Aerification... Taking one step back to take two steps forward

     Some of you out there may wonder why golf courses seem to always be destroying their greens, tees, and sometimes fairways.  I'v heard it a million times, "You just got the greens looking wonderful and then you go out and punch a bunch of huge holes and throw down way too much sand and it ruins them!!!"  Rest assured golf course superintendents (and myself included) all want their golf course to play perfect each and every day for a long time to come.  It is that exact reason that we aerate; we want the playing conditions to constantly improve.  Sometimes you have to take one step back to move forward to reach your goal. 

 

This is the main reason that we aerate a few times each year...

     You can see the different striations just under the grass.  See that darker brown layer just under the grass?   That is the main reason that the tee boxes at Wildflower golf course took such a hit when it finally decided to warm up this year.  With that much thatch, it is inevitable that your grass is going to become a weak stand sooner than later.  This cut was from #6 Main tee box, and if you've golfed out at Wildflower, you probably noticed how dry #6 looked. 

      These are the main reasons to alleviate thatch in grass:

        1)  When thatch dries out, it becomes HYDROPHOBIC. hydro=water   phobic= repels

        2)  Thatch that stays wet is a perfect breeding ground for fungi

        3)  Excessive thatch can lead to scalping and "puffy" stands of turf

        4)  Elevated levels of thatch actually take the crown (the actively growing part of the plant) up off the soil profile and can lead to pulling out of the crowns and actually rooting just in the thatch.  This problem leads to turf that is easily damaged by mowing, walking and divots taken by normal golf. 

         There are many more reasons to hate thatch, but you do need a small amount (usually around .25 inches) for a healthy stand of grass.  Thatch, although mostly talked about in a negative way, buffers the crowns from temperature extremes and when thatch is broken down on a microbial scale, it adds much needed food for the surrounding plants.  Thatch gets detrimental when it is allowed to build up past the range of normal acceptance. 

       When were talking about thatch becoming hydrophobic, I mean it literally is scared of water.  No matter how much you pour onto the grass, it won't work into the soil because the thatch is so tight and becomes water repellent when it dries out.  Look up professor Larry Stowell, PACE Turf... This guy is amazing!!!!  He has a pretty good YouTube video on why us superintendents aerate.  The use of wetting agents will help alleviate some of the hydrophobicity of the thatch, but if you don't want to add more chemicals to your grass, the only option is aeration.

      The very basis of aerification is simple,  you punch a hole in the ground, fill it with sand, and the magic starts.  Usually taking what's called a "core" from the turf opens up the root zone to let much needed oxygen, water and growing media (sand) into the holes left from pulling the core out of the ground.  This mix of porous sand mixing into the usually organic-matter rich soil also aids the microbes in breaking down even more thatch.  Microbes need oxygen to do their job, just like we all do to survive.  Without oxygen, or in an anaerobic state, means that the microbes aren't doing their job, and then the thatch starts to build up once again.  This is the major reason that we have to continually disturb the soil profile to add oxygen to aid the microbes in breaking down the organic matter.  Another benefit of pulling out cores and filling the holes with sand is that grass roots will take the path of least resistance in search of water and nutrients.  Imagine trying to stick a pencil into compacted clay and good black dirt.  Wouldn't you think that it would be easier to stick that same pencil into sand, and wouldn't that same pencil go deeper and require less work to get deeper?  Now, I know most of us can push a little harder on the pencil than the grass roots can, but aerification holes provide the grass with an easy route down to find more water and more nutrients. 

 

   The grass will fill in, the sand will work it's way into the thatch layer, and the grass will be healthier for all the work we do to destory a beautifully rolling green.

    As I'm writing this, we are finishing up punching the back 9 tees at Wildflower.  Greens will be aerated later this summer, and I look forward to hearing all the complaints of the golfers who didn't get a chance to read my lecture on why I do what I do!!!  We're not the only golf course that aerifies, and I'm certain that my crew loathes the job board when it says aerification just as much as golfers!

 

Keep Hacking-

  Aaron

 

PS-  I welcome comments/complaints!  Please feel free to leave a comment and Ill do my best to get back to you in a timely manner on here!