Summer Turfgrass Update: A look at the growing season to date and some tips for late summer maintenance.

August 1, 2012

by Sam Bauer

If you’re reading this, odds are that your home lawn has been on a rollercoaster ride this summer and you’re wondering what happened and where to go from here.  The good news is YOU ARE NOT ALONE.  A quick look back at the climatological data for the Twin Cities from March until now puts the struggles of the 2012 growing season into perspective.  In mid-March we saw highs in the upper 70’s, and actually recorded a high of 80° F on March 17th.  And just when your lawn thought it was time to start growing, it was reminded that summer was still a long way off by the average spring temperatures in April.  Timing for pre-emergent application to control summer annual weeds was difficult at best.  During this time I was in Florida trying to get a handle on the mole cricket population before THE PLAYERS Championship at the TPC Sawgrass.  If you’re scratching your head wondering what a mole cricket is, you don’t want to know.  Anyway, I heard the cries for help from homeowners and turfgrass managers in Minnesota at this time. 

The first week of May brought warm weather and rain, a perfect combination for disease infection and weed germination in your lawn that was just beginning to show signs of life.  Then the middle of May came, no rain in sight.  Homeowners with irrigation systems were able to survive this stretch through supplemental watering, but the rest of us were wondering when our soil moisture would be replenished.  And, just when we asked for it…….a gusher 3” of precipitation on May 23rd and 24th.  June was a rather normal month, but we were still playing catch up from the less than adequate conditions in May.

As I write this, it’s August 1st. Looking back on the month of July that averaged 7°F above normal (the 2nd warmest July on record in the Twin Cities), we should feel very fortunate to have had close to average rainfall totals in the Twin Cities.  Others around the state haven’t fared as well.  With severe drought conditions in northwestern and southeastern Minnesota, or the massive flooding that left Duluth under water, we’ve had a pretty easy go of it here in the metro.  This blog post from Chris Tritabaugh of Northland Country Club in Duluth, MN describes the flood event: http://northlandgrounds.blogspot.com/2012/06/course-assessment-at-this-time.html

What does mother nature have in store for us this fall?  Only time will tell.  It’s in our hands to create the best growing environment (mother nature aside) for our turfgrass and there are many maintenance practices that will help…… now is the time to start preparing.  Bob Mugaas, the previous Turfgrass Extension Educator, wrote a great blog in 2009 titled “Lawn care checklist: late summer – early fall.” It can be found through this link: http://blog.lib.umn.edu/efans/ygnews/2009/09/checklist-for-late-summer—ea.html  The blog post here is not meant to re-write Bob’s recommendations, but to rather direct you to them.

Below are some additional tips and important links:

 

Irrigation: During the summer months your irrigation practices should have shifted from deep (or heavy) and infrequent to shallow (or light) and frequent.  At this time, cool-season turfgrass root systems are shallow and shortening the frequency between irrigation cycles is important.  The general rule of thumb for irrigation in our area is 1 inch of water per week, but this will depend on your turf species, soil type, microclimates, and weather conditions.  My suggestion is to consider all of these factors and follow ET (evapotranspiration, water loss through evaporation and turfgrass transpiration) data from a credible source.  Follow this link for MN/WI ET data:  http://www.soils.wisc.edu/uwex_agwx/sun_water/et_wimn  The goal coming into the fall is to start training your turfgrass roots to grow deeper into the soil.  This is accomplished by stretching the time between irrigation cycles.  Constant moisture at the surface encourages a shallow root system and therefore an unhealthy lawn.  

Fertility: Labor Day is still the right time to fertilizer your lawn.  Try to find a fertilizer with a good portion (at least half) of nitrogen in the slow release form.  Read the fertilizer label!  Slow release nitrogen products include: sulfur or polymer coated urea, methylene urea, urea formaldehyde, isobutylidene diurea, or organic.  We still recommend 1/2 to 2/3 of your lawns yearly nitrogen requirement to be applied in the fall.  Phosphorus and potassium applications should be based on the requirements indicated by a soil test.  Soil tests are $15.00 from the University of Minnesota Soil Testing Laboratory: http://soiltest.cfans.umn.edu/

Cultivation: Fall is also a great time for lawn aeration and thatch control.  Be sure to get these practices on your schedule now if compaction and thatch are issues in your turfgrass environment. 

Pest control: Perennial broadleaf weeds are best controlled in the fall and there are numerous products that will work to help eradicate them from your lawn.  If you are not sure what weeds you’re dealing with, visit:  http://www.extension.umn.edu/gardeninfo/weedid/index.html

On a final note (and to keep this blog from taking up all your time): CHOOSE YOUR FALL LAWN CARE PRACTICES WISELY.  Fall is the time of year to set your lawn up to go into the winter in a healthy state, and your maintenance practices will determine the outcome next spring…..ultimately setting you up to get through the stresses of the 2013 summer (yeah, like you envisioned next summer to be easy).

Contact your local extension educator with questions.  I can be reached at: sjbauer@umn.edu or 763-767-3518.  Good luck!

Sam

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