You do not have to be a weather expert to know that March 2013 is much different than March 2012! HERE is a great blog post from Dr. Aaron Patton, Turfgrass Extension Specialist at Purdue University.
Bottom line - Crabgrass germination will be much later in '13 than it was in '12. So, if this weather trend continues, granular pre-emergent products will be effective when applied at later dates than in 2012. Stay tuned for more information on this topic as the weather warms.
Go to j-dturf.com to learn more about J&D Turf.