Getting the better of kikuyu and couch

Discussion in 'Planting, growing, nurturing Plants' started by Raymondo, Aug 22, 2012.

  1. Raymondo

    Raymondo Junior Member

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    I've decided to extend a garden bed that is currently about 1 m x 12 m. I'm going to extend it width-wise by about 1.8 m. There are no particular reasons for these dimensions. That's just the way it will work. I'm on very heavy clay and the area is lawn, mostly kikuyu, couch and various broad leaf things.
    In the past, I've created beds in a variety of ways:
    • Digging out the grasses and other plants, forking what's left open then mulching, a lot of back breaking work;
    • Cover area with weed mat, lift the weed mat after a year or more, fork open and mulch, a method that works well but it still takes quite a while longer before the soil becomes loose and friable, another year at least;
    • Lay down thick, and I mean thick newspaper and cover with mulch, plant into pockets of compost, fork open a year later. This works well and after a year the soil underneath is in pretty good shape, mostly. I like this method but getting enough newspaper is problematic as I don't own a car. It bothers me a little anyway because sometimes when I dig down after waiting a year the soil underneath is incredibly dry. Once forked open this is soon remedied but it nags at my conscience.
    So, for my new garden area, I'd like to try something different. It's the end of winter here and the kikuyu and couch on the surface is dead as it gets hammered by our frosts.
    I plan to simply mulch the area heavily with wood mulch (I can get it delivered cheaply) to at least 15 cm, more if I can, and see what happens. I will slit the sod into squares, roughly 30 cm x 30 cm, so that the kikuyu and couch rhizomes and stolons that are waiting underground for warmer weather will all be reasonably short. Hopefully this will mean that they will have very few nutritional reserves and so not be able to grow strongly. Whatever manages to surface through the deep mulch layer I'll spray with vinegar which will stop it photosynthesizing and feeding the rhizome.
    I will also dust with lime and blood and bone before laying the mulch. The wood mulch I get has been through a crusher so it is a mix of all sizes from dust to small broken up branches.
    Can anyone see any drawbacks to this?
     
  2. S.O.P

    S.O.P Moderator

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    The Kikuyu will die. The Couch and nut grass will pop through. From personal experience...
     
  3. pebble

    pebble Junior Member

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    Did you wet the newpaper in the older example? And by wet, I mean soak in a tub of water until saturated? I agree that cardboard/paper barriers can create problems of dryness, but there should be ways around that.

    You mulch idea sounds worth experimenting with. I would suggest doing a smaller test piece, so you don't waste the mulch (as I suspect the couch will grow through in a problematic way). It will be easier to weed with the mulch of course. I'll be interested to see what the vinegar does, if it knocks it back enough to keep it manageable.
     
  4. gardenlen

    gardenlen Group for banned users

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    g'day raymondo,

    the newspaper needs to be fairly thick we use around 30 to 40 pages thick, and overlap a good 2"s, with 40 pages that should pull nut grass up so kikuya will be taken care of and couch is easy about 20 pages will do it if couch is a single culture.

    would suggest instead of increasing width which may mean then you will need to walk on the garden make the 1.8 X 12m a new garden beside the other with a pathway could even cut the 1.8 down to 1 or 1.5 to help create path space.

    see our bale garden presentation for ideas. ask neighbours to save paper.

    https://www.lensgarden.com.au/straw_bale_garden.htm

    len
     
  5. purplepear

    purplepear Junior Member

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    put down plenty of lime and chook poo (your blood and bone will do great) before your newspaper, raymondo And be sure to water it in well. This attracts worms to the area and they consume the weakened and dying grass. Then if you get a bit pop up again you just bung on some more paper and be more persistent than they.
    If you can not get enough paper for 30 to 40 pages thick then you should be content with what you have and you will find that much less is more than enough.
    Most of your worries will be from the surrounding grass coming back in and a good spaded edge (well maintained) will keep them at bay to a great degree.
     
  6. Raymondo

    Raymondo Junior Member

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    Whenever I've used newspaper, I have soaked it well. It is always sopping wet when laid. I lay it thick, entire newspapers thick, and well-overlapped, because of couch. Even then, a few strands always seem to manage to get through but it's easily removed. All beds are well delineated by a narrow trench to prevent grass encroachment from 'outside'. The new area I'm doing, because it will only be mulch and not paper, will have a trench one spade's width wide. Paths will be marked by using a thin layer of other material, probably grass clippings, to delineate them, no problems there. I suspect the couch will reappear but vinegar is pretty good at couch control. I've used it before on a fence line.
    I have the time of year in my favour because, as I mentioned, the above ground parts of both the couch and kikuyu are dead at the moment. The underground parts have been living off reserves for the entire winter so should be fairly weak. I don't think I would attempt this during the growing season. As SOP points out, the kikuyu should pose no problem. Luckily, we don't have nutgrass here. It will be the couch that might undo me. Well, I feel more confident now. Thanks for the comments. I'll post the results in a few months.
     
  7. mischief

    mischief Senior Member

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    I have an area with couch grass that I thought I had got rid of.
    I noticed that nothing is growing under a trailer and was going to use some corro iron on blocks to try to create the same effect..except I had tidied up and its under Stuff.
    So instead, I have 3 hoops over that part of the yard and have weedmat over it, completely covering it.
    I'm going to leave it there all summer.
    be nice if I could figure out what else to use this little patch for while its covered.
     
  8. Raymondo

    Raymondo Junior Member

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    Okay, experiment over. Didn't work. Both the couch and kikuyu, but especially the couch, came through no problem at all. I must say that I'm surprised that the kikuyu came through. Oh well, I'll be scraping off the mulch and either putting down newspaper and mulching over that or putting down weedmat and waiting till spring. Nothing ventured ... as they say.
     

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