LAWN: What type of fertilizer do you intend to use this spring?

Ammonium sulfate
Extended Slow Release i.e. Duration

Update (03/16/2015)


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Spring Marching Along A.  A cool start to March has given way to above average temperatures.    - Source: Pat Guinan   B.  Varying precipitation amounts over the last 30 days have led to a kaleidoscope of colors in Missouri. - Source: NOAA

Welcome back to spring everyone, or at least officially on Friday.  After winter storm Thor dropped his thunder on much of Missouri in early March, (5” of snow here in Columbia, 9” in Cape Girardeau, and more farther south), it’s incredibly enjoyable to bask in these current 70°F + temperatures.  The very quick snowmelt left many soils saturated, however, which impeded those looking to get out a bit too quick to mow off the winter frass or break out the heavy machinery.  Temperatures have been above average for a little over a week now, and the forecast has the region enjoying today again before a round of Canadian air dips us back down to normality.  

In Missouri, 2” average daily soil temperatures have breached the 50°F mark.  The outlooks over the next 6-10 and 8-14 days from the National Weather Service halt our current warmth, however, and should moderate these soil temperatures back to our normal average in the high 40s.  There’s a solid rain chance mid-week in southern Missouri, but NWS precipitation outlooks are low for the next 6-10 days and a bit higher towards the end of the month.

As you can see in the figures below, soil temperatures were well below normal and frozen just a little over a week ago, so the ascent into spring has been rapid and has caused some of the daffodils to bust out of the ground.  Winter did seem long and cold this year due to this late blast of temperatures. February 2015 in Missouri was the coldest since 1989 (11th coldest overall), and dragged the entire winter average temperature (Dec-Feb) in Missouri to below normal.  Fortunately for potentially susceptible warm season turfgrasses, a few blankets of snow accompanied the chill, and no reports have yet come in of suspected winterkill.   

Soil Temperatures from Horizon Point - 3/14/15:   *Average soil temperature for 3/14 indicated.   A. Bootheel - Portageville, MO                      C.  St. Louis - Williamsburg, MO  B. Springfield - Lamar, MO                             D.  Kansas City

Quick Hits

Yellow Patch of Creeping Bentgrass Symptoms of yellow patch (or cool season brown patch) caused by Rhizoctonia cerealis can be either  (A) smooth or (B) scalloped rings.

  • Cool Season Brown Patch (Yellow Patch): A picture was emailed in from southern Missouri last week after the Thor snowmelt that resembled yellow patch on creeping bentgrass.   We often also see this disease on our ‘Penncross’ MU research green, but have not yet this spring.  Yellow patch, caused by Rhizoctonia cerealis, is seldom a damaging disease, and when temperatures increase to allow bentgrass greenup and suitable growth often disappears.  In the case from the picture above, no residual damage occurred and the bentgrass has since greened up nicely.  The disease may be confused with Microdochium patch (or pink snow mold), however, so if you are uncertain it is a good idea to send it in to a diagnostic lab to check.

  • We haven’t received any reports, samples or whispers of Microdochium patch activity on greens.  This is somewhat surprising considering the adequate amount of snowfall the region experienced late in the year, but perhaps everyone was covered or the environment wasn’t as suitable as believed.   

  • Spring Cool Season Turfgrass Seeding: This difficult enterprise, full of pitfalls and pure dependence on Mother Nature, should be done now in Missouri.  With the current warm spell, and nothing in the immediate forecast to cause a complete kill of seedlings, this mid March timing may afford enough growth to harden plants before the summer siege of weeds, stress and disease ensues.  If you’ve got bare areas or need to replace some large patches of dead nettle or henbit, don’t look this potential gift horse in the mouth.  For information on establishing or renovating a cool season lawn, click here.    
  • Preemergent Herbicides:  The yin to the preceding section yang is preemergent herbicide application.  Our current warm spell and associated soil temperatures and base 32 growing degree days (175) have us on the early verge of the crabgrass preemergent application timing.  With temperatures set to decline, however, we should hold for another week or so in this window.  Now for the yin… remember if spring seeding to not apply a preemergent over seed or newly emerged seedlings. Siduron (Tupersan) and mesotrione (Tenacity) are suggested preemergents that should not harm 2-4 week old seedlings, however, still make sure to wait until early-mid April to use if seeding now.     
  • Poa Seedheads: Poa that has emerged close to heat surfaces (rocks, driveway cracks) in my landscape is starting to set seed.  This is by no means an indicator to action, but for those trying to manage Poa seedheads on golf greens it does mean it’s time to pay attention.  I highly advise those using PGRs to stave off seeding to routinely monitor the growing degree day tracker ( to time their applications.  The tracker is operated by Michigan State University and provides a wealth of information regarding degree day models that should be utilized for weed and insect timing.  In Columbia, we are currently at 175 DD32  and their model stipulates a target range of 220 – 501 DD32 for Proxy/Primo application to curtail Poa seeding on greens. 

Are We There Yet?

Average Dates for Last Spring Frost in Missouri

I’ve been asked a few times “are we there yet?” for preventive disease control for fairy ring/ dollar spot/etc. on golf greens and the answer is no.   The early March thaw is nice, but it is still mid-March after all and April is normally go-time.  This doesn’t appear to be turning out like March 2012 (see this report to relive it again), which was the hottest March on record at 15 degrees above normal.  Also, early-mid April is when we can expect our last 32°F frost according to older 1971-2000 data, (a new updated map and frost/freeze information will be available from the MU Climate Center soon).    

We are on the precipice of all the action though, as noted above with crabgrass preemergents and Poa seedhead control on the horizon, and preventive disease controls ensuing soon after.  The blades for rotary mowers should be sharpened or replaced, the reels on reel mowers should be ground, ready, and for many rolling, and spring applied products should be in hand and have a plan… because in the immortal words of Papa Smurf, “Not much farther.”   
Have a great week.


Lee Miller
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Extension Turfgrass Pathologist
University of Missouri