A large proportion of the following is taken from my newsletter article at the end of 2009. That summer was extremely wet and cool so the pocketed greens struggled due to lack of air movement. Although they were nursed through the summer by raising height of cut, extra fertilizer & aerations etc they were slower than the other greens. Ultimately they suffered some turf loss after they were hollow core aerated right before a few days of extreme heat, where their lack of roots meant they could not survive the stress - as can be seen in this August 2009 picture of 10 green.
Just prior to the greens loosing turf the board had approved the purchase of our first fan to improve the areas, unfortunately it was not here in time to prevent the issues that year but have since proved their worth, with those greens now consistently playing the same as the others, even during some of the hottest summers recorded.
We initially started out with one fan to make sure it would work as planned - which it did. We now have five. One for 2, 4 & 10, the worst greens. The other two are used as back-ups or, if needed, on other greens (1 & 17 need them from time to time). The gas powered fans were purchased as they were substantially cheaper to buy and operate than running the power necessary across the course for electric ones. The fact that they are portable is an additional bonus as they can be moved as needed.
The fan on 2
Growing
grass is not the toughest job in the world as anyone with a lawn knows, however
growing tight, healthy, quality turf on a golf course is somewhat more
difficult especially when all the factors are considered. Climate and
weather are two of the biggest and the ones that separate all courses, even including areas throughout a course. Turf type is another factor, with some being more susceptible to stress and damage than
others, which coincidentally are actually two more factors affecting the quality
of turf. So what else does grass need? Air, light, heat, water and food are the
main ‘ingredients’ to a healthy plant, if any one is restricted in any way then
the plants health will be compromised; to what extend depends on what and how
much is restricted. So let’s look at each growth factor:
- HEAT: In this area heat is generally not a limiting factor during the growing season but in spring and fall turf covers can be used to insulate the turf (while letting it breath and get moisture) and keep it growing. There are also very expensive systems that can cool and heat the soils to maximize growth although these are usually only used in extreme environments (a good example is their use in natural grass stadiums).
- FOOD: This is the easy one to control, we fertilize as the plant needs it to meet its requirements and to help it though the different times and stresses of the year.
- LIGHT: All plants need light to photosynthesize (which it uses to create energy) and the best light available is early morning sunlight, as such it is extremely important to get as much sunlight onto the plant as early as possible in the day to ensure it has enough energy to survive. Just keep in mind how difficult it is to grow your lawn under trees, the two main reasons are lack of light and the fact the trees steal all the water.
- AIR: Air movement is another vital component both above the surface and below the surface for the roots. A perfect analogy is to think of a pocketed green (e.g. LR #4) as a sauna, the hot air has nowhere to go and just sits there making the environment humid which causes a reduction in transpiration (the plants ability to ‘sweat’ and breath which results in it not being able to cool itself down), it increases the potential for disease and algae and reduces the plants ability to fight stress. Subsurface air movement is just as important as you don’t want the roots sitting in a hot humid environment and you also have the added problem of the potential of increasing compaction (which also effects water movement)
- WATER: This is the big one as it is the source of life. During times of drought we have irrigation but for some reason Mother Nature’s irrigation is just better! Water management is one of the most important items on a golf course; too little the grass wilts, too much and you run into greater disease pressure, greater potential for compaction, algae to in excessive conditions actually ‘boiling’ the plant, so the necessity to carefully manage water is essential. The other side of water management is playability, i.e. having a fast or slow golf course.
To
a point all of the above somewhat affect each other but each are compounded by
the demands and stresses we put on the turf, examples being; low heights of cut
(e.g. our greens are mowed at less than 1/10 of an inch), cart traffic, compaction, disease, water stress and even the practice of mowing
frequently adds stress to the plant.
The fan on 4
So
now that we have a better idea of what makes grass grow, why do the pocketed greens need fans? LedgeRock has USGA spec greens which means they are designed
to drain efficiently while retaining moisture, they do this by having a perched
water table, this means they can hold water to a point, but, once that point is
reached the water literally ‘flushes’ from the system. However in wet seasons
like 2009 they do not perform as well due to the light frequent
precipitation resulting in them retaining too much moisture and not ‘flushing’
the water though (they need a lot of sustained heavy moisture to flush
effectively). In a ‘normal’ year the greens are flushed every month or so.
When a root zone has plenty of moisture the roots do not go
‘looking’ for water and get lazy, resulting in short rooting which means the
plant has less energy reserves and water uptake is lessened so it cannot endure
extended periods of stress as well. (Basically if the plant was human it would have
become lazy, unfit and out of shape). Along with roots shrinking and the
aforementioned humidity, the plant has a difficult time fighting stress. The
algae (the black areas) on the greens is a good indicator that they are wet. (The pictures below are from a few years ago). It is not too much of a concern as it is relatively easy to control chemically.
The
algae can thin out areas but the underlying factor is the fact that these
sheltered greens do not dry out fully as the air moving over them is minimal. In drier seasons those greens were able to
go two, three or more times longer without irrigation and when we water, the quantity is much less. Excessive moisture, coupled with the lack of
air movement (due to the trees and elevations) created the aforementioned
‘sauna’ effect so the plants basically sit there unable to breathe properly.
Prior to aeration in 2009 I made a presentation to the board
explaining the important of air movement (the only item I did not have any
control over). I took core samples of each greens root system and lined them
up (see the picture below). It was very obvious what greens were the bad greens as their roots were
around an inch (not good!) while the healthy greens had roots of four inches
(excellent for August, especially after a wet summer). An interesting point also was that 9 green had the next shortest roots, even though it is up high and relatively open. However it does not receive much morning sunlight so it proved that although it lacked light, and had shallow roots, the fact that it had adequate air movement meant it did not have any major turf quality issues.
Adding
the fans gives back the ability to flush the greens if needed as there is less need
to worry about adding to the humidity/moisture levels and as mentioned. I still try to minimize the amount of moisture applied to them but it is nice to have the flush available if needed. The fans also makes needle tining much more effective as there will be better air exchange with the
fresh air passing over the turf canopy.
Just how pocketed 4 & 10 greens are can be seen in these two pictures. Even if there is a strong wind felt standing on the tee, the flag will barely flutter on either!!
Another option we looked at is a Subair type
unit. These machines hook up to the drainage system and can literally suck the
moisture out of the green (they can also blow air up through the green).
Although it would help in drying out the root zone it still would not fix the sauna
problem at the surface as it would only be sucking (or blowing) rotten
humid air into (or out of) the root zone
which really would not help as much as blowing air over the surface and have the plant transpire normally. By moving air over the green surface with
the fan and flushing the green, the flushing action will draw the fresh air
with it, so while not as effective as the Subair machine, there still is a
similar benefit. These machines are useful tools and would be great in combination to the fans, but for LedgeRocks situation they were/are not a stand alone solution. Again to use the sauna analogy - If you were in a sauna and the moisture was removed it would still feel hot - if you add a fan it cools you and it feels better, if you remove the moisture and add a fan it would be very comfortable - the same applies to the rootzone.
As mentioned in this post there are sensors in a
number of greens. They have proved their worth in keeping the greens consistent and showing that the fans are working at keeping the air flowing over the greens, helping them transpire and breathe preventing large amounts of algae to take over which would result in the inconsistent surfaces.
As
ever if you have any questions on this or anything send me an email at alan@ledgerockgolf.com
