`t windy and lookily for me the custy is ok about it,she has scratched it out and put seed and lawn food down.Do you think it was me and it would take 3 weeks to travel through the ground,i thought the grass would of died with the weeds within a week if it was me.lesson learned.Dan