ST. LOUIS – The weather plays an important role in St. Louis turf and landscapes. From how much or how little rainfall we receive to how long those triple-digit heat waves last, maintaining a green and healthy lawn takes some work.
Jeff Travers, a horticulturist, turf expert, and father, says this is because St. Louis lies in the transition zone between warm-season and cool-season turf.
“What you battle with on your forecast, cold, hot, when do the storms come. That’s the same thing our turf has to battle with. These wild fluctuations in temperature,” he said. “So, there’s a stress placed upon turf because of that. The combination of weather extremes and clay soil makes growing turf very difficult here.”
While these wild weather fluctuations make keeping a healthy yard through the summer tough, it’s not impossible. There are four key components: crabgrass control, proper irrigation, proper mowing height, and a sharp lawnmower blade.
Crabgrass preventer typically needs to be applied by April 15. Thanks to the relatively cool season and late frosts, there aren’t too many seedlings germinated yet. But it is still essential to get something down.
“If you haven’t done your crabgrass product, you want to use a product called Dimension. The active ingredient is dithiopyr and it will actually kill a small crabgrass plant,” Travers said.
You don’t need to water as long as mother nature gives us two good soakings a week. When it is dry water three times a week before 8:00 a.m. to reduce disease potential. Overwatering is a common mistake. This causes your grass to have a shallow root system which means it won’t be able to handle heat stress come mid-July.
“You want to get a rainfall shut off or rainfall override switch if you have an irrigation system. There’s nothing worse than getting a really good soaking from mother nature and then have your irrigation system go on,” Travers said.
“The most common mistake I see as I drive through subdivisions in the community is people that scalp their grass. When you mow short, your grass gets stressed. Grass grows from the bottom up and the growing point needs to be cool. So if you mow high the growing point at the surface of the soil is cool.”
Sharpen your lawnmower blade about every eight weeks and have a back up ready.
“If you shatter or tatter the leaf tips it’ll be torn and the plant can’t heal and disease organisms can move in. It’s like the main line straight into the plant. If you’re mowing with a dull blade you will spread your disease,” Travers said..
One more mistake people make is over-fertilization and improper nitrogen management during the spring and summer months.
“A lot of the products you see in the big box stores have way too much nitrogen for use in the transition zone. They’re fine for the south and they’re fine for the north but they’re still marketed here in St. Louis,” Travers said. “In the springtime you want your crabgrass product, and all your other fertilizers, to have 12 percent or below on the nitrogen.”
Proper nitrogen management reduces the risk of a brown patch disease. An organic fertilizer, low in nitrogen and therefore great to use during the summer months, is milorganite. Wait until the fall to apply fertilizer high in nitrogen.