Digesting Living Thatch

Discussion in 'Turf Renovation' started by Smallaxe, Feb 25, 2012.

  1. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    I've posted this article before, but we never really got this far into it...

    "Core aerification, followed by topdressing are two methods that will generally correct the reasons thatch is accumulating. Core aerifying machines will pull up small soil cores to the surface that are left there to act like topdressing. The holes created help solve problems such as compaction or poor drainage. Topdressing is simply adding a thin layer(1/8 to 1/4 inch) of compatible soil over the thatch, which adds microorganisms to help in breakdown."

    This article doesn't talk about molasses/sugars to increase the activity of microorganisms that way, and certainly compost will do even more.

    What would happen to the material that is broken down and would it benefit the soil in any way?

    Is it cheaper and more beneficial than mechanical dethatching and removal of debris?
  2. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 13,178

    You are right to be a bit skeptical, Small. These ideas help to sell aerifying machines. There is already plenty of air in River City. So why don't they call them thatch machines?

    My lawn has never been aerified. After 28 years it does not seem to harbor any more insects or disease than anywhere else.
    "Topdressing...adds microorganisms to help in breakdown." Really...I have never thought my lawn was deficient in microorganisms.

    Does anybody have any side by side comparisons of molasses and untreated control? Photos? Thatch depth measurements?

    I am not starting a controversy--just stirring the pot.
  3. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    Side by side comparisons would be tough, because you'd have to stop the cultural practices, in order to accomplish anything... Just aeration or Just molasses/compost or doing both...

    I don't grow living thatch either so it will be difficult to set up 3 plots in someone else's lawn. Soil and air temperatures w/adequate moisture, is going to be critical for these tests to work uniformly...

    The key to the living thatch problem is that the suface roots are growing upward, into the mulch and stems, becuz there is always so much water and N there. Things of course die and tangle faster than they can be digested, hence the need for thatch machines.
    Try to rip open the layer so water and NPK can go down, then the roots grow down after it, like they're supposed to.

    Would using molasses, to quickly increase the populations of microbes, to quickly break down as much mulch as possible, when the conditions are right; work better than ripping into it with thatch machines??
  4. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    U of I has always steered away from organic practice recommendations for thatch control as there is no real data to support the claims of organic products to break down the thatch. We discussed this issue in the Master Gardners course.

    There are other organic practices also that aren't mentioned due to liability reasons that U of I doesn't want to be responsible for.

    Take for instance Milky Spore. It is now proven that it isn't as effective as once thought to control grubs in the lawn. Gluten as a pre-em is another one that might get put on the chopping block.

    Now, you talk to some of the professors off the record and they might say differently.

    As experience, I believe their recommendation to be good facts. The newer subdivisions in our area are stripped beyond any good layer of soil. Most lawns are set on-top of hard clay with little to no organic matter, including the lack of earth-worms in the lawn to help aerate the soil.

    I also feel in these situations mechanical aeration is necessary to break the Cat-Ion exchange layer that inhibits the natural breakdown of thatch and also nutrient binding.

    And to respond to Riggle, U of I also recommends aerating only in the Fall when it is the most beneficial, so to say their data is to promote mechanical means of compaction release and thatch control isn't necessarily true.

  5. Smallaxe

    Smallaxe LawnSite Fanatic
    Messages: 10,082

    I will also steer away from organic practice recommendations and likewise steer away from organic products...

    For a heavy clay dirt as you describe in recent construction lawns, wouldn't it make more sense to till in sandy loams, or even compost alone, to break up CE sites?
    Just becuz it results in mixing OM into the soil, doesn't make make sandy loam an organic product... does it?

    Dirt doesn't become Soil, until there is enough OM in it, to overcome its mineral properties enough to, reasonably, grow something, IMO... :)
  6. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776

    I think you are hitting on a good point. What is the true definition of organic products or organic practices.

    Even in the MG course we discussed adding compost, loam and other products, but again I feel that U of I only "recommends" the minimum and in general, just basic soil fits the bill.

    From what I remember, even the professors who taught each section of the course left each situation to interpretation. The main point being is that cultural practices should always be evaluated first, then the best course of action can be taken. Ultimately they were trying to do everything they could to stay away from mechanical and chemical means to treat the lawn and garden.

    And just to add to my original post also about aerating. Aerations became popular in the late 70's and early 80's due to grub control applications that were killing of the earthworm population causing thatch problems. It's just unfortunate that it has become a "recommendation" by lots of commercial companies saying that it's a must in order to have a healthy lawn, when it's far from the truth.

  7. Exact Rototilling

    Exact Rototilling LawnSite Fanatic
    Messages: 5,377

    Okay this got a bit long winded and there is some repeated points.


    Last season I started to use dry livestock molasses [$20 a bag] to help control my own “inherited” thatch layer of 3/4 of an inch. Did it do anything yet? Not sure but I will only be using it during warmer weather to get the maximum effect from it. Decomposition is always higher when temps are higher. In another thread I have picks of the dismal impact of my own Lawn Solutions aerator plus a Bluebird [even worse results] rental rolling tine aerator. The reciprocating Plugr due to the impact speed of the tines and the pop effect will successfully and consistently punch through the thatch layer and deliver the plug near the top of the grass blades. Advantage of this is the top dress effect. The rolling tine units in that instance simply lacked the pop effect and speed of reciprocating tines punching through a tight thatch layer.

    I did at least 6-7 total aerations passes with my Plugr 850 on my lawn last year. To get the same effect [if a rolling tine unit could or can effectively punch through the thatch layer reliably] would have to be in the range of 11 – 12+ passes.

    Late summer I did one of the aerations and mowed the next day side discharge with Oregon G6 gators and the dirt cloud was tremendous. Organic debris was truly liberated from the dirt thatch balls separated from the soil thanks to the High lift G6 gators. That was the first time I had ever mowed cores with the G6 blades. I only wish I had taken some pics and video of those thatch balls blowing around the property. The neighbor was standing there trying to figure out what the deal was. I actually broke my front window in the process since I wasn’t running the discharge deflector.

    Fact. Aeration cures thatch where the plug is pulled if in fact the tines are able to punch and cut through the thatch layer. What happens here is rolling tines are often plugged with gravel and no core is produced. The Plugr style tines are better able to clear them selves due to the plunging speed and pop effect etc. Problem is a single rolling tine pass is dismal at best on a percentage of surface area.

    When the thatch in the core/plug is liberated from the dirt an free to be broken down by exposure to the elements, mower and the wind neighbors yard....it can disappear or break down get cut up more by mower blades etc. A double pass of my Plugr 850 can only be exceeded in percentage of soil volume “if the plugs are equal in length” by “4” passes with a rolling tine machine.

    Mowing over “more than a double pass from a Plugr 800” is truly a dreadful extremely dirty experience.

    The dirt top dress effect from the plugs has to help thatch break down. Rolling tine aerators simply fail in plug count and the ability to pop plugs near the top of the grass in most instances.

    From a practical standpoint running fresh sharp edges flail blades down into the true thatch layer will get rid of the thatch quickly but will result in a tremendous amount of debris and haul off.

    Personally I rather offer a client a double Plugr pass 3 to 4 times a year than be stuck with a true flail blade de thatch. And give them a volume discount to keep the cost reasonable. Many claim to get 3X the mow rate for aeration. So I guess if a homeowner can find someone to flail blade all their thatch out for cheap that would be most cost effective.

    Those front of the ZTR 3 rows of tines are less effective than the spinning Bluebird/Husky spring tine bar mounted on a power rake or seeder. That is NOT dethatching!

    Buying bags of molasses @ $20 a bag...... I’m not sure if the molasses products are cost effective when compared to the benefit of reciprocating aeration with a Plugr or a Ryan 28.

    All those Plugr passes from last season have dramatically faded the fairy ring in my lawn as well. Maybe it was in part due to 2 applications of molasses....?
  8. White Gardens

    White Gardens LawnSite Fanatic
    Messages: 6,776


    Instead of mowing the plugs you could also consider using a power rake at a shallow dept in order to bust up the plugs without the mess of just power raking, or just mowing the plugs.

  9. Exact Rototilling

    Exact Rototilling LawnSite Fanatic
    Messages: 5,377

    I've spring tine raked plugs as well but you're pretty much standings over the dirt cloud continuously with little escape. At least with side discharge there is some escaping the debris. Next time I plan to try the G6 gators but with the mulch plate installed and reduced rpm on first pass.
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  10. Exact Rototilling

    Exact Rototilling LawnSite Fanatic
    Messages: 5,377

    It has been my premise that if a lawn has basically zero thatch and a very high night crawler population core aeration is of little or no benefit. Is this not correct? Case in point my dad’s lawn has no real thatch layer and is extremely high in night crawlers.

    This also begs the question. My own lawn 3/4” [inherited] thatch layer has very very few active night crawlers....so how do I jump start a healthy population of night crawlers?

    Are there any online sources to explain the finer details of the Cat-Ion exchange layer? I’m assuming it is an abbreviated term...?

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