March 25, 2012 at 11:00 pm

Although it’s March and only a few days into spring 2012 is off to a fast start!  If you rely solely on the calendar to make applications you could be in for a big disappointment this year.  Crabgrass germinates when soil temperatures are around 60-62 degrees at 1-2 inches deep.  In a “normal” year this doesn’t happen in the Midwest until late April-early May.  This year crabgrass has already been seen near sidewalks and southern facing slopes due to the warmer soil temperatures in these areas, the neighboring soil is not far behind.


The good news is you still have options. The two most common herbicides used to control crabgrass preventatively are dithiopyr found in ArmorTech CGC 40 and prodiamine found in ArmorTech Kade.  These herbicides are also found in many different fertilizer blends.  Prodiamine is a great choice when a longer window of control is needed but must be on the ground for several days before it starts working.  Prodiamine provides no post-emergent control on germinated weeds.

Dithiopyr has a shorter window of protection that makes it safer for areas where fall seeding will be needed.  Dithiopyr is also effective for post-emergent control while the weed is in the 1-3 leaf stage.  Dithiopyr should continue to be an effective control option for the next few weeks or possibly longer if we return to cooler weather?  If you have prodiamine by all means get it out!  Any crabgrass that’s germinating now is going to be very spotty and prodiamine will still give you a wide blanket of protection.  However, be alert and ready to make an early post-emergent application of Quinclorac.  Quinclorac is the active ingredient in QuinStar and is effective on young and fully mature crabgrass.   Get with your ATS rep for more detailed information on how to use quinclorac.  Also, some lawn care applicators may consider a second application of pre-emergent for their customers who received an early application round one.  Check with your ATS rep to discuss if that option is one you should consider.