Within a month or so we will start applying the fall pre-emerge herbicides. These herbicides do one thing, kill seeds. The trick is all about timing. We need to apply them before the seed starts to germinate. The big question is when is the best time? The rule of thumb is from the first of September to the first of November. The kicker is that seeds don’t care what month it is. All they care about is moisture, the presents of soil, air and soil temperature. There are some that require a specific amount of sunlight. When the specific conditions are met, the seed will sprout.
The two products I prefer are Dimension for the grassy weeds and Gallery for the broadleaf weeds. And as always read and follow the label directions. The following link will help.