Timing is key when dealing with pre-emergents. Too early and the barrier wears down and weeds start to grow. Too late, and the germination process has already happened. Preventing weeds in your lawn is like playing a strategy game. You always need to be a few steps ahead. To get the timing right, you need to know exactly how the pre-emergents work. Listen as Garrett explains the process. If you have any questions, let us know!