Winter Kill Woes

The extended ice cover and constant freeze-thaw cycles have taken its toll on our predominately Poa annua greens. In particular, greens on holes 9, 11, 12, 13, and 17 have the most extensive damage with roughly 1/4-1/2 of the green affected. This blog post hopes to help the membership understand the different types of winter kill and why winter kill occurs. Lastly, we will go over our short-term and long-term goals of minimizing our risk of winter kill.

There are many factors that encourage winter kill to occur they include: grass species, lack of drainage, over abundance of trees near the putting surfaces, and weather. Poa annua is much more susceptible to winter kill than any other grass. At Ridgeway, we have about 80-90% Poa annua on our greens while many other courses have much higher populations of bentgrass. This is why courses in close proximity many have winter kill while others may not. That being said, there are also differing varieties of Poa annua. Poa annua var. annua is a truly annual species of grass while Poa annua var. reptans is a perennial that seeds out in spring and lives on as a perennial. The truly annual species of Poa is obviously weaker and more susceptible to stress. Bentgrasses are much hardier against winter kill and are one of the main reasons golf courses renovate greens to make it the dominate species.

Lack of drainage is a huge factor that affects winter kill because melting snow and water can more easily get trapped on the greens surface. Because it gets trapped, subsequent cold temperatures freeze the trapped water and form a nice layer of ice. Ice, as I will mention later is detrimental to turfgrasses especially Poa annua. Improving drainage will greatly help in minimizing turf loss due to ice formation and crown hydration problems.

Trees that border or in close proximity to the putting surface can increase the likely hood of winter kill. Spruce trees and other conifers are especially detrimental because of the dense shade it casts over the putting surfaces during the short days of winter. Conifers that are to the south and south-east are problematic because the greens are virtually covered in shade for the entire day in mid-winter. Shade inhibits the sun from melting any ice cover and keeps the temperatures colder than that of greens in full sun. Selectively removing trees particularly south of the putting surfaces is a smart idea to allow for more sunlight in winter months.

The most important factor and one that Superintendents have yet to control, is the weather. Some years are better than others for winter kill and some areas get hit hard while others are left unscathed. For instance, the Milwaukee-Chicago area was hit hard by winter kill last year, however just north of the Milwaukee area was seemingly unaffected at all. This year at Ridgeway we received a lot of snow and a lot of melting. This can be problematic because melting snow pools up and refreezes over and over again. This type of scenario usually produces ice cover that sits on the green for extended periods of time. Having talked to several superintendents they have also experienced winter kill this spring. Golf courses with more Poa annua and poor drainage are more affected this year than courses with higher populations of bentgrass and better drainage. Other forms of weather can also be problematic. Winter weather that produces no snow and bitter cold is problematic, it causes dessication. Other scenarios are times when mid-winter thaws are followed by extreme temperature drops that shock turfgrass plants. And in some cases regardless turf species, drainage, and trees the weather causes extensive winter kill to the point nothing could have been done to prevent it.

There are many types of winter-kill, they are as follows: extended ice cover, crown hydration, direct temperature kill, desiccation, and snow mold diseases. In a year where winter kill is present anyone of these factors can cause turf death. Again Poa annua is the most susceptible to all of these forms of winter-kill while bentgrass is almost rarely affected.

Snow mold diseases affect turf over winter and are usually not an issue for Ridgeway because we spray tees, greens and fairways with the proper fungicides that protect the plants over winter. Both bentgrasses and Poa annua are highly susceptible to snow mold diseases thus requiring the same fungicides for proper control.

Desiccation is winter kill that is associated with very cold winters with very little to no snow cover. The plant is then exposed to cold temperatures and high winds. This has an effect on the turf similar to putting your hand on dry ice. There are many ways to protect turfgrass plants from desiccation, one way is by putting out covers over the putting surfaces that help protect the plants from cold and wind. The other method is by applying moderate amounts of sand that act as a blanket and protect the crown of the plants from extreme cold. Both methods are successful against desiccation, we chose to cover our greens, tees and approaches with sand. We have enough covers to use on 8 of our greens at Ridgeway, by putting sand over our greens we were able to cover all 18 greens instead of just 8. The other side benefit is that we are able to incorporate the excess sand into our greens profile. Increasing the amount of sand in our greens profile is one of our higher priorities that our staff and greens committee feel is very important. Burying greens with sand in late fall is a common practice that many golf courses use to protect the plant overwinter while adding sand to their greens profile. A couple of months ago there was a blog post about this exact topic and reading it will give you more insight on why sand and not covers.

Direct temperature kill is another form of winter kill that happens typically when warm mid winter thaws leave the plant unprotected and large swings in temperature shock the plant causing it to die. This happens usually on exposed turf in a short time frame when temperatures go from lets say 45-50 degrees to sub-zero in a matter of hours. Usually sand and covers do an excellent job of protecting the greens from this type of injury. However, in extreme cases nothing can be done to prevent this type of turf loss. Again Poa annua is most susceptible to this type of turf loss.

Extended ice cover and crown hydration are the last two forms of winter injury that I would like to discuss because they are main reasons for turf loss at Ridgeway this year. Continual snows and several thaws left solid ice cover for many days on our Poa greens. Initially, we were able to remove ice with black sand and milograinte (see recent blog post). Poa annua greens can only with stand 30-60 days of ice cover before carbon dioxide reaches toxic levels. The plant then dies from a lack of gas exchange a term called anoxia. Bentgrass can survive 90-120 days of ice before it has issues with an excess of carbon dioxide. As you can see Poa annua is much weaker and can succumb to winter kill due to ice cover way before bentgrass. In fact, it is rare to see bentgrass affected by ice because 90+ days of ice cover is very, very uncommon. Crown hydration is somewhat related to ice cover because can be caused by poor greens drainage. Crown hydration is when melting snow or rain water is taken in by the plant and a sudden change in air temperature causes the plants to burst. This would be similar to taking a plastic soda bottle at room temperature and putting it in your freezer, after a few hours the bottle bursts. This is a good analogy of what happens with crown hydration and turfgrasses. Once again Poa annua is more susceptible to this type of winter injury. Bentgrasses are more resilient and can withstand this type of injury better than Poa. This scenario was the case in late March when the golf course was water logged and free of snow. A wet late season snow storm dumped 10" of new snow. Standing water underneath was exposed to 4 days in a row of temperatures in the single digits. This scenario in combination with excess ice cover early in the winter provided a situation in which the weak Poa annua was unable to fight against winter kill.

Here is an article about crown hydration:

http://archive.lib.msu.edu/tic/mitgc/article/1995259.pdf

Now that we have discussed why winter kill occurs and the different types of winter kill we can go over what we can do to minimize winter kill on our greens at Ridgeway. In the past few greens and grounds committee meetings we have discussed the importance of drainage on the golf course. In fact, the committee and staff made it our number one goal going forward. Improving drainage on greens will minimize water pooling up in low spots and curtail the chances of ice and crown hydration issues. Our long-term plan is to drain #4, 6. 9. 11. 12. 13. 16 and 17 greens to allow water to move into the profile better. With this new drainage we will be able to put large drains with a cup cutter hole that will act as a drain like you have in a bath tub. Also increasing the amount of sand in our greens profile will also improve drainage and is one of the reasons we chose to sand our greens over using covers. In conjunction with improving drainage we have been selectively cutting trees around putting surfaces so shade does not interfere with the flow of water in winter. By implementing these methods we should see an improvement long-term with regards to winter injury. In fact most of the issues concerning the golf course have been or are being addressed in our 2011 maintenance plan and the new long-range plan.

For more information about ice and winter injury look at past blog posts about some of the issues we encountered last winter. There you can also find professional articles related to ice and other forms of winter kill. Also in the next couple of days look for blog posts the show what steps are being taken to bring the greens back from winter damage.

Ice Revisited

The latest article by Bob Vavrek, the USGA senior agronomist for our region, takes a look at some of the potential ice problems this spring. About a month ago, I wrote about ice that was present on our greens and what measures we took to combat this situation. Vavrek's piece goes a little more in depth but hits many of the main points that my post does . . . it may also help to revisit my post or read if you have not done so already.

Link to Bob Vavrek's article:

http://www.usga.org/course_care/regional_updates/regional_reports/northcentral/The-Dicey,-Icy-Decision---February-2011/

Master Plan

Here is an interesting essay written by golf course architect Tom Doak and his associate Bruce Hepner. Mr. Doak is one of the most accomplished golf course architects in the field today, boasting many courses that rank in the top 100 in the world and US. While being a great golf course architect he has also written many books on the subject, which are also worthy of reading. Mr. Doak and his associates at Renaissance Golf Design also renovate/restore older golf courses. In fact, they have been involved with work at clubs in Wisconsin like North Shore Golf Club, Milwaukee Country Club and Bluemound Country Club. The purpose for giving the link to his essay is to point out how to make changes to Ridgeway without having to pay the large fees associated with having a master plan. The essay outlines what subtle but important changes can be done without the need to hire an architect. Fortunately for us we have been or will be doing all the things that are outlined in the essay. Enjoy!

http://www.renaissancegolf.com/selected_essays/restoring_your_home_course/

Ice

The new year brought us the gift of ice this winter as an early thaw with temperatures in the upper 40's and low 50's created considerable snow melt. Immediately following the warm temperatures, cold nights around zero trapped and froze the water that had been melting during the end of December. The result was a nice layer of black ice on many of our putting surfaces. Some greens where completely clear of ice and some where completely covered in ice. #11, #12, #13, and #16 greens where one-hundred percent covered in ice. Greens like #5 and #10 had no ice at all.

What does this mean? Ice cover on a green can cause considerable damage if left on the putting surface for long periods of time. The duration of ice cover, before damage will occur, depends on the species of grass that is under the ice. Ridgeway Country Club's greens are predominately (80% +) Poa annua and the duration of ice cover before damage will occur can vary from 30-60 days depending on the what research article you read. Bentgrass however, can withstand 90 and in some cases 120 days of ice cover. Ice cover produces a scenario where gas exchange is greatly hindered and the grass plant suffocates to death. Anoxia is the term used to describe this phenomenon and is basically turf death due to a lack of oxygen. In order to minimize turf loss due to anoxia, ice cover must be removed to allow the grass plant to breath and receive the oxygen it needs to live.

The above pictures are of the greens after the snow was removed and only the ice was showing.

These last two pictures are after black sand and milogranite was applied to the surface of the ice. The last picture shows melting of the ice after black sand and milorgranite was applied.

Ice on Ridgeway's greens formed on New Year's day and last week we made an effort to remove snow and expose ice to the sun. Remember that ice can cause damage with 30-60 days of coverage on Poa annua greens. Since we where at 20+ days an effort was made to speed up the melting process. Our crew went out and surveyed the greens to see how much of every green was covered in ice. Then snow was removed on only the portions of the greens that had ice cover. After the removal of snow, milogranite (a black organic fertilizer) and black sand where applied directly over the top of the ice. The black color helped absorb the suns heat making ice melt happen quicker. Unfortunately Wednesday and Thursday last week were not sunny as had been predicted by meteorologist but Friday saw a few hours of sun which melted 75-80% of the putting surfaces. Now, only time will tell if any damage to the putting surfaces occurred, more than likely minimal damage occurred because we where able to remove a large percentage of the ice to allow proper gas exchange. My only concern now is the remaining ice in the low spots of some of our greens. An effort to melt this ice will be made sooner than later depending on the weather forecast.

Many important factors must be taken into account when removing or melting ice from greens. One factor is the temperature that is being forcasted immediately following the removal of snow and ice. If snow and ice is removed with cold temperatures or high winds, this can cause other forms of winter injury due to desiccation or direct temperature kill. Snow is a good insulator from the elements, which is why we only removed as much snow as needed to melt ice. A few snow storms since Friday have helped cover the greens to keep them insulated against the wind and cold. Another factor to consider is, what turf species predominates our putting surfaces and what action if any is needed to protect your greens. Because we have a large Poa annua population it is imperative to get the ice off before the 30-60 day window. If we would have mostly bentgrass more than likely no action would be taken because 90 + days of ice cover is needed for problems to arise.

People have asked: why not just use greens covers and we won't have ice? In my experience green covers do little to combat ice coverage. Simply put, if we had green covers we would have ice on top of covers and would have to go through the same process as I explained up above. Green covers work well for other types of winter injury, that being said so does burying greens in a nice layer of sand. We chose to bury our putting surfaces in sand because we could protect all 18 greens, tees, and approaches from dessication. Conversely, we only have enough covers to protect about 8 greens. Applying a nice layer of sand has some nice side benefits as stated by Bob Vavrek in an article written in the USGA green section record, titled "There Is No Time Like The Present."

Vavrek states this about late fall topdressing,

"Late fall topdressing is the poor man’s cover that provides turf fairly good protection from wind desiccation. The often-overlooked benefit of sanding greens before winter is thatch management. Root growth on greens will continue through fall and into winter until the ground freezes. The sand that buffers turf from the damaging effects of winter wind also will help dilute the late fall/early spring organic matter that is recycled into the greens. In effect, pre-winter topdressing provides an effective bridge between the last coring or topdressing operation of fall, and the initial coring or topdressing operation of the following spring. Just how much sand to apply before winter will vary from course to course. Greens maintained at higher heights of cut can accommodate more sand than greens at short heights of cut. When in doubt, it makes more sense to err on the light side of late fall topdressing."

The decision to go with a layer of sand instead of covers was one that was well thought out and took into account many important factors. Because we are in the process of aggressively removing thatch and organic matter from our putting surfaces, the winter topdressing in lieu of covering 8 greens was a no brainer.

One thing research is conclusive on, is that greens that have poor internal drainage, are mostly Poa annua, and/or have trees (especially spruce trees) planted closely to the putting surface are more apt to see winter injury. By improving our sand profile, improving drainage, and removing selected trees around greens we can help combat some of our winter injury woes.

Here are some other articles that discusses ice and other related winter injury.

http://www.usga.org/course_care/green_section_record/2007/jan_feb/Snow-Way/

http://turf.lib.msu.edu/1980s/1980/800101.pdf

http://turf.lib.msu.edu/1990s/1994/940517.pdf

http://ptrc.oldscollege.ca/summaries_plantstress.html

Reading Material

Dustin Riley, the golf course superintendent at Oconomowoc Country Club, wrote this article recently in Golf Course Industry Magazine discussing the importance and reliance of venting, particularly in stressful times of the year. As many of you know it is a practice that we routinely utilize to "help out" our turfgrass plants in the heat of the summer. For those who do not understand the practice of venting and its benefits can read this article to find out more information.


http://www.golfcourseindustry.com/gie-111-cover-story-dustins-inferno.aspx

Frost delays

In the spring and fall of the year in Northeast Wisconsin, frost early in the morning is a common phenomenon. Golfers are oftentimes delayed from playing due to frost. Delays are very inconvenient for the golfer, but it is important for the health of the golf course to respect these delays.

Why is it important for the superintendent to suspend play until the frost is gone?

Grass plants are made up of mostly water, this water turns into very fragile crystals of ice. Simply walking on turf with frost can cause damage, particularly on a green where the height of cut is around 1/8". Walking on a grass plant with frost is like breaking glass or cracking an egg.

Why not just throw the sprinklers on to get rid of the frost?

This method can work however many factors must be considered before turning on overhead irrigation. What is the air temperature? . . . What is the soil temperature? . . . What temperature is the irrigation water? . . . How heavy is the frost that is covering the grass? I have seen where turning on overhead irrigation cause more frost and in turn makes the delay much longer !!

As a maintenance staff we try to keep the proshop as informed as possible regarding the length of the delay. Keep in mind this is only a guess, and hourly updates usually keep the membership/proshop up to date as to the length of the delay. Usually foretees has the frost delay on it so people who are at home are aware that there tee time may be moved back till they get the "all clear."

Thank you and your cooperation in adhering to these policies is greatly appreciated !!

Here is a informational link to frost delays:

www.gcsaa.org/solutions/facts/frost.aspx

What are the white lines?

Many people have been inquiring about the white lines that are present around many of the greens and approaches. These lines are marking where either the approach is being bumped out, or where the green is being enlarged. Why do this?? Overtime many of the mowing lines have been altered by daily maintenance practices. Essentially the greens and approaches have shrunk overtime. This is very common on older golf courses because the operator(s) who is mowing cheats a little bit so that he/she doesn't scalp the edge of the green or approach. Consistently doing this results in the shrinkage of greens and other fine turf areas.

There are several different ways to enlarge and restore lost areas that have shrunk. You can sod the areas to bring them back to there original location, which has it pluses and minuses. Sodding can be done very effectively, especially if the remaining turf species is not either Poa annua or Bentgrass. By sodding, the unwanted turf species are eliminated and a mixture of Bent/Poa is present. Sodding, however, is very labor intensive and usually good nursery stock is needed to expand these areas. Cost being an important factor and the limited amount of quality nursery sod, make this option less viable for us in this transition. The other solution to restore lost playing surfaces is to slowly lower the height of cut over the period of several weeks then match it to the existing height. This is very effective particularly in areas that are still predominantly Bentgrass or Poa annua. Many of the areas targeted for enlargement are still predominantly Bent/Poa mixture. This allows us to slowly lower the height and make a gradual transition over the period of a few months.

With both methods problems can arise! When sodding areas turf does not always take to the transplant. Its much like a human getting an organ transplant, sometimes your body rejects the newly transplanted organ. Turfgrasses are really no different and some areas of sod take better than others. Pitfalls also arise when "mowing down" areas; the turf make not like the lower height and may thin out or die in spots. By starting now we give the turf better conditions to help make this transition/transplant easier and less stressful on the plant. Also coming out of winter we can prepare these areas to make it through the coming summer. Continually topdressing and aerating these "mow downs" will also help make these areas blend in better overtime. Topdressing will smooth these areas and aerating will help remove any thatch/organic matter that may potentially make the transition fail.

By bringing back the original location of our greens, approaches, and fairways the golf course plays the way it was intended too. Another reason to move are greens back to there original size it to give us more options with hole locations. The greens at Ridgeway are fairly small averaging 4,200 square feet a green. Restoring more putting surface will allow for more flexibility with course set-up in the future and less wear on turfgrass plants.