The Secret to Good Lawns, Good Soil

Dr. Kevin W. Frank
Assoc. Professor & Extension Turf Specialist

I recently rode along with a landscape services provider to visit what he called some difficult properties.  On these visits I usually only bring a couple items, camera and soil probe.  The first home lawn we visited was indeed difficult.  Upon arriving at the site first impressions were a lawn that was thinned, stressed, and not surviving the recent heat spell very well.  Walking the lawn it quickly became evident that soil moisture was not the problem, well actually it was the problem, too much water.  To this point it’s been a very wet summer and any irrigation a homeowner might be adding when it’s not needed can easily push a lawn from adequately watered to soaking wet.  As I started to probe the soil in various parts of the lawn it became obvious the underlying soil was not helping the lawn.  In most areas no matter how hard I leaned on the probe I could only force it into the soil 2-3 inches.  This was the typical example of turf trying to grow on compacted clay.  Sometimes on visits there’s a moment of truth, on this visit it was looking at the neighbors picture perfect patch of green next to this struggling lawn. 

When I pushed the soil probe into the neighbors lawn the probe went down about 10 inches easily.  Bottom line, growing turf on compacted, high clay content soils is a challenge.  As the story was slowly revealed, the area of the lawn that was really struggling was heavily trafficked and compacted following a recent pool and deck installation.  Following construction, it was not clear if any efforts were made to break up the compacted soil before sodding, my soil probe would say no.  Best solution of course would be to start over, bring in 4-6 inches topsoil and sod or reseed the lawn.  For most homeowners this is an unrealistic solution based on cost and pain.  The less disruptive solution is to put the lawn on a regular core aerification and fertilization program and to monitor watering closely to avoid a saturated, waterlogged soil. 

The second visit I wouldn’t have found on my own.  My inclination when traveling to a neighborhood to visit a lawn is to look for the bad lawn and stop there.  On this visit we drove right by the bad lawn and stopped at a lawn that from curbside appeared to have few problems.  As we walked the lawn in silence I found some small areas with dollar spot and a couple areas with necrotic ring spot that appeared to have been successfully managed to avoid turf loss or the sunken ring.  Both of these I considered minor blemishes considering the hot stretch of weather we just went through.  Finally I basically raised my hands and said, what’s the deal here?  My host for the day replied with, they just don’t think it’s as good as the neighbors, not as uniformly green.  There were some patches of fine fescue in the lawn that some could find objectionable if they want a perfect Kentucky bluegrass lawn but it seems unnecessary to me to start this lawn over or kill off those patches.  We’ll write this one off to unrealistically high expectations.   

High quality home lawn with equally high homeowner expectations.

Turfgrass Disease and Stress Update

Dr. J.M. Vargas, Jr.

Michigan State University

Well summer has finally arrived with a vengeance! Up until now other than some dollar spot and Waitea patch it has been a dull summer for diseases. Now with the arrival of the warm weather brown patch, Pythium blight, crown rot anthracnose, foliar anthracnose and summer patch are all becoming a problem. The real key to the development of these diseases has been the warm night time temperatures. These diseases become problems when the night time temperatures stay above 68 F. Of course the humidity has also helped these diseases to become a problem.  It is important to remember where these diseases are occurring the fungus is already inside the plant and it is necessary to use a systemic fungicide to stop the advance of the fungus inside the plant.  Contacts fungicide may prevent any new infection but they will do nothing to prevent the fungus in the plant from causing further damage.  Many areas in the state have received a lot of rain this spring and summer and consequently the turf has poorly developed root systems from oxygen continually being pushed out of the root zone.  The reason for mentioning this is soon the cooler weather will return and with it will be cool days in the 70’s with low humidity.  On these days, and especially if the wind is blowing the turf will begin to wilt rapidly and die if irrigation is not applied quickly. So in other words, don’t relax and let your guard down just because cooler weather has returned.

Brown patch on a putting green.

What can I do about Japanese beetles landing on our golfers?

Dr. David Smitley
Michigan State University

The next 4 weeks (mid July to mid August) will be the busiest for Japanese beetles on the golf course.  Because their activity level is temperature dependent, they are the most active on hot sunny days.  They will continue to feed on trees and shrubs, and lay eggs through late July and August, but the onslaught will taper in late August, and very few will be left by October 1^st.   Meanwhile, golf course superintendents are dealing with some unhappy golfers, especially in places where Japanese beetle has recently become a problem and the golfers are not used to them.  At first people may think they could bite or sting, or they just do not like bugs of any kind.   Golfers should be told two things: that Japanese beetle has recently spread into northern Michigan, and that they are completely harmless to people.  Superintendents can minimize the nuisance factor to golfers by spraying tees, greens, and a buffer strip or 20’ surrounding tees and greens with Sevin (carbaryl), Tempo (cyfluthrin)  or Decathlon (cyfluthrin).  Any trees or shrubs that beetles are feeding on near tees and greens should also be sprayed.   You can also pull most of the beetles away from tees and greens by placing a Japanese beetle trap 100 – 200’  away from each tee and green.  This will attract beetles to the trap and away from the tees and greens.  Don’t place the traps too close to tees or greens because they can pull beetles in from as much as an 1/8 mile away.  The traps need to be emptied every 2 – 3 days by dumping the beetle into a bucket with a few inches of soapy water in it.  Another strategy is to plan ahead for the next year by treating the larval stage of Japanese beetle, C-shaped white grubs, in July to prevent turf damage in the fall and next spring, and to reduce the number of beetles that will emerge next summer.   Merit, Arena, Aloft,  Meridian, and many new products containing imidacloprid, all work very well when applied in July.  This will not help with the  beetles that are out now, but it will reduce the number of  beetles you have next year.  As you could probably guess, treating all of the turf on the golf course (wall to wall) has the biggest impact on how many beetles emerge next year.   However, treating just the irrigated turfgrass also has a big impact because the females prefer to lay their eggs in moist soil under turfgrass. 

Of greater concern to most superintendents is the turf damage that can be caused by the white grubs feeding on the turf roots in the fairway.  Grub damage to fairways appears as patches of thin, yellow or dead turf in late September, October, and May.   On fairways, more than 5 grubs per square foot can cause a problem.  Even worse is the damage caused by skunks or raccoons when they tear-up turf to eat grubs.  An application of one of the insecticides listed above, before August 15^th, will prevent grub, raccoon or skunk damage in the fall and next spring.  Be sure to irrigate just before and just after applying an insecticide for grubs with ½” to 1.0” of water to move the insecticide into the soil.  There is a high correlation of the incidence of insecticide failure to control grubs with failure to irrigate immediately after application. 

Japanese beetle feeding.

At MSU we are doing something else to help prevent damage from Japanese beetle.  With funding from the Michigan Turfgrass Foundation, I have introduced a disease-causing pathogen of Japanese beetle into Michigan.  It is called Ovavesicula popilliae, and it only effects Japanese beetle.  This is a naturally occurring pathogen and cannot be purchased.   At the Michigan Turfgrass Field Day at the Hancock Turfgrass Research Center at MSU on Wednesday, August 14^th, we will be providing a small bag of infected Japanese beetle adults to each participant.  See the Michigan Turfgrass Foundation Website for information on how to register for the field day -  http://www.michiganturfgrass.org/

Summer Turfgrass Establishment

Kevin W. Frank, Aaron Hathaway, and Thomas A. Nikolai
Michigan State University

Summer is certainly not the ideal time to establish cool-season turfgrasses due to high temperatures, long day length, disease pressure, and especially weed competition.  The optimum growing temperatures for cool-season turfgrasses are in the range from 60 to 75 °F, occasionally during some of our warmer stretches of weather the night time temperatures might not even fall within this range.  Long day length or more hours of sunlight, results in more hours in the day for drying the soil.  Maintaining that delicate balance of soil moisture between too wet, and too dry is more challenging during the summer due to the extended drying period.  Periods of high temperature, relative humidity, and heavy rains or overwatering can also make new seedings subject to devastating diseases such as pythium blight.  Finally, weed competition from summer annuals such as crabgrass, goosegrass and broadleaf bandits such as purslane, knotweed, clover, and prostrate spurge can quickly take over a new establishment in the summer if herbicides are not used.  If you're still interested in establishing in the summer keep on reading, if not, wait for the optimum establishment time of late August and early September.


Weed Control

Weed control during summer establishment is definitely one of the keys to success or failure.  Tupersan (a.i. siduron) is the traditional stand-by for controlling weeds during seeded turfgrass establishment.  Tenacity (a.i. mesotrione) can also be used safely at the time of seeding.  There are also combination products with quinclorac and carfentrazone that provide control of broadleaf weeds in addition to crabgrass and goosegrass. Mesotrione and siduron can be applied on the day of seeding of cool season turfgrasses for control of crabgrass during establishment. Quinclorac + carfentrazone (SquareOne) can be applied early after turfgrass seeding (7 days after emergence) to control crabgrass and broadleaves.

Always read, understand, and follow the label directions. Mention or exclusion of specific products does not represent an endorsement or condemnation of any product by Michigan State University.  

Weed competition during summer establishment.

Fertilizer at Seeding

At the time of seeding, apply a starter fertilizer at a rate of 1 lb. N/1000 sq. ft. to help those young seedlings get established.   A starter fertilizer is a fertilizer with a N:P₂O₅ ratio similar to 1:1 or 1:1.5.  Under the phosphorus restrictions in place in Michigan, starter fertilizer is still allowed for turfgrass establishment.  The maximum amount of phosphorus that can be applied in a single application is 1.5 lbs. P₂O₅/1000 ft.² with a yearly maximum of 2.5 lbs. P₂O₅/1000 ft.².  If you have the time to take a soil test, follow the soil test recommendations for establishment.  Homeowners can purchase a soil testing kit from the MSUE bookstore (http://www.bookstore.msue.msu.edu/product/soil-test-kit-selfmailer-1116.cfm).  More information on soil testing can be found at www.msusoiltest.com. 

Mulches for Moisture Retention

Make sure to keep the seeded area moist throughout establishment. In many cases this may require watering several times a day. A good mulch cover will help the area stay moist so the site may be watered less frequently. Water lightly when irrigating, there is no need to see water puddling or running off the site.