Originally Posted by Smallaxe
CrabGrass germinates in the heat of Summer, not Spring time , then stay dormant... the pre-m needs to be in place when the CG is germinating NOT 2 months before...
From this I will suggest to seek advice from your State/county extension service. Around here, down SOUTH (if you will), we are told that late March to early April is the time to apply a pre-emergent...though this can change with an early or late Spring. This has most to do with ground temps I believe.
AND, this is another reason that a later application of pre-emergent that the big boy chem companies make in mid-late May (around here, mind you) is useful for crabgrass control. Those DANG crabgrass seeds can germinate at virtually anytime prior to their ritual infestation in Summer.