By JEFF BURBRINK
Extension Educator, Purdue Extension Elkhart County

A lot happens in your lawn in late April and early May in Michiana. As the turf begins to wake up from its winter slumber, you will first notice it greens up. This is a response to nitrogen deposited by the winter snow and rain.

At first the grass does not grow quickly, despite the lush green color it takes on. Then suddenly in mid-May, as if someone applied steroids to your lawn, it starts to grow like crazy. It often feels like you will never, ever get out from behind the mower. This period of growth signals your lawn is now officially awake.

Rapid turf growth in the spring makes mowing a challenge. There are three basic rules of mowing: mow high; mow frequently; and mow with a sharp blade. By high, we are suggesting two and a half to three inches from the ground to the blade is the preferred height for our local lawns.

The frequency to mow is gauged by how fast the grass is growing. For the best results, removing one-third of the blade at any one cutting is recommended. That is hard to do with schedules being what they are these days. If the grass is allowed to grow too tall, mowing will remove too much of the blades of the grass resulting in a “stemmy” appearance and poor color. Continual removal of more than one-third results in a stressed root system going into the heat of summer. Return clippings to the lawn whenever possible. Many people do not like to do this, however, it recycles nutrients and reduces yard waste.

What is the harm in putting fertilizer on before mid -May? That early dose of fertilizer wakes up the turf prematurely, causing it to grow leaves at a time of the year when it is normally not growing much. The stress weakens the plant, but results often do not show up until August or September, especially in years of drought or unseasonable temperatures. For that reason, I like to encourage people to buy their crabgrass preventer separate from their fertilizer, or at least find a combination product that is low in nitrogen.

Speaking of crabgrass preventer, I had several calls this week about when to apply those products. Unfortunately, we may be just past the optimum time to apply the preventives. Michigan State University has an online crabgrass pre-emergence timer (http://www.gddtracker.net/?model=7), which uses reported temperatures to predict the most timely use. That is not to say preventer will not help the appearance of your lawn. However, it is likely some crabgrass has already germinated.

May is also the month of the dreaded dandelion bloom. At the first sign of yellow blossoms, some people go into attack mode. While using the broadleaf weed killers in May might cause the plants to curl up and take on an injured appearance (which makes you feel better), it rarely kills the plant before they produce seed.

A far better time to control dandelion and many other broadleaf plants in turf is the fall. At that point in their life cycle, the weeds are packing away carbohydrates to help them survive the winter. The herbicides are taken in by the plant, and transported into their root system. If the plant does not die outright, it often cannot survive the winter.

If this article has stimulated your thoughts about managing your lawn, take a look at http://www.agry.purdue.edu/turf/ for Purdue Extension publications, weed identification tips, and a host of other information.