<H1>PPT Slide</H1> <P><UL> Turfgrass roots below the herbicide layer</UL></P> <P><UL> Herbicide layer</UL></P> <P><UL> Weed seeds germinate and are controlled as they come in contact with the herbicide.</UL></P> <P><UL> Preemergence herbicides do not prevent weed seeds from germinating.</UL></P> <P></P> <P>