I bet this is an annual question. I think I have been applying mine to
early, usually after my grass has started to grow and I have mowed it once
Here is what I found during my quest for knowledge today! I was hoping to
find a straight forward answer, like some soil temp, but even that advice
-Start taking your lawn soil's temperature early in the morning. When it
reaches 55 degrees, apply crabgrass preventer.
-Apply crabgrass preventer as soon as established tall fescue and Kentucky
bluegrass lawns green up and start growing well.
-Crabgrass preventer halts the seed-sprouting process. If applied after this
year's crabgrass germinates, it will have no effect. The only exception to
this rule is a rather new product - dithiopyr - sold in a
herbicide-fertilizer mix called Dimension.
-Apply when temperatures reach around 70 degrees for a consistant period of
time, typically for more than 2 or three days.
-Apply in early spring before weeds sprout (before temperatures are
regularly in the 80's).
-When the forsythia bushes starting to flower, or the redbud trees start to
bud, or before the dandelion weed puffs and spreads. (Hell, I don't have
any of these in my yard!)
Anyone want to add their $.02?