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St Augustine Topdressing Question

Discussion in 'Turf Renovation' started by southernprecision, May 20, 2010.

  1. southernprecision

    southernprecision LawnSite Member
    Messages: 19

    We have a St Augustine lawn that has a extremely thick thatch layer. About three weeks ago the customer had us come in a rake out all the dead stolons and matted dead portions. We also lowered the mower to about an inch or so. Afterwards we filled in the bare spots with "filtered" topsoil and lightly spread topsoil across the areas that were not badly affected. Problems is that was three weeks ago and the turf has yet begin to spread. On top of that she now has leaf spot despite swearing she is watering at most twice a week. We can treat the fungus but was wondering if it could have come in on the topsoil? Also should we fertilize once we get rid of the fungus? Really stumped. Thanks for any suggestions.
  2. southernprecision

    southernprecision LawnSite Member
    Messages: 19

    HAHAHAAHA...everybody wants to view...nobody wants to step up and answer!! I dont feel quite so bad!!
  3. rob7233

    rob7233 LawnSite Senior Member
    Messages: 873

    Well, this post had so many different things going on, I had to quote it for reference. First a couple questions: which variety of St. Augustine are we dealing with? Was the lawn truly thatchy or spongy? The cause for a spongy lawns is generally too much fertilizer and water over time. The best approach to that is to cut back on the fert/water to recommended levels and to spread sand as top dressing to work it's way down to roots. Now please keep in mind too much fert/water with increased temps can clearly set up an environment for fungus.

    Now you speak of matted down areas and dead grass/stolons. What exactly did you use to get that out? Got any before pictures? So now we are speaking of this raked out, thatchy, matted down, possibly fungused and stressed lawn that you cut down to about one inch. By doing so, you cut all the leaf area (food/energy producing and disease fighting ability) out of the plant, not to mention adding the possibility of an fungus issue. The cutting height may be an somewhat an exception depending on the variety of the turf. Cutting to one inch creates an issue of increased envirotranspiration(water loss). A stressed lawn will require much more water to recover from your possible procedures along with adding to any inability to deal with an fungus issue that might be already present.

    Sounds to me, you might have been too aggressive on this lawn. Please don't fertilize since it isn't "lawn medicine" and could greatly contribute to an already present fungus problem. All this, might be some reasons you are seeing an "inability to thrive". Now fungicides won't bring back already damaged areas but provide a "shield of sorts" against further spread. Even at a curative rate, it still take time for the uptake and assimilation of the chemical.

    Again, you have so many issues going on here with a lot of unanswered questions. This might be the reason no one yet has tried to tackle your posted question. Additionally, you never really accurately identified why/how the lawn got the way it was prior to you starting or what was needed to correctly address those issues. Go ahead and answer the questions I listed and we'll go from there....

    "HAHAHAAHA...everybody wants to view...nobody wants to step up and answer!! I dont feel quite so bad!!" :confused:
    Last edited: May 24, 2010
  4. ArTurf

    ArTurf LawnSite Platinum Member
    Male, from Ark
    Messages: 4,383

    Were you seeing any green matter before? St Aug may have suffered some winter kill due to colder than normal winter. Mowing to 1" in St Aug was a mistake that really stressed out a lawn that was already suffering from what you say. I would try some fert when you think it is safe to do so, just not overly aggressive with a lot of fast release nitrogen.
  5. fl-landscapes

    fl-landscapes LawnSite Silver Member
    Messages: 2,542

    didnt read the replies yet so maybe this has been said. First off dead stolons on top isnt thatch its dead grass. Thatch is below the grass above the soil and roots. I personally would never scalp st augustine. In my opinion if you had a thatch problem you should have verti-cut and top dressed. Then adress to your customer why they have a thatch problem.....lover fertilizing over watering. If its not thatch and it's dead grass sod cut it out and re-sod.
  6. Landscape Poet

    Landscape Poet LawnSite Gold Member
    Messages: 3,638

    Lowering the blades on SA is not a good idea - rob covered this and I agree with his input on this issue and many other inputs he suggested . I mow all SA at 4 inches. IMO it allows the turf to help with natural weed prevention..keeps the turf healthier and allows the soil to stay more moist, which aids in preventing certain pest such as chinch bugs.

    Different fungus types - the fungus spores are actually present in the soil and can remain there I think for 3 years or longer - so yes if it was present in the topsoil that you applied. Not that that was the cause - fungus spread in many ways such as walking, mowing equipment and even the wind.

    About you customer watering only twice a week. It is not how much she is watering as it is WHEN she is watering and how much water is being applied.
    She should water in the early morning hours and not in the evenings as to allow the turf to dry out quicker.
    Not sure about your environment but down here the SA does just fine in most situations if you set the irrigation system to delever between 1/2 and 3/4 of inch per application with 2 applications a week, resulting with roughly 1 inch of water per week. If she/he waters in the evening, especially during summer when the humidity is still high in the evening, she is creating a perfect environment. Add a little excess N and watch out.

    As rob stated do NOT add fertilizer while the fungus is present. After visable signs of fungus are gone, you can try to fert again but beware that if fungus is present it is like throwing lighter fuel on a BBQ. Would be best to start with a low N fertilizer IMO and one which has a very high slow release N.

    IMO your customer would be best served by getting a soil any. Research has show that having critical micro and macro elements such as Mg, Mn, Cu and B can dramatically increase the chances of many diseases including many fungus.

    About treating the fungus - I would only do this if the lawn is a high risk for extensive damage from the fungus. applying a fungicide will most likely create a void as they tend to wipe out the good guys too. As ITC Bill says there is nothing that mother nature hates more than a void. Guess which will replace the void quicker beneficial or harmful?

    Good luck
  7. Landscape Poet

    Landscape Poet LawnSite Gold Member
    Messages: 3,638

    Might I suggest corn meal as your fertilizer too.......will help feed the good microbes allowing them strength to fight in the lawn, it has been show to help create a beneficial bacteria that helps prevent and fight many lawn fungus. Will do this without adding excess N. Do not be fooled by the analysis on the bag either, it will green very well if applied at 20lbs per K.

    Also do not stress about the turf not spreading like crazy yet, some SA lawns down here are still struggling coming out of the winter we had. They are just now starting to get going really well and we are in our third week of the temps being in the 90's.

    Again good luck
  8. fl-landscapes

    fl-landscapes LawnSite Silver Member
    Messages: 2,542

    wow typing fast spelling horrific! address and lower not lover:laugh:
  9. southernprecision

    southernprecision LawnSite Member
    Messages: 19

    Thanks everyone...your knowledge and input is greatly appreciated. Let me see if I can answer a few questions. It is not a lawn that we have been caring for very long, maybe 3 services max. Lawn had a mix of heavy thatch and was obviously very thick. Not so much spongy though. My assumption was in fact winterkill due to stolons not being attached to the soil. It was because of this reason that no premergent was applied by our company. As far as mowing height, I screwed up in explanation, we lowered the blades an inch below our normal height to 2 or 2.5 inches. Sorry for that...wording makes a huge difference.. As for the fungus,,,I have driven by twice this week and once last week (morning) and irrigation was at full blast...how long? no clue. I will address with her today. My plans are to allow the heritage to work then apply 17-0-5 @ 2.25 per k. Thanks for the cornmeal idea. I will research and let you know how it goes. Thanks again.
  10. RAlmaroad

    RAlmaroad LawnSite Silver Member
    from SC
    Messages: 2,253

    We've had winter killback on the St. Augustine on the coast. Some strains of it are just not tough enough. Palmetto seems to be the best overall for winter. Maybe you should try to use a 1:1 fertilize with Nitrogen and Potassium are used at 1lb/K monthly. This would help promote the stolon growth.

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