Soil @ 43°F (6°C): Deploy Crabgrass Preventer or wait to 50 (10)?

Jul 2, 2007
Just took soil temp, got about 43 degrees Fahrenheit, i.e. 6 Celsius. Crabgrass germination happens at about 55 F. Should I deploy now and risk loss of potency and/or wash out, or wait until soil gets up to about 50? Scott's brand crabgrass preventer with built-in fertilizer. I have enough on hand to treat yard twice at the recommended spread rate. What do you think about hitting it now, then follow-up at 50 degree soil temp with a second application? Can you cause problems with a double application like that? Did not treat to prevent crabgrass last year, and had it bad throughout yard last summer. Have a good stand of Kentucky 31 Fescue, but the crabgrass got ahead of me last year because I didn't treat to prevent germination. I want to knock it out before it ever wakes up this year.
Way to early for fertilizer and crabgrass prevention. Hold tight still a little ways to go. Scott's fertilizer is mostly fast release so it will be no use to the grass it's still dormant. Soil still to cold for any seed to sprout.
If your crabgrass was that bad last year I would hold off on the Scott's and buy a crabgrass prevention with dimension as the main ingredient mixed with no fertilizer. You won't find it at a big box store but Amazon does have it. Get it in granular easier to apply. It's superior to Scott's ingredients. 4to6 weeks later you can apply the Scott's for additional protection and fertilizer. Come early fall you can apply the second application of Scott's to help summer recovery and prevent winter weeds including POA from germinating.Only downside with the fall application is you won't be able to over seed it stops all seeds from germinating.
yeah, way too early in the Midwest. Per the MSU site, application when soil temps are between 50-55 is ideal but real crabgrass germination doesn't really start until soil temp is between 60-70. Typically the forsythia blooming is a good indicator of proper soil temps and timing. If you're talking Scotts you also have a fairly short window of time the product is effective...doing it too early will limit the effectiveness. Be sure to also do a Fall application, too, to prevent the next round of weed germination.
How were you measuring the temp? A warm day or two is Feb is no reason to drop pre-emergent. I usually end up in early-mid April here in Michigan.
Last year I used Prodiamine WG (yellow powder) and applied in a sprayer in April, and wish I would have reapplied in may/june as a later germination of crabgrass came in with hot weather. My suggestion is to put down a pre-emergent just before you start mowing and again in a month to carry you through July and reapply for late summer. My experience last summer was very little crabgrass until July from a single application in mid April.
Keep in-mind that my lawn gets regular fertilizer treatments (4-5) and I need to cut the grass twice a week May-Sept). I wait on the Crabgrass treatment until the first full lawn cut. Not the prior cut where grass only grows a foot tall alongside the house. About 4-5 weeks later (3rd week of May), I put down Grub Control.
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