When is the best time to apply pre-emergent?Updated a month ago

Cool Season Lawns(Kentucky Bluegrass, Tall Fescue, Rye):

The best time to apply pre-emergent on cool season lawns is very early in the season before the soil temperature consistently reaches 55 degrees(soil temperature map).  In the transition zone, the ideal time for the first application of 13-0-10 Guardian Pre-emergent Fertilizer should be applied between the end of January and Mid February.  Then another application of 13-0-10 can be applied April 1st.  or 6-7 weeks after the first application.

For northern areas, we suggest between March-April for the first application.  

Warm Season Lawns(Zoysia, Bermuda, St. Augustine, Centipede):

The best time to apply pre-emergent on warm season lawns is both in the fall and early spring.  Typically September-October of 0-0-7 pre-emergent if your lawn is on its way to going dormant.  Or 13-0-10 Guardian Pre-emergent Fertilizer if your lawn will be growing into December.

The following year, January-February 0-0-7 pre-emergent if the lawn is still dormant, or 13-0-10 if the lawn is actively growing.  6-7 weeks after, follow up with another application of 13-0-10 pre-emergent fertilizer for additional protection against weeds.

Pre-emergent is a herbicide that prevents seeds from germinating.  It will not kill any existing weeds or grasses.  It is highly effective preventing undesirable weeds from germinating as long as it is applied before germination.  

For accurate soil temperatures, please visit the Soil Temperature Map