HOME GROWN 296 April 13, 2005

I am so confused. I am seeing crabgrass preventer in a bunch of stores and every store clerk tells me a different time to put this down. I have been told everything from February, on top of the snow, to Memorial Day. So when is the right time? The label doesn’t say anything specifically for Michigan.

That’s because the label is for bags that go all over this great, big country of ours. If you think the label is long now, add fifty states with application times. Timing is relatively easy when we’re talking crabgrass. But first, a look at the “Crabgrass Primer of Valuable Facts.” Crabgrass is an annual. This means that it comes up each year from last year’s seeds. If you are seeing undesirable grass now, it isn’t crabgrass. Your future crabgrass is only a tiny seed in waiting somewhere in your lawn. The crabgrass preventer will prevent all seeds from germinating so don’t entertain the thought of overseeding good grass seed while preventing bad crabgrass from growing. This is a product that does not discriminate. And now, for the magic application time. Crab grass preventer needs to applied at the time that Forsythias in your neighborhood are blooming. Those are the shrubs with the arching branches covered with brilliant yellow flowers. About two or so weeks after the forsythias are finished blooming, crabgrass seeds will be germinating. We’re using the Forsythia as an indicator plant. It’s blooming and crabgrass germinating are always in the same order with the same timing. Using a calendar date with Michigan weather will always be difficult. Tossing it on the snow will get the product there way too early. One gigantic rain will float your crabgrass stuff to the nearest ditch or to your neighbor’s lawn. To have the best opportunity for success, getting crabgrass preventer down just before the seeds begin to grow is best. Just remember that the stores sell stuff but don’t necessarily know about what they are selling. Just remember: Forsythia bloom...apply crabgrass doom.


In the last couple of weeks since it has been warmer outside, I am finding many black, slightly hairy flies sitting on my windowsills. When I went out and looked at the outside of the house, there were hundreds sitting on my siding. Why are these here? I saw the same thing in a movie called "The Amityville Horror."

Here’s a bit of information. That movie was not a documentary. It was a movie based on a book where the author took much literary license. Or in simpler terms, he lied. Your mystery flies are not being sent by headless demons. They are just average, mundane Cluster Flies. This insect has nothing to do with decaying organic matter, like houseflies. The adult Cluster Flies feed on pollen and sap and the juveniles are parasites of earthworms. They create virtually no environmental damage and are of little consequence outside. Their main claim to pest status is that they overwinter in buildings. They, and a couple of dozen other insects, spend the winter as adults. They crammed themselves under the siding for winter protection. The really clever ones made it all the way to the wall void. When they warmed up this early spring, they got dumb and made a wrong turn and ended up in the house. The ones on the siding are going out, not trying to come in, so ignore them. The ones in the house would also like to be outside, but they aren’t. Suck them up with the hose attachment on the vacuum cleaner. In mid May or June, cruise around 
outside and look for entry points for insects. Cracks and crevices of any kind are places that overwintering insects will be looking for in late September and October. Caulk them closed and don’t do insect research on the sci fi channel.

Gretchen Voyle, MSU Extension-Livingston County Horticulture
Agent 517/546-3950

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