Early spring 19-0-6Dimension
Late spring same thing again
Early Fall18-24-12 for overseeding
Late Fall 34-3-11a/m(quick release)
and spot spraying broadleaf weeds all season with Momentum
One app of Pre hasn't worked here in the Northeast for 2 years in a row now. URI weed scientists have found that instead of one big push during the first 2-3 weeks of May, we're now seeing regular slow steady Crabgrass germination from mid-May through August. No single app of any Pre is going to last that long.
2 Pres are a lot cheaper than chasing service calls.
Or, space the PreM's two aps appart. Doing them consecutively, basically, is a waste. If they are labeled to last 8 to 12 weeks (12 being unrealistic - only in complete non-precipitation conditions), then a regular ap should be done in between. This would extend the barrier out longer, rather than just have them overlap.
I might be missing something here. If you make your fist app on April 1st with any Pre, the barrier will last from 6-10 weeks. Most of the LCO's I know make apps every 8 weeks. So if they wait until Round 3 to do the second Pre (about 16 weeks after April first *if* they saty on schedule), there's going to be lot of Crabgrass to deal with.
R1) Apr 1....1st Pre
R2) Jun 1....2nd Pre
R3) Aug 1...Grub season & too late for more Pre.
Nothing has done more harm to good crabgrass control than Merit. LOL.
Dimension lasts much longer at the higher rate and gives control in to and through August (as long as the weedwackers and mowers, and dogs and....don't break the barrier). In Michigan that is sufficient. I can see how you might need more down South.