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Greens tarping:
A survival guide
Because winter is never perfect, superintendents need a protection strategy that helps their greens
survive.
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Photos courtesy of Scott Hiles |
Winter is the only season when superintendents have no immediate control over the turfgrass and its environment. Year after year, seasons of hard work get set back, if not destroyed, by the ravages of winter.
In my opinion, putting the golf course to bed to the best of our abilities is one of the most important, yet often overlooked, aspects of our profession.
The perfect winter
I wish, just once, I could enjoy the “perfect winter.” A slow hardening-off of the grass plant in late fall is followed by 18 inches of snow, which covers the ground for only 60 days, with no melt, additional snow or rain in between. This is followed by a very gradual melt over four weeks and then by warm rains and sunshine. I also win the lottery and then kiss my new bride, Pamela Anderson, goodbye on my way to my position at Augusta National (and then the alarm clock goes off).
For those of us who have survived the ravages of a not-so-perfect winter, we know how it not only affects the bottom line of the club, but also the club’s standing in the golf world. Rightly or wrongly, the superintendent’s reputation gets directly linked to the winterizing process as well.
While managing and constructing turfgrass facilities across the country, I’ve had the opportunity to see and use various methods for winterizing turfgrass systems. Every method I’ve encountered has the same basic concept: to minimize or prevent damage to the plant that can be caused by winter conditions.
The crown is my No. 1 concern when it comes to winterizing. Leaf damage is cosmetic, but crown damage can be lethal. When the ability to hop on the sprayer or aerator is out of the question, it is vital to preserve the growth point in its dormant state.
We strive to protect the crown from the following four winter-specific injuries:
• Desiccation — Loss of moisture of the crown by drying winds when the plant is in a dormant state and cannot replenish itself by root absorption of moisture
• Cold temperature kill — Crown kill associated with each turfgrass species’ genetic ability to withstand a set cold temperature
• Crown hydration — The taking in of water through the leaf blade and crown, lessening the plant’s ability to withstand freezing and causing extreme cell damage during normal freeze/thaw cycles
• Ice damage — The buildup of gaseous materials that get trapped at the crown level and become toxic to the plant
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An impermeable tarp is used to cover an entire green once the bubble sheets are laid down. In areas of high wind, the more staples, the better. |
Troubleshooting tarps
Tarping greens has proven to be the most viable and successful method to ensure a successful winterization. Utilized properly, they protect the turf from the four main injury mechanisms. More than two decades ago, Robert T. Heron, CGCS retired, was one of the earliest practitioners of tarping. He experimented with permeable (breathable) tarps in an area of the world that saw cold and wildly fluctuating temperatures with little or no snow, primarily to prevent desiccation.
Permeable tarps are still used today in areas where lack of snow cover is the main culprit causing the damage. I, unfortunately, still haven’t won the lottery and have rarely seen a winter where desiccation was my main headache, so I started looking at additional methods of covering greens.
In most areas where desiccation is a concern, there is also a great chance for low-temperature kill. Without the protection of snow cover, a cold front can wipe out turf by temperature drop alone. This is why some superintendents have abandoned permeable tarps in favor of an insulated tarping system.
These tarps are typically a nonbreathable tarp bonded or non-bonded to foam, shipping bubble wrap or some other kind of insulator. This method can work wonderfully if, again, there is no snow cover.
If an appreciable quantity of snow falls, insulated tarps can trap soil gases and cause severe damage. Ice can also seal the edges of the tarps, severely restricting the exchange of gases.
So it seems that the permeable and insulated tarp scenarios are great until a year of snow comes along.
What about those of us who are guaranteed to see winter snow and rain, often changing from week to week? Some combat the freeze/thaw cycle that is normal in the spring (and in some areas all winter long) with heavy-duty, nonbreathable tarps that keep melting snow or rain off the turf.
These work well for crown hydration, especially if the green surface was designed to shed moisture. However, like the insulators, these nonpermeable tarps also leave plants vulnerable to ice damage the moment some heavy snow cover seals the edges of the tarp.
Ice damage is most severe at moderate soil temperatures, when the crown environment is around 32 F (0 C). Develop some ice in early December, add a few months of snow cover, and a superintendent will be looking at dead turf, with or without tarps.
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A green after removal of the bubble method. Removal of the bubble method is much quicker than removing straw, allowing the crew to get busy working on the rest of the course. |
Proven tarp methods
I have used two tarping methods with great success, regardless of the winter conditions.
The first, the straw method — or “mess everywhere” method — is being used in many regions and is popular because it works.
After the golf season’s final preventive fungicide application (some may also apply a rodenticide), cover the green with a breathable tarp and secure it with staples. The tarp allows gaseous exchange and makes cleanup much easier.
Next, put down six to 12 inches of loose straw on the tarp. This straw acts as a minor insulator but, most important, creates a gaseous exchange layer that can’t be completely compressed by three feet of ice and snow, hence protecting the crown from ice damage.
The last step is to put an impermeable tarp over the whole thing to protect from crown hydration, ice formation at crown level and to act as a buffer from freezing temperatures. This last step is critical in addressing all four winter damaging scenarios. Without it, the superintendent is just managing desiccation and some minor low-temp kill.
The drawbacks? Cost: 6,000 square feet (average green size) multiplied by 19 cents (average tarp cost per square foot) equals $1,100 per tarp. Doubling that for two tarps comes to roughly $2,200 per green.
Say that after last winter’s wrath, the greens committee wants all 18 holes tarped. That’s $39,000 for tarps, plus a tractor-trailer load of straw for $1,000. So for $40,000 we can tarp our 18 holes over the next five years (typical lifespan for tarps).
Don’t forget labor. An experienced crew of at least four people can put down three tarps per day. Keep a full two weeks open if all 18 holes are to be covered. Two weeks is a luxury as we try to put the tarps down just prior to snowfall to let the plant harden off for as long as possible.
There is a spring component to this operation as well. Picking up the straw after it has been sitting all winter is laborious. The flatbed tractor-trailers that delivered those nice, tight bundles of straw have to be kept off a soft, wet golf course during the spring melt. There is a good chance that the straw, which has now magically expanded to four times the size of the original bundles, will have to sit by the side of the green sites for a week or more and be slowly taken away by smaller work vehicles. In past years, I have hired four laborers for a month for the tarp and straw removal task alone.
Finally, the straw must go somewhere, and turning it into compost takes labor, space and about a year for decomposition.
The bubble method
For the past decade, I have been helping to modify and refine another method that protects turf from all the same winter injury scenarios but is much less labor intensive, cheaper, cleaner and faster to put down and take up.
The “bubble” method involves laying down a sheet of large plastic air pockets (½ inch deep by about an inch across). They resemble bubble wrap on steroids, but have been manufactured specifically for greens tarping, not protecting glass, and are strong enough to be walked on without popping.
The sheets come in 12- by 100-foot rolls and are extremely lightweight. They can be transferred to each green with light utility vehicles and can be unrolled by one person. These sheets of air pockets, or bubbles if you like, are laid down with the air spaces down.
Pin bubble sheets to the green using typical tarp or sod staples every 30 feet or so along the length (depending on the severity of the wind that day). At the end of the green, cut the roll and continue along the adjacent portion of the green to be tarped.
Once the bubble sheets are laid down, cover the entire green with an impermeable tarp and pin it into place — the more staples the better, especially in areas of high wind. Greens covered with this system can be walked on at any time, without fear of popping bubbles or causing turf damage.
You may need to “cut in” the cover tarp to prevent water from seeping under the system during melt or freeze/thaw, and to prevent crown hydration.
Some greens, especially older ones, were built to hold moisture, not shed it. On these green complexes, water runs off mounding and the surrounding topography only to be caught in depressions or drain paths on the green itself. If this occurs on your greens, take an edger and cut a small slit in the soil along the perimeter of the green’s most vulnerable seeping points. By tucking the tarp into the “seam” and then stapling it down, you will largely prevent water from entering the system underneath the tarps.
And that’s it. I apply a light topdressing right after the final winter chemicals are applied and a few days prior to the bubble installation process.
This method addresses the four main winterization issues:
• Desiccation — Nonexistent due to the bubble tarp; the additional impermeable tarp acts as insurance.
• Cold temperature kill — Having an air pocket right at ground level acts as an insulator.
• Crown hydration — The impermeable tarp is designed to prevent melting snow or rain from entering the system. It will shed moisture.
• Ice damage — No matter how much snow, or when (or if) it falls, ice damage is eliminated.
Cost comparison
The costs for the bubble sheet system are all but identical to the straw method; however, the savings are in labor. An experienced crew can put down six bubble method tarps a day, depending on size and location. Light equipment can be used to lay it down and recover it, since the material is mostly air space. There isn’t anything lying around for weeks in the spring waiting for the turf to dry. The tasks of applying and removing are performed quickly to allow for other important things like opening preparations in the spring, and a long deserved rest in the late fall.
There is one downside: storage. The bubble material may be mostly air, but can take up room — as much as 6 feet by 30 feet for enough material to cover two greens. Because at my course benches and ball washers are going out the same time the tarps are coming in, they can alternate space in the same storage area.
To test this method at your facility, choose one green that is traditionally the worst poa-filled nuisance to winterize, try the bubble method, and turn it into your best green.
Leo Feser Award candidate
This article is eligible for the 2007 Leo Feser Award, presented annually since 1977 to the author of the best superintendent-written article published in GCM during the previous year. Superintendents receive a $300 stipend for articles. Feser Award winners receive an all-expenses-paid trip to the Golf Industry Show, where they are recognized. They also have their names engraved on a plaque permanently displayed at GCSAA headquarters.
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