When to apply preemergent for crabgrass - Ask Extension
I read sever conflicting articles on when to apply a preemergent for crabgrass. One arrival says when soil is between 55-60 for four days straight. An...
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When to apply preemergent for crabgrass #864612
Asked April 15, 2024, 2:39 PM EDT
I read sever conflicting articles on when to apply a preemergent for crabgrass. One arrival says when soil is between 55-60 for four days straight. Another article says after May 30. I'm so co fused. I have so much crabgrass I just want it gone. So when do I apply it? Also I have bare spots from last year's crabgrass. When Is the best time to over seed my lawn? I can't apply a preemergent and over seed it at the same time or close to it.
City is Wyoming Mn.
Chisago County Minnesota
Expert Response
It's not rocket science. Soil in some areas of your yard (near sidewalks and buildings) will warm much faster than other areas. Here is a handy map that shows optimal time for applying pre-emergent herbicides (which is pretty much now):
https://gddtracker.msu.edu/
As for the bare spots, there are a couple of ways you could go. If you're willing to wait, use a pre-emergent now, then pull or treat weeds (for instance, with Roundup) as they emerge. Then seed in late summer (the optimal time for seeding):
https://extension.umn.edu/planting-and-growing-guides/lawn-care-calendar
If you can't wait, there are post-emergent products (look for the ingredient Mesotrione) that can be used at the same time as seeding. My understanding is that it is not a true pre-emergent, but a post-emergent product. Be sure to follow the labels with these products. Read here:
https://turf.rutgers.edu/blog/weed-control-in-spring-seedings/
There used to be a product (Tupersan) that was a true pre-emergent and could be used while seeding the lawn, but it is no longer available.
https://gddtracker.msu.edu/
As for the bare spots, there are a couple of ways you could go. If you're willing to wait, use a pre-emergent now, then pull or treat weeds (for instance, with Roundup) as they emerge. Then seed in late summer (the optimal time for seeding):
https://extension.umn.edu/planting-and-growing-guides/lawn-care-calendar
If you can't wait, there are post-emergent products (look for the ingredient Mesotrione) that can be used at the same time as seeding. My understanding is that it is not a true pre-emergent, but a post-emergent product. Be sure to follow the labels with these products. Read here:
https://turf.rutgers.edu/blog/weed-control-in-spring-seedings/
There used to be a product (Tupersan) that was a true pre-emergent and could be used while seeding the lawn, but it is no longer available.
