August 3, 2015

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Seeding your lawn this fall? Here are some considerations (Part 1 of 2)

Lawns in Minnesota take a beating.  This is no surprise due to the extreme weather swings that we have from season to season and even within seasons.  Fortunately this year has been a banner year for lawn care with plenty of rain, mild temperatures and low dew points.  However, the current ten day forecast is setting us up to have some of the highest temperatures we’ve seen this summer, with dew points in the 70’s.  We may have another month of hot weather and then it will be time to seed bare areas in your lawn or conduct lawn renovations.  With that, now is the time to start thinking about seed selection and purchasing.

Depending on the condition of your lawn and your goals going forward, I may recommend one of several renovation options and seed mixtures.  Ideally, this work would be carried out from mid-August to mid-September.  Renovation strategies can be grouped into four categories:

  1. Lawn improvement- conducted when less than 20% weeds or bare soil are present. The goal is to utilize existing grass species and determine the factors leading to poor lawn quality and correct these.  Often, recommended practices for improvement will include aeration, fertility, seeding, and weed control.
  2. Partial renovation- conducted when 20-40% weeds or bare soil are present. This process requires stressing the existing vegetation to reduce the competitive advantage of existing species, while overseeding with new (possibly different) turf species.  Depending on the weeds present, herbicides may or may not be recommended.
  3. Species conversion- conducted when greater than 40% weeds or bare soil are present, but there are no major soil issues. This process requires killing the existing vegetation by the use of non-selective herbicides or solarization (plastic sheet) and overseeding with new turf species.  The species conversion process allows you to change the function of the lawn (ex: low input, no mow, high traffic tolerance) by establishing new species in a short period of time.
  4. Complete renovation- conducted when greater than 40% weeds or bare soil are present, and soil remediation is required. This process is essentially the same as the species conversion except soils will be tilled, graded, and possibly amended with organic matter or nutrients.

For more detailed information about all of these renovation strategies and in-depth detail on how to conduct the species conversion, view this webinar: Lawn Renovation

No matter which renovation strategy you choose, selection of the proper seed will be critical to the long term success of your lawn.  I would generally suggest utilizing a mixture of several turfgrass species to overseed with, but let’s discuss the species individually and next week we’ll look at some mixtures that are available to you.

Mixtures vs. Blends

Mixtures are different from blends.  Blends of grass seed include only one species, for example Kentucky bluegrass, and most blends would have 3-4 different varieties of that species.  Mixtures of grass seed include two or more species and greater genetic diversity.  Mixtures are often utilized for lawns that have differing microclimates (ex: sun and shade).


Leaf texture differences between tall fescue (left), Kentucky bluegrass (center), and fine fescue (right)

Cool Season Species for Minnesota Lawns

Kentucky bluegrass is the most widely used species in Minnesota lawns due to its high aesthetic quality, adaptation and stress tolerance.  If you have an existing lawn, chances are that a good majority of it is Kentucky bluegrass.  Additional benefits of Kentucky bluegrass include its cold tolerance, drought survival through dormancy and high recuperative ability.  However, downfalls with this species include a high water requirement, frequent mowing and high fertility needs.  There is a wide range of genetic diversity in Kentucky bluegrass and Seed Research of Oregon has put together this great classification of the different varieties: Kentucky Bluegrass Classification.

Perennial ryegrass can also be a high quality species, although its poor tolerance to winter and summer stresses make it undesirable in many cases.  Perennial ryegrass is included in many of our Midwest mixtures due to its incredible germination and establishment rate.  If quick establishment is desired, perennial ryegrass can be used, but I would suggest not using more than 25% perennial ryegrass in your seeding mixture.

Fine fescues have been receiving a lot of attention recently because of their ability to survive low maintenance environments.  Fine fescue is a category of about five different species that are often mixed together.  These species include hard fescue, slender and strong creeping red fescue, Chewings fescue, and sheep fescue.  Like perennial ryegrass, the fine fescues germinate very quickly.  Fine fescues are often the best performing species in drought trials and no-mow turf situations.  They are also adapted to shade or full sun.  For more information on fine fescues for lawns have a look at this short video: Fine fescue

Tall fescue is a coarse fescue species that has been gaining popularity due to its shade and traffic tolerance, as well as its ability to avoid drought through an extensive root system.  I find myself recommending tall fescue more and more.  Tall fescue is a bunch type grass and it can be unsightly when overseeded into existing lawns, so I generally recommend using it for new seedings or utility turf areas.  When tall fescue is greater than 75% of a stand it looks very comparable to a Kentucky bluegrass lawn, and it will require less inputs of water and fertilizer.  Tall fescue is also very shade adapted.  For more information on tall fescue have a look at this short video: Tall fescue

For a more detailed explanation of the turf species visit this short video: Grasses for Minnesota Lawns

Next week we will look at the various seed mixtures that are available on the consumer marketplace.  Stay tuned

Diagnosing Lawn Problems (50 minute recorded webinar)

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Nutrient Pollution in the Mississippi River-Twin Cities Watershed: How Outreach Efforts can be Informed by the Relationship Between Individual Water Pathway Knowledge and Lawn Maintenance Practices

By Madeline Leslie, Graduate Research Assistant

Residents of the Minneapolis-St. Paul Metropolitan area are lucky enough to have a plethora of valuable water resources on their doorsteps. Numerous lakes and streams are available for swimming, fishing, boating, and other recreational activities. However, in part due to their being located in densely populated urban areas, these bodies of water sometimes can become too polluted to be used for recreation, or even to support native aquatic life.  One major source of pollution is excess nitrogen and phosphorus running off of land into lakes, rivers, or streams. These nutrients are found in fertilizers as well as naturally attached to soil particles, and can cause large algae blooms in water bodies. The reduced water clarity and low oxygen levels that often accompany such blooms are detrimental to aquatic plant and animal life and also make for very unpleasant swimming conditions. In addition, some types of algae that form these blooms can produce toxins that are harmful to people and their pets.


Figure 1: Illustration of the relationship between impervious surfaces and surface runoff

While efforts have been made to improve water quality in the state, such as the passage of the Minnesota Phosphorus Law in 2002, many problems still exist. In 2013, the Minnesota Pollution Control Agency (MPCA) published a report[1], which found that over half the lakes assessed in the Mississippi River-Twin Cities Watershed were impaired by nutrient pollution. Which begs the question: where is all this pollution coming from? The answer is that most urban areas have an overabundance of impervious surfaces, such as streets, driveways, parking lots, etc. As demonstrated by a diagram created by the Environmental Protection Agency (EPA) in Figure 1[2], impervious surfaces do not allow rainwater to infiltrate into the ground. Rather, the runoff water drains into the storm sewer system, which in the Twin Cities is not treated, but heads directly to a lake, river, or stream.  Along with the runoff water goes any excess fertilizer or loose soil that might be in someone’s yard or driveway, and there you have it: nutrient pollution.

In urban spaces where land is divided up into numerous small parcels, controlling what runs out of each yard is very difficult, as there are multiple reasons why nutrient runoff might occur. However, most homeowners can make minor changes to the way they manage their lawns and gardens in order to reduce [Read more…]

There’s Still Time to Register for the MNLA Residential Lawn Care Forum


2014-2015 Snow Mold Trial Information is now available

Visit this link to view the latest snow mold fungicide research reports from the University of Wisconsin-Madison and Dr. Paul Koch

Spring Preemergent Applications for Crabgrass

Every year around this time I start receiving questions regarding when to apply preemergent herbicides for preventing crabgrass establishment in lawns.  Crabgrass germination is driven by soil temperatures and because of this we cannot rely on a calendar date to tell us when to apply our preemergent products.  The reality is, if we wait too long and miss the window of opportunity to apply crabgrass preventers, these products will not do much for control of crabgrass.  For this reason I like to rely on a couple of website resources that help to determine when to make these applications.  The first website that I like to use can be found here:  This is a site operated by Michigan State University and the model uses air temperature predictors to determine when to apply crabgrass preventers.  Simply select the tab “Crabgrass PRE”, enter your zip code, and the map will be created.  Below is the current map for Minnesota.  As you can see, we are just getting into the time for optimum prevention of crabgrass with preemergent herbicides.  Based on the extended forecast calling for sub-50 degree air temperatures, we still have plenty of time to get these products down. For a more detailed explanation of how to utilize this website for crabgrass prevention, see this great post from Dr. Aaron Patton at Purdue University: 



The other website that I like to use is the University of Minnesota’s Climatology Working Group Site:  [Read more…]

Lawn Care Tips For Our Early Spring Warmup (WCCO)


Regional Golf Course Report (Spring 2015)

By Matt Cavanaugh, Sam Bauer, and Dr. Brian Horgan

How quickly things can change.  Shorts and sandals are now the new theme on campus this week, which is engaging considering we experienced overnight lows below zero just last Friday.  It is always interesting to discuss the weather in Minnesota.  Snow fall last winter totaled around 70 inches of with the average being 54 inches.  As of March 6th, MSP airport has only had 27 inches of snow compared to 40 inches seen in Lexington, Kentucky this season.  It would we a crazy spring if we are to hit the averages.  According to the U.S. Drought Monitor, most of Minnesota is considered to be abnormally dry with a few counties considered to be in a moderate drought (Cass, Hubbard, Wadena, Norman, Clay, Wilkin).  Eastern North Dakota is seeing the same, but most of Wisconsin has seen adequate moisture this winter.  With all that being said, we are heading into a week that forecast highs in the 50’s and low 60’s which will initiate the plants deacclimation process, the breaking from dormancy.  Much like the shorts and sandals would suggest.

In the updates below from Superintendents around Minnesota, Eastern North Dakota and Western Wisconsin, you will notice a theme of early snow, a December and January thaw and then cold temperatures with little snow cover through February which has prompted thoughts of desiccation issues.

The general timeline looks like this for most of the region:

  • First significant snow: November 10-12.
  • Prolonged high temperatures:
    • December 11-16th with temperatures ranging from 32 to 50 during this period.
    • December 21-27th with temperatures ranging from 32 to 40 during this period.
    • January 23-29th with temperatures ranging from 32 to 44 during this period.
    • February 2015 was the 14th coldest on record statewide.

Metro Area: Roseville and Edina

Mike Manthey at Midland Hills Country Club has reported minimal snow cover of about 1-2 inches at the end of February and some ice on low spots in his fairways, but this is only a few weeks old and nothing clear or very solid.  Due to the lack of snow cover, Mike does anticipate some desiccation on higher/exposed fairways and surrounds, but little ice damage at this point.  During the two warm ups in December and January, Mike and his crew did remove water that had collected on top of the greens where he uses GreenJackets.   The other greens are covered with Excelsiors and the extended days of warmth allowed for all the water to move off or through the greens where Excelsiors are used.  Mike has been using some antidessicant products, and will consider adding more fairways and surrounds into the program next year depending on the damage seen this spring.

Brandon Schindele at Edina Country Club has also reported only about 1 inch of snow on most of the course at the end of February, but does not have any ice on the playing surfaces.  Moisture from the December and January thaws either drained off or infiltrated into the soil.  Brandon does not use any kind of cover on his greens.  Temperature sensors in greens (at 3 inches) in December were showing readings as high as 36, but have generally been in the mid to low 20’s with a low around 10.  [Read more…]

Pesticide Applicator Exam Preparation Workshop


Winter Desiccation of Turfgrass

By Maggie Reiter, Graduate Research Assistant

Major causes of turfgrass winterkill are crown hydration, direct low temperature kill, anoxic conditions under ice sheets, diseases like snow mold, and winter desiccation. These factors often work together to cause turf loss, and damage can be variable across the landscape of a golf course, sports field, or home lawn. During Minnesota winters, we don’t worry much about desiccation because we have consistent snow cover that protects the turf. This year, however, snow cover is scarce and most of Minnesota has snow accumulation below average. In some parts of Minnesota, the snowfall departure is around 20 inches below historical means (Midwest Regional Climate Center).snowfall departure from mean Feb 6 2015

Desiccation is extreme dryness that occurs when water in the plant is lost at a faster rate than water is replaced. This is a form of abiotic stress that can happen any time of the year. Symptoms of desiccation involve tissue damage that appears as browning and thinning of the turf canopy. Desiccation to the leaves can be tolerated, and usually water dehydration is not severe enough to affect the crown of the plant. But, newly-seeded or succulent plants are more susceptible to harm and death could occur. Desiccation is most harsh on elevated areas that are exposed to dry winds (Beard, 1973). Winter desiccation can injure semi-dormant turfs in frozen soil, where the plants are not able to uptake water as fast as they lose water. In Minnesota, these conditions may happen in the late winter or early spring, especially with our recent lack of snow cover.


An anti-desiccation study at the University of Minnesota Turfgrass Research, Outreach, and Education Center

There is not a great deal of research on winter desiccation injury and management. In a field setting, winter damage is often a dynamic combination of factors and the impact of each effect is difficult to discern. In a greenhouse or laboratory, desiccating conditions can be challenging to reproduce. There is a decent volume of research on turfgrass drought, but the results cannot be translated to desiccation because drought tolerance is not the same as desiccation tolerance. Drought tolerant plants are able to maintain moisture inside cells when water availability is scarce. Desiccation tolerant plants are able to survive reduced water content in cells and recuperate when water becomes available (Alpert, 2005).

A general rule of thumb is to be wary of desiccation when air temperatures are more than 20 degrees F above soil temperatures. Control measures for winter desiccation include installing wind breaks or snow fences in areas with perennial problems. Golf courses and sports fields can use protective covers and heavy sand topdressing for high-value turf. Anti-desiccant products exist for turf, ornamentals, and trees. These treatments coat plants with a sealant to prevent water loss through the leaves.

Heat waves are projected to increase in frequency and magnitude while changes in precipitation will be variable (IPCC, 2014). This climate will continue to reduce snow cover in the North Central and could foster desiccating conditions for turfgrass. Although winter desiccation is not heavily reported in Minnesota at this time, it is something to be watchful of in the future.

Literature cited

Alpert, P. 2005. The Limits and Frontiers of Desiccation-Tolerant Life. Integrative and Comparative Biology 45:685-695.

Beard, J.B. 1973. Turfgrass: Science and Culture. Prentice-Hall, Englewood Cliffs, NJ.

IPCC. 2007. Climate Change 2007: Summary for Policymakers. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, and New York, NY.

Midwest Regional Climate Center. 2014. Regional Maps: Snowfall Season-to-Date and Annual Snowfall Normals. Illinois State Water Survey, Prairie Research Institute, University of Illinois at Urbana-Champaign.