Pre-emergent for crabgrass and Clover seeding - Ask Extension
I'd like to establish a clover lawn this spring but had terrible crabgrass last summer and was planning to use a pre-emergent to prevent it this year....
Knowledgebase
Pre-emergent for crabgrass and Clover seeding #819595
Asked February 01, 2023, 3:32 PM EST
I'd like to establish a clover lawn this spring but had terrible crabgrass last summer and was planning to use a pre-emergent to prevent it this year. Will the pre-emergent interfere with the clover seeding process?
Prince George's County Maryland
Expert Response
Unfortunately most if not all pre-emergent herbicides available to homeowners for crabgrass and Japanese stiltgrass will also stop clover from germinating.
Here is our page Options for Managing Common Lawn Weeds in Maryland:
https://extension.umd.edu/resource/herbicide-options-managing-common-lawn-weeds-maryland
You'll note that we suggest that you not use 'Weed-n Feed"-type products but try to find the pre-emergent active ingredient alone without fertilizer.
You will have to read labels to see what the interval time is after application before you can safely plant seeds, which will vary by product.
We assume that you are just trying to add more clover to a pre-existing lawn? Straight clover lawns are not usually done since clover goes dormant and disappears in the winter, which some suggest leaves soil more susceptible to erosion.
As you likely know, it is valuable for it's ability to fix nitrogen in the soil, and it's flowers feed pollinators.
In general we are trying to encourage people to change their expectations about having perfect lawns and instead plant for healthier landscapes and biodiversity. You may enjoy learning more through our page on Lawn Alternatives:
https://extension.umd.edu/resource/lawn-alternatives
Christine
Here is our page Options for Managing Common Lawn Weeds in Maryland:
https://extension.umd.edu/resource/herbicide-options-managing-common-lawn-weeds-maryland
You'll note that we suggest that you not use 'Weed-n Feed"-type products but try to find the pre-emergent active ingredient alone without fertilizer.
You will have to read labels to see what the interval time is after application before you can safely plant seeds, which will vary by product.
We assume that you are just trying to add more clover to a pre-existing lawn? Straight clover lawns are not usually done since clover goes dormant and disappears in the winter, which some suggest leaves soil more susceptible to erosion.
As you likely know, it is valuable for it's ability to fix nitrogen in the soil, and it's flowers feed pollinators.
In general we are trying to encourage people to change their expectations about having perfect lawns and instead plant for healthier landscapes and biodiversity. You may enjoy learning more through our page on Lawn Alternatives:
https://extension.umd.edu/resource/lawn-alternatives
Christine
Thank you! I had trouble finding information either way about pre-emergents and clover. Maybe I will just deal with the crabgrass again this season. We have a distressed yard due to dog activity, so some grass exists but there is a good amount of exposed soil. I think I will use a clover/fescue mix. I am not too concerned with having a manicured lawn per se, but need some groundcover and hate the crabgrass. My wife and I do try to take advantage of tree planting programs and have added more garden bed area, but I don't want to mulch the entire yard.
-Liam
Hi Liam,
One factor that promotes crabgrass abundance is mowing a lawn too short, so in case that applies here, be sure to mow around the highest setting on your mower, and sharpen the blades before each season (or at the end of the prior season) since clean cuts also minimize lawn stress. You can explore more about Crabgrass on our page for that particular weed. As is the case for most lawn weeds, improving the overall health of the turfgrass (clover component aside for the moment) will help it out-compete weeds on its own over the long term, which will reduce any dependence on pre-emergent going forward. These measures include annual autumn overseeding (with fescue in this case), testing soil every few years and fertilizing as appropriate based on those test results (liming as well, if needed to adjust pH), and potentially core-aerating every few seasons if high foot traffic is keeping the soil compacted. We have a page about clover use in lawns, and recommend that the type you use is microclover (a dwarf form of white clover) since it is more compatible with the turf. The link at the bottom of that page goes to a PDF publication which provides more detail about clover seeding rates, timing, and other aspects of care.
Miri
One factor that promotes crabgrass abundance is mowing a lawn too short, so in case that applies here, be sure to mow around the highest setting on your mower, and sharpen the blades before each season (or at the end of the prior season) since clean cuts also minimize lawn stress. You can explore more about Crabgrass on our page for that particular weed. As is the case for most lawn weeds, improving the overall health of the turfgrass (clover component aside for the moment) will help it out-compete weeds on its own over the long term, which will reduce any dependence on pre-emergent going forward. These measures include annual autumn overseeding (with fescue in this case), testing soil every few years and fertilizing as appropriate based on those test results (liming as well, if needed to adjust pH), and potentially core-aerating every few seasons if high foot traffic is keeping the soil compacted. We have a page about clover use in lawns, and recommend that the type you use is microclover (a dwarf form of white clover) since it is more compatible with the turf. The link at the bottom of that page goes to a PDF publication which provides more detail about clover seeding rates, timing, and other aspects of care.
Miri
