Monday, March 26, 2012

About a Month Ahead

It will come as no surprise to most people, but we are about a month ahead of were the calendar says we should be. With the weather the last week and a half (10 days in a row above 70 degrees and three in a row above 80), it is time to start thinking about things we would normally do toward the end of April.

One of the tools I use a lot in the early spring is Growing Degree Days (GDD), which is a measure of time with a temperature above a certain set point. Michigan State University has a website set up which tracks GDD for a number of different factors. You can find it in the links sidebar on my website or by clicking HERE. One of the biggest things I follow at this site is Poa annua seedhead flush. Poa is an annual grass that invades our greens surfaces. When it produces seed, the seedheads make the greens bumpy. You can read more about it from an earlier post. Here is a picture of the seedheads on a fairway.

We put down a plant growth regulator called Embark, paired with a fungicide named Civitas to limit the production of seedhead on the greens. Last year we sprayed this on April 21st, when the GDD was 888. This year, we are putting it down on March 26th. The GDD is 936. The target GDD is between 680 and 1050. I wanted to wait a little while longer this year because it is so early. I am just not convinced that seed production is solely based on temperature. The total GDD is still within the optimal range, however.

One other useful set of data that can be tracked is crabgrass pre-emergent. If you look at the GDD Tracker website, you will see that we are slightly past the optimal time for putting this down. The suggested range is between 250 and 500 GDD. (This number is different than the seedhead GDD because of the base temperature that they use to calculate GDD.) There is still time, however, before the window totally closes. One thing I learned from my internship is to watch for Forsythia blooming. I was told that when it blooms, you should put down crabgrass pre-emergent. In my experiance, it is usually pretty close to when the GDD Tracker is recomending it.

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