"Airkings" wrote in message
nk.net...
I'm in Minnesota, which I believe is Zone 4 for the most part.

southern part is zone 4- northern part is zone 3

Like a lot of
people, crabgrass is a part of my lawn. Overall the lawn looks pretty
good,
but the crabgrass is encroaching.

crabgrass poisons the soil under it and kills other grasses - you either
remove any crabgrass that gets by your treatment this year or repair dead
patches by replacing some poisoned soil next year..

There are several approaches to crabgrass control

1) Stop it from starting:
Cheapest and most effective - pre-emergent. It is very effective on
crabgrass when applied around mid-may in Minnesota.
An application now will mitigate further damage, but it won't kill what
has already sprouted, which is over half the crabgrass.

A caution - a) pre-emergent and crabgrass pre-emergent are the same stuff,
used for the same purpose for different weeds, b) the stuff decays, and c)
crabgrass needs a good dose to keep it dormant.

Pre-emergent only lasts (protects) 6-12 weeks before it breaks down,
depending on how heavy you put it down. So you have say 10 weeks from when
you put it down.
Crabgrass requires 3 days of soil temp around 70-80 degrees to
germinate - usually mid-may in mid-southern Minnesota.

Pre-emergent is now being sold as a general weed preventative, which it is
if you put it down early, like in April in southern Minnesota - BUT IF YOU
WANT it to only be a crabgrass preemergent that lasts most of the season,
then you need to get it down later.

Timing goes like this - put it down in April, and it is pretty much gone
in 3 months - that means crabgrass will sprout in late July and August, if
you don't re-apply in late June.
But put it down in mid may, and the late august nights are too cool for
the stuff to sprout and get a foothold.

2) Kill the young:
- Once crabgrass starts, get the young stuff with methanearsenate [sp].
It's a little pricey, but crabgrass will spread and posion the grass, and
the stuff works. You may need a second application to get all the
crabgrass.
The stuff is usually labelled crabgrass killer. Ortho makes one, as do
other mfgs.

3) mechanical removal - Use a crabgrass rake to lift the tendrils (or lift
them by hand), and then pull out the crabgrass by hand, one plant at a time.



Is there any way to poison or kill the crabgrass at this time of year? Or
did I miss my chance in the spring?

There's too much to spray with one of those Windex-type bottles of Ortho
or
something, so is there some kind of broadcast spray that will only kill
crabgrass?

yes -


Thanks!

--
Dave