Archive for the ‘Spring recovery’ Category

Submitted by: Rob Witherspoon, Director, Guelph Turfgrass Institute, robwith@uoguelph.ca

green rolling

Rolling does more than just increase green speed.

A few years ago, I was reviewing the task-scheduling program of a golf course in western Canada and came across a spring task called flintstone greens. Curiosity got the better of me and I contacted course staff to find out just what flintstoning was. It turns out that they had inherited a heavy asphalt roller from a contractor who had done work on their cart paths and found that it was ideal for smoothing out their greens after a hard Alberta winter. (Note: For those of you who didn’t wile away their youth watching Flintstones cartoons, or have wisely avoided seeing the John Goodman movie, here is a video illustrating the source of this reference https://youtu.be/2s13X66BFd8).

The practice of rolling has come and gone and come again in turf management. For many years aggressive rolling of turf areas was generally discouraged other than after seeding to firm up the seedbed or after sodding to improve sod to soil contact. In recent years, rolling has become a much more common practice on turf surfaces and specialized machines and machinery attachments have been designed for green, fairway and sports field rolling. Lawn rolling remains a lucrative spring service in the lawn care industry. Sod growers often roll in advance of harvest to increase the yield and quality of harvested sod. Let’s take a look at some points related to the role of rolling in turf management beyond seeding and sodding.

Smooth out heaving from the freeze/thaw cycle. This is the main reason we see rollers moving around residential neighbourhoods in the spring but it also applies to greens, tees, fairways and sports fields. On low-mown turf soring rolling can reduce mower scalping and improve ball roll early in the season.

Reduce localized dry spot and improve soil moisture retention. Rolling reduces the incidence of localized dry spot, increases soil moisture retention and turf root mass.

Disease Reduction. Dollar spot begins to appear around the same time as lilacs are in early to full bloom and iris are in early bloom. Both research and practical experience have shown that regular rolling results in a reduction in dollar spot severity and an extended period of protection from fungicide applications. Rolling is generally considered a superior method of dew removal and may contribute to reducing other diseases through reduced leaf wetness.

Lower the apparent height of cut without lowering the actual height of cut. On greens and fairways, turf managers claim that rolling allows them to provide faster greens and tighter lies at a higher height of cut than would be possible without rolling. Green speed measurements support this claim. Higher mowing height generally equates with healthier turf. Golf course superintendents may roll as a periodic substitute for a mow or add rolling to increase green speed especially for special events. There is also the practice of target rolling in the vicinity of the hole that increases golfer perception of green speed without rolling the entire putting surface.

Thatch reduction. When combined with sand topdressing, regular rolling is thought to reduce thatch accumulation by the grinding action of the sand particles on the thatch. The improved surface moisture retention may also facilitate the activity of thatch degrading microorganisms.

Smoothing greens and helping core holes close after aerification. Many superintendents routinely roll their greens after aerification to smooth the surface and speed up aeration hole closure. To the casual observer, rolling after aerating would seem counterintuitive as one of the reasons for aerating is to alleviate compaction and regular rolling would likely increase compaction. Recent research by Dr. Thomas Nikolai at Michigan State University indicates that rolling five times per week both improved green speed (2 feet faster after two weeks) and helped the aeration holes close faster. Soil cores taken at the end of the study showed no difference in soil compaction on the rolled versus unrolled plots.

Sustainability. As indicated above, a well-planned rolling program can be part of a money saving, pesticide reducing, sustainable turf management program by allowing higher and less frequent mowing, improving the conditions for growth and reducing disease pressure.

Rolling is not without risks. Avoid rolling during wet conditions especially on fine textured soils. Water acts as a lubricant for soil particles and rolling when the soil is wet can result in serious compaction issues. Routine rolling can also cause wear damage to turf particularly on the edge of greens with tight turning areas. Rolling should be avoided during times when the turf is under stress.

Do you flintstone your turf? What role does rolling play in your management program? Leave a reply/comment and let us know.

Further reading on rolling:

Binder, Nick. 2014. Rolling with the cool kids. Sports Turf Manager. Summer. 27(2): 1, 4-5. 30-37.

Nikolai, Thomas A. 2015. Weighing in on rolling after aerification. Golf Course Management. March. 83(3): p. 82.

Shaffer, Matthew G. 2014. Fairway management at Merion Golf Club. 2014 GCSAA Education Conference: Conference Session Presentations. p. [1-74].

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Submitted by: Rob Witherspoon, Director, Guelph Turfgrass Institute, robwith@uoguelph.ca

Turf management has come a long way from the days when a manager would stick a spade in the ground and turn up the sod to examine turf and soil conditions. While fundamental observation skills, experience and intuition are still essential components of the profession, modern day turf managers have a much greater array of tools to monitor turf systems and inform critical management decisions. Let’s take a look at three examples of instruments that may merit a place in your decision-making toolbox.

Measuring Soil Moisture

 Not that many years ago, electronic devices used to measure soil moisture rarely were seen outside of turfgrass research plots. Over the past decade, hand held TDR probes have become almost essential tools for the management of high intensity use turf areas like sports fields and putting greens. They provide soil moisture information that can be used to make irrigation decisions and audit irrigation system performance quickly and accurately. TDR stands for time domain reflectometry and works from the basic premise that the more moisture there is in a soil, the faster an electrical impulse will move through it. When selecting and using a TDR probe to manage soil moisture, it is critical to have probe lengths that measure moisture within the depth of soil containing the majority of turf roots. It is also important to realize that the measurement is only made in the vicinity of the probes – a systematic approach with multiple measurements is needed to gain an overall picture of the moisture conditions on an expanse of turf. Here is a video from TPC Sawgrass Agronomy that describes how they use their TDR probe to manage soil moisture on greens for the PGA Tour’s Players Championship.


TDR probe on turg

Fieldscout TDR probe for measuring soil moisture content.


Determining Infiltration Rates


Double ring infiltrometers are the standard tool used to measure the rate at which water enters (infiltrates) a surface like a putting green or sports field. Knowing the infiltration rate allows you to schedule irrigation more effectively to insure applied water enters the soil and does not run off to adjacent areas. It also helps you assess the impact of various cultural practices like shallow and deep tine aerating, or the application of wetting agents, on the movement of water into turf areas and through the soil profile. Double ring infiltrometers work by having two open ended cylinders that are pressed into the soil. The smaller inner cylinder contains a float with a measuring rod attached. The outer cylinder helps eliminate error from water moving laterally in the soil during the test. Water is added to both cylinders, a float and timer are used to measure the infiltration rate (cm/hour). While a number of double ring infiltrometers are available commercially, if you are handy you could easily rig up a basic infiltrometer using a couple of different sized cans, a ruler and the stopwatch on your smartphone. Here is an example of a basic double ring infiltrometer courtesy of the Food and Agriculture Organization of the United Nations.


Measuring Surface Hardness


A variety of instruments are available for testing surface hardness of which the most well known is the Clegg Hammer. This instrument measures the deceleration of a free falling weight as it hits a surface that is a measure of the ability of the surface to absorb energy from falls or balls. Surface hardness is particularly important on sports field surfaces. The greater the ability of the surface to absorb shock energy, the less of the shock energy will be absorbed by a falling athlete’s body. Monitoring surface hardness allows turf managers to make decisions regarding practices on natural fields that alleviate hardness, most notably core aeration. The device is also useful for measuring changes in the surface hardness of synthetic fields over time. Surface hardness is also a factor in the playability of many other sports turf surfaces including golf greens, cricket pitches and tennis courts. Here is a link to a short video showing a Clegg Hammer in use.


New Turf Tools?


The following two devices are examples of the expanding array of high tech instruments that may have a future role in the turf managers toolbox.

The Sphero Turf Research App that claims to be able to use a smartphone controlled ball to simultaneously measure a variety of turf surface characteristics.


Aerial drones have been in the news recently for a variety of reasons from package delivery to privacy issues. Drones have also been used to create flyover videos for golf course websites. Greensight Agronomics adds an imager and software processor that provides whole property management insights through daily flyovers of the entire course.

Do you see yourself maneuvering a remote controlled ball around your greens or flying your property with drone-mounted sensors in the future? Do you have a favourite turf tool that has not been mentioned? Let us know in the comments below.




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Submitted by Rob Witherspoon, Director Guelph Turfgrass Institute

It has been nice to feel the weather signaling the return of spring with some sunny days and above freezing temperatures following a long, frigid January and February. One of the first signs of spring at the GTI is the return of the geese feeding turf as it emerges from the snow.Geese on Snow

Reports from the field indicate that some areas have experienced ice cover since January and potential turf damage has been detected on some properties. In the Guelph area there is a thin ice layer that is mostly confined to low mown areas such as tees and putting greens.  The weather forecast calls for colder temperatures later this week with mixed precipitation and a continued warming trend the following week.

Due to the unpredictability of the weather, the decision whether or not to remove snow and ice can be difficult.  If you have not done so already, consider taking some turf plugs from problem areas that have suffered winter damage in the past. Place them in a warm, sunny window where you can keep them moist and observe any potential damage.  You can also use your nose to detect death, as damaged plugs will emit the foul, rotting odour produced by the anaerobic conditions under ice. Hopefully all of your samples smell sweet and healthy.

Snow removal is generally recommended only in situations where you have an ice layer you want to remove. If you make the decision to remove snow from greens to facilitate ice removal, consider the time and labour requirements as well as availability of proper equipment.  If you do not have previous experience with removal of snow from turf, test any equipment you are using on an out of the way site to insure it is set up properly to prevent turf damage, your operators are properly trained and collect data to help estimate how long it will take you to clear all greens. There are few experiences worse than having spring damage on greens caused by human intervention and not ice.

Ice melting can be hastened by spreading dark coloured materials on the ice surface to help transfer the sun’s heat to melt the ice. Dark fertilizers, dyed black sand and even black sunflower seeds have been used effectively.  Remove snow around greens to create drainage channels that will allow melt water to drain from the turf surface to surrounding areas. This is helpful even where ice is not an issue as melt water can pool and refreeze on green surfaces causing turf damage as the plants lose their winter hardiness during the spring thaw. Watch for the creation of “collar dams” that cause water to gather where the green surface meets the collar. You may need to carve a pathway for the melt water to move through the collar away from the green.

Please share any comments from your own experiences and observations as well as burning questions or suggestions for content to include in future ONTurf blog postings.

Rob Witherspoon, Director

Guelph Turfgrass Institute


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Soil temperature probe showing 8 degrees C at 3 cm

Soil temperature probe showing 8 degrees C at 3 cm

The resumption of turf growth after the winter has been slow. Neither sunlight nor warm temperatures have been anywhere to be found. The repercussions are widespread in the turf world. Golf courses that have winter injury have overseeded or sodded the damaged areas but cool, wet weather is delaying seed germination and sod establishment. Soil temperatures at the 3 cm depth are only at 8-9 degrees C. The optimum temperature for creeping bentgrass seed germination is closer to 16-18 degrees C. You can see we have a long way to go before we get to those soil temperatures. It will be a real exercise in patience this spring waiting to see new seedlings establish if we don’t see some sunshine and warmer temperatures soon.

Sports Turf Canada (the new Canada wide sportsturf association) is having a meeting here at the GTI and they are reporting that many municipalities have had to delay the opening of their sports fields because of wet conditions. There isn’t much relief in the long range forecast as far as warm temperatures and sunshine are concerned. We are supposed to reach a high of 18 degrees C on May 8th but then it is cooler, cloudy and wet after that.

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Patches of different shades brown turf on GTI research range

Patches of different shades brown turf on GTI research range

Well …….. maybe not fifty, but there are many dead areas of turf and the range of colour of dead or damaged turf is astounding. Also, I don’t think this post is going to be a bestseller. I guess the reason for the range is that there have been many pathways to the death of turf this spring. There is definitely dead Poa annua that died of anoxia (too many days under the ice cover), Poa annua that may have died from direct low temperature injury, or crown hydration and even in some cases perhaps desiccation, not to mention snow mould and there may even be some damaged creeping bentgrass. The colours don’t really mean anything and some of that brown turf may green up. The extent of the damage is still not clear in many areas. Let’s hope the next three days of temperatures in the double digit will help reveal the extent of the damage.

Green Kentucky bluegrassin the foreground and brown perennial rye and tall fescue in the background

Green Kentucky bluegrass and fine fescue in the foreground and brown perennial rye and tall fescue in the background

On home lawns and sportsfields, there is plenty of snow mould injury but there is also the possibility of winter injury to our most susceptible lawn and sports turf species perennial ryegrass and tall fescue.

Next steps?
Many of you are still in the assessment phase and until you have a handle of the extent of the damage it is hard to have a comprehensive plan. Covers can speed up recovery, especially if we continue to have a colder than normal spring. Companies that have been supplying covers have had them flying out of their warehouses. There have been many questions about the best type of covers or which colour is preferable for warming up soils and promoting turf seed germination. Interestingly enough, there doesn’t seem to be any good information on this. You want to be able to warm up the soil on a sunny day and prevent the heat loss from the soil on cool nights, so not sure what works best for that. At this point, the best type of cover is any one that you can lay your hands on.

Prepare damaged areas to maximize seed to soil contact. A common method on golf greens to achieve this is to core aerate, topdress, seed and then go over badly damaged areas with a Jobsaver to maximize the seed to soil contact. On home lawns and sportsfields, scalp the turf to create as much seed to soil contact as possible and either slit seed or broadcast the perennial ryegrass seed. As mentioned above, covering the greens or damaged areas of sportsfield will help speed up the germination and recovery efforts. Adding phosphorus has also been demonstrated to help speed establishment. MSU Turf blog has a good summary of actions to take to recover from winter injury at http://www.msuturf.blogspot.ca/. Even with covers, it will require some cooperation from Mother Nature to get speedy turf recovery this spring.

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