Compost calculator

Discussion in 'Planting, growing, nurturing Plants' started by Nick Ritar, Oct 9, 2007.

  1. Nick Ritar

    Nick Ritar Junior Member

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    The carbon:nitrogen maths behind making great compost has always been something that has had me stumped. So I decided to go looking for some kind of calculator online. I found one which was great, but I thought it was a bit too technical and might scare people off.

    Anyways, I hacked it to pieces and put it on our site..
    The Milkwood Compost Calculator

    I'd love some feedback to make it more useful.


    Cheers
    Nick
     
  2. pebble

    pebble Junior Member

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    Wow, that is so cool!! Thank-you, what a wonderful tool.

    Can you put up an explanation of the materials?

    eg

    - what is the difference between food waste and vegetable waste?

    - how is the newsprint counted - screwed up? flat? shredded?

    - leaves loose and compact, are they dead or green?

    etc.
     
  3. pebble

    pebble Junior Member

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    A reset button would be great too :)
     
  4. IntensiveGardener

    IntensiveGardener Junior Member

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    Nick,
    Nice looking calculator which seems to work well.
    Where did you get the ratios for the materials from?
    The ratios concerning animal manure seem misleading. What is the difference between cattle manure and dairy cow manure? Is it fresh, dryed (and pulverized) or partly dry?
    How can horse manure have a C:N of 27:1 while cow manure has 15:1?
    I'v never done any kind of tests but horse manure seems to me to be much stronger, more nitrogenous and better for heating the compost up.
    Cow and pig manures in all my old books are described as "cold" manures.

    Also, the C:N ratio is not the only thing which counts. The physical structure of the material is also very important. For instance, horse or cow manure stacked loosely in its origional state (in pats) allows plenty of air between the particals and produces a very hot temporature (60 70 degrees C)for a short period of time. If it is trodden down however (like in a traditional hot bed) it produces a medium temporature of 40 - 50 deg. for a much longer period of time.

    Personally i'v never found the ratios of the materials to be useful to know, calculate, or think about when making compost. It is very much something which you must "get a feel for".

    I usually categorize the input materials as either "green" (including manure) and "dry" and try to put twice as much dry stuff as green. Works every time :)

    Also, the lower the total C:N of the heap, the more carbon will be lost into the air. I sometimes make cold heaps (probably 50:1) which take much longer to break down but yeild more compost per unit of input.
    cheers,
    IG
     

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