Signs of spring

Editor’s note: This article is from the archives of the MSU Crop Advisory Team Alerts. Check the label of any pesticide referenced to ensure your use is included. 

We all have our own signs of spring that cause us to think every year that spring is just right around the corner. I have several signs that I always look for. I saw the my first robin just yesterday, the air just smells a little more like spring, March Madness basketball has begun, and of course the true first sign of spring, I saw both the first Scotts Fertilizer and RoundUp TV ads of the season. I don’t think it’s any coincidence that these ads pop-up around the time of the big basketball tourney. What better way to capture the attention of millions of couch potatoes who are on the cusp of lawn care season.

Despite the inclination to go out and throw down some fertilizer to get that lawn going, as always the best advice right now is to have some patience. After last weekend’s spring preview, many folks are mighty anxious to get rolling, but the advanced forecast doesn’t predict temperatures out of the 30s until at least March 24 or 25. Using my crystal ball, I’m going to predict that the earliest we’re really going to see the turf growing is probably around the first week of April and that’s assuming (you know what they say about assumptions) that temperatures really start to warm the last week of March.

Bottom line is that you don’t need to be applying any fertilizers or preemergence herbicides until the turf is actively growing. Wait until you’ve at least mowed the lawn before you worry about applying anything. Applying high rates of fertilizer now will encourage excessive top-growth and has the potential to reduce summer stress tolerance later on.

The 2005 crabgrass plague

In 2005, there is little argument that crabgrass was victorious and many a homeowner and lawn care professional spent much of the summer licking their wounds as the crabgrass thrived under the scorching sun. What happened? Well probably the best answer is quirky Michigan weather. The majority of crabgrass germination occurs when adequate moisture is present and soil temperatures are between 60 and 70ºF at 0- to 2-inch depth. In May 2005, the temperatures were adequate, but there wasn’t any moisture so the crabgrass didn’t germinate until mid-to-late May. Late germinating crabgrass likely resulted in poor control from preemergence products that were applied in early April. Some preemergence products provide 6-8 weeks of control, if you do the math it’s easy to see why the crabgrass control suffered. In addition to the late germinating crabgrass the turf suffered from the high temperatures, sporadic rain and overall heat stress. Thin turf + late germinating crabgrass = lots of crabgrass and frustration for turf managers. Last year was an outlier year and hopefully this year the typical application timing will result in adequate crabgrass control.

So how can you try to time preemergence applications to maximize efficacy? No doubt you’ve heard that a blooming forsythia bush is a good signal for applying a preemergence herbicide. However, if you’re a keen landscape observer you’ve probably noticed over the years that some forsythia bushes may bloom earlier than others based on their location in the landscape. If they’re in a nice sunny spot next to a building the forsythia are probably going to bloom earlier than a bush on the north side of a building not getting any sunlight. So as you can see the forsythia indicator may give you a general idea but by no means is it foolproof. If you have a thermometer available, you can check soil temperatures to help gauge preemergence application. Apply preemergence herbicides when soil temperatures at a two-inch depth reach 50°F. In mid-Michigan, the time for applications is usually around the April 15. Before you automatically apply a preemergence herbicide (i.e. crabgrass preventer), consider whether or not crabgrass is a big problem in your turf. Remember that the best way to control weeds in turf is to encourage a healthy, dense turf that competes well with weeds and crowds them out. Mowing high, returning clippings, and having a good fertility program are just some of the practices that will encourage a dense turf.

First mowing

A common practice for the first mowing event of the year is to lower the mowing height to help remove dead tissue and facilitate soil warming which will help the turf get growing faster. Be advised though not to get carried away with this lowering the mowing height recommendation. At most I would drop it 1 inch from your normal mowing height. Be careful, we don’t want to scalp the turf. For most, dropping the height ½ inch (usually 1 notch on your mower) will probably suffice to clean up debris on the lawn from the winter and get that turf going.

Podcasting turf tips and clippings

Well, it’s official, in addition to being turf geeks we are indeed trying hard to be techno geeks. We’ve now launched “Turf Tips and Clippings” on our web-site Turf Tips and Clippings are timely audio clips containing turfgrass management information. Turf Tips are available for a listen at our web-site or for those of you on the run for downloading to your iPod so you can listen wherever you please. So the next time you send Jimmy out to mow the lawn maybe you should encourage him to download some turf tips to that iPod so he can be educated while mowing.

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