Dawg days of summer

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.

Dawg days of summer has always been one of those sayings that floats around every summer when we get to late July/early August. The saying typically signifies some hot, humid, nasty weather that causes us all to slow down and search out some air conditioning. I’ve noticed this slowing down behavior not only in my slightly used puppy (Can’t call him new anymore since he was rescued from doggie jail back in May.), but also in my lawn that has been crawling along the last couple weeks.

Most of our lawns in Michigan are predominantly Kentucky bluegrass with some portion of perennial ryegrass and fine fescue mixed in for good measure. All of these grasses are cool season grasses, and as you can guess and most likely observed, start to slow down their growth as temperatures soar into the 80s and 90s. Some turf managers, especially homeowners, make the mistake of trying to push the grass to achieve dark green color and more regular growth this time of year by fertilizing. Even if you have an in-ground irrigation system, that can be used to even out the peaks and valleys of our sporadic rainfall, use restraint in applying fertilizers during this time period. The last thing you want to do to the turf right now is stimulate top-growth by fertilizing. Forcing top-growth during this time of summer can make the turf more susceptible to a bevy of turfgrass diseases that can emerge during the hot, humid nights. If you want to fertilizer, use slow release sources at moderate rates, but I would suggest for most folks to give the fertilizer spreader a rest and let Mother Nature take its course. As the weather moves towards fall, the turf will enjoy the milder temperatures and active growth will resume.

Tolerating weeds

A couple weeks ago in the June 30 issue I reviewed postemergence control options for crabgrass. Now what about all those broadleaf weeds that may be troubling you? With respect to postemergence applications to control broadleafs, the first thing to remember is that if you can live with the occasional weed through the summer, the most effective time to control is in the fall. Applications can be effective in the summer, but follow these simple tips.

First, don’t spray when temperatures are above 80°F: you might burn the turf at high temperatures. Second, just as the turf slows growth and activity when temperatures rise and rain becomes scarce, so do many broadleaf weeds. Applications during peak summer stress periods may not be very effective because the weeds have toughened up and are just trying to make it through the tough conditions. Third, for those with some knowledge of herbicide chemistry, consider using an ester formulation because it will be more effective at penetrating the thick cuticle/skin of the weeds. Finally, remember fall applications are very effective in controlling broadleaf weeds.

Dr. Frank's work is funded in part by MSU's AgBioResearch.

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