|How do you know when the right time is to apply crab grass preventer?
|Answer from NGA
March 17, 2010
|Crabgrass starts germinating when soil temperatures are 50 to 55 degrees F for ten or more days and germination can take place over a 6 week period. Pre-emergence herbicides provide excellent weed control for crabgrass but they last only about 30 days. The compound prevents the weed seed from germinating, but it will not kill the newly sprouted seedlings. Watch the weather - late March or early April is the usual application time in your region. You want to apply the product before you see crabgrass beginning to sprout. A second application might have to be made 30 days later to keep your lawn a little more crabgrass free.
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