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winklebe

smallest size for testing compost?

19 years ago

just wonder if anyone has ever looked into doing small "batches of compost" kind of as tests to see how to mix tings up to get a good hot pile.

so my question is how small can I make a mix of stuff like 1 gallon or so and see how long to heat up and how long it stays hot. To build some references for myself.

I am not cooncerned about complete composting of the material as I will just throw the stuff in the bin after i do the "tests".

thanks

Comments (20)

  • 19 years ago
    last modified: 11 years ago

    I think that the majority feel that it takes 3'X 3'X 3' (one cubic yard) to have enough mass for a good hot pile. Then you would have to have somewhere in the ball park of the proper ratio of greens to browns, moisture and air.

    Things could be different in a compost tumbler or in the one gallon that you mention, but I do not think that they would necessarily be representative of what you should build a pile with. For instance, cleaning out the gutters of my house and sheds, I find really great lookin black stuff where collected pollen in the spring, or leaves in the fall have composted pretty quickly. I just put it into a wheel barrow and dump it into my compost pile, have not tried any around plants so I do not know how good it would be, but I think that it would be pretty one dimensional.
    Just my thoughts.
    Bill P.

  • 19 years ago
    last modified: 11 years ago

    While small piles of organic matter will eventually become soething resembling compost it is volume that provides the bacteria that do the digesting a place to work. As BillP indicates a 3 x 3 x 3 pile is about the smallest volume that will really allow those bacteria to work well.
    Since there has been tons of research into composting that all tell you that a ratio of 30 parts Carbon to 1 part Nitrogen or a pile of material that is 3 parts vegetable waste (ie high carbon material) to 1 part manure (ie high Nitrogen material) is the optimal mixture why would further research into how to mix things up to attain a hot pile be necesssary. What you really need is to learn the art of composting since the science is already there and it is the art that determines whether your compost pile gets hot or not. Did you get enough, or maybe too much, moisture in that mix.

  • 19 years ago
    last modified: 11 years ago

    Kimmsr, you say vegetable waste is carbon, can you tell me what you think vegetable waste is, list the items. When I think of vegetable waste I think of apple cores, banana peels, potato pealings and the link. If I am right I think those are all greens, right? Carbons would be leaves, paper, cardboard, straw.
    Just trying to clear my brain on this, and make it clear for all.
    I have the mantis twin tumbler and I find I can turn out some pretty nice looking compost and have gotten and maintained a temp of 150 for a couple weeks, with it being over 100 for a few weeks, slowly dropping off till it stays cool. Time to dump at that point.
    Sandy

  • 19 years ago
    last modified: 11 years ago

    brdldystlu, I agree vegitable waste is green.

    Secondly, Kimmsr, as posted before If "throw it in there and hope I am close" mentality was good enough then why even bother composting in the first place the science has been done and it is called miracle grow. Secondly if people are willing to take "Science" as the end of all inquiry then efficiencies may never be achieved.

    I spend many hours in my yard and would like to know that the things I am doing are correct for what I have. So if I was to have a huge pile of something and wanted to get the right amount of coffee grounds to get the big pile going then why not work a test in a one gallon size first and extrapolate the proper amount to add to the pile.

    The main reason I first started to think of this idea was to take a byproduct of my salt water aquarium called "skimmate" it is the proteins and waste that get removed from the water I produce about 1 cup per day and would like to know how effective of a Nitrogen source this is so I was going to mix varying mixtures of paper and skimmate and see how well it works.

    I appreciate the comments and concerns and I agree that a 3x3x3 is the min for total composting. Just wonder how well a 1 gallon size would work to inform the composter if there mix is right. Adds some efficiency to the process since building and rebuilding a pile can be very time consuming.

  • 19 years ago
    last modified: 11 years ago

    Sandy, I do not always agree with kimmsr, but do not see all that much wrong with what he posted. Perhaps it is a matter of semantics or where your mind is at the time of posting. Could be that dried corn stalks, dead tomato plants etc. could be browns. I agree that most all veggie waste coming from the kitchen and a lot of that of the plants coming from the garden are greens, especially if you pull them right away when they have quit producing, but not always.

    My guess would be that the slimey gunk from an aquarium would probably be a "green", my question would be if it came from a salt water aquarium, would there be enough salt to hurt things. In fact, would there be enough of that produced to even affect a 3 X 3 X 3 pile to any significant degree, much less a larger one, unless one has a mighty big aquarium.

    I would think that the best way to satisfy winklebe's mind on a one gallon basis, would be to try it. However, I am still of the opinion that there are still some dynamics of the size and diversity of the pile, mass etc. that come into play that would not be present in the one gallon experiment.
    Just my thoughts.
    Bill P.

  • 19 years ago
    last modified: 11 years ago

    one could no doubt make a gallon size pile that would heat somewhat if it was carefully assembled, including a good dose of a range of decomposer microbes, but the heating would be over so fast it might not even be noticed, and regardless, it wouldn't really tell you anything about how a full size pile would act because air and moisture have a very large effect, and it would be difficult to get those just right in such a small container .... besides, it's really the rapid and prolonged reproduction and growth of the microbes that generate the heat

    as someone who has been composting {{gwi:257816}} for years, I can assure you that all food waste could be classed as "green", tho the fact is that food waste generally has a C:N ratio in the range of 15-20:1, and a good mix of it is nearly perfect by itself except for the fact that it's invariably too wet and needs some structure, which is easily provided with some coarse carbon rich material like sawdust

    Bill

  • 19 years ago
    last modified: 11 years ago

    My 2 cents on this. If you try to find an optimal mixture using a 1 gallon bucket, you'll find an optimal mixture for a 1 gallon bucket. It will probably have no relevance to an actual compost bin or pile.

    If you want to try something like this, by all means do so, but I don't think you should expect it to have any meaning for composting in situations other than the ones you test.

  • 19 years ago
    last modified: 11 years ago

    Skimmate..awww that wonderful smell. My two saltwater tanks have protein skimmers. My friend drilled a hole in his and it drains into a five gallon bucket with a lid on it. But he just chucks it down the toilet.

    I wonder if we could send this protein shake to get tested like a soil sample to see if it has too much salt in it??
    It would definetely be a green.

    This compost wacko just saw a light pop in his head.... zoo aquariums collect hundreds of gallons of this stuff a week...My buddies girlfriend works with the hippos at a zoo close by.....

  • 19 years ago
    last modified: 11 years ago

    Vegetable waste equals tree leaves, straw, dried garden debris as well as the vegetable waste from your kitchen. Vegetable waste is any plant residue that once grew in the soil. Vegetable waste could be anything that is not animal or mineral. You limit your self too much if all you think of vegetable waste is what comes out of the kitchen.
    Sir Albert Howard formulated the specifics as practiced for centuries by the people around Indore, India and that has been studied by many people in many places and you can find the science behind composting at Cornell Composting as well as Organic Gardening magiazine and the Rodale Institute and many other places connected to universities.

  • 19 years ago
    last modified: 11 years ago

    you limit yourself by limiting your language kimmsr - plants and vegetables are 2 different creatures, and while plant waste may include vegetable waste, vegetable waste ncluding plant waste is not generally the case ... the term you're looking for may be vegatative, but the primary definition of "vegetable" is the edible part of a plant ... doubt many here eat leaves or straw ... not to mention wood chips :)

    Bill

  • 19 years ago
    last modified: 11 years ago

    To be quite honest- I think people worry too much. You're not formulating paint or pottery glaze, or making a soup or beer that relies on a specifics.

    Chop/shred it up. Get it moist. Add enough greens and browns. Pile it high and have enough volume.

    I really can't think of much more that's important in making it work.

  • 19 years ago
    last modified: 11 years ago

    The size of the pile has to do with the surface to volume ratio. You want less surface that will cool off and more volume where the heat is produced.

    As for 30:1- I never really calculate. This has to do with feeding microbes, however, not a chemical reaction so I suspect it's not very variable. I do make a pile a bit more green if I want heat in the winter, though I can't say with authority that it helps.

  • 19 years ago
    last modified: 11 years ago

    I know that lots of posters here are very interested in the theory of composting and that for them the process is an activity with its own merits. But I think that for many gardeners and householders composting has a more multifacetted role. I compost because it deals with waste created by me and my family in as environmentally sound a way as possible, keeps my personal area of land tidy and is good for my garden. Therefore what goes into it is governed not by the needs of the perfect compost pile but by what is available. For me the idea of buying in or driving to collect material for composting and fretting over ratios always has a worrying tinge of losing the point. I think Pablo might be on my side.

  • 19 years ago
    last modified: 11 years ago

    Flora- I agree with you. I do, however, pick up compostables that others are chucking out near work etc (like bags of leaves). Just the composting part is fun, and this stuff feeds my whole 1/2 acre of grass/weeds/gardens (the other 1.5 acres is woods). I know folks on small lots that intensively grow a lot of food- they need to find a way to supplement the OM from their yards (and they've found free sources to do it).

    I also have many doubts about those who insist that we really need a wide variety of materials in a pile.

    When I read about miracle organic fertilizers with 50 or 70 micronutrients I have to cringe. Plants mine nutrient and incorporate it. Guess what a plant really needs to live? The stuff that it ends up incorporating. How many micronutrients are in just plain old compost? How many are really going to enhance plant growth over what you get (they're only needed in MICRO quantities).

    Hmmm- seems that common yard waste and plants are just gathering up all the good stuff that you need already. My normal veggie scraps and oak leaf piles do great for everything I grow. If your soil has some sort of deficiency or problem that compost isn't handling (and more compost doesn't cure it), then target that. Buying the miracle shotgun cure at a premium price is "feel good", but I don't think it does any better.

  • 19 years ago
    last modified: 11 years ago

    actually Pablo, you'd be suprised at the range of micros that are in any plant material, and especially food waste - or maybe you wouldn't :)

    there are important micronutrients of one type or another that are lacking in most soils - here in the PNW, boron can be deficient, and while not much is needed it can have a pronounced effect on blooming and fruiting - boron is high in many of the foods we eat, so even a bit of kitchen waste in the compost can make up any lack in your soil .... folks that don't compost might well need those 70 things in miracle-grow, or a few anyway, and the high number of "growth affecting" factors, and variability in soils, are the reasons that variety in a compost pile is desireable, as well as the fact that lots of nutrients and micros interact, so it's helpful to have some balance - compost is way more than NPK and carbon

    and Vance - 30:1 is the "ideal", much higher N will be more likely to go anaerobic sooner, and will usually be too wet [fresh manure, fresh grass clippings, veg scrap, etc] where higher C can easily be too dry, and there may not be enough N for the bacteria to work optimally - oxygen and moisture are the other 2 indispensible factors, and the whole "mix" is to allow the microbial decomposers to thrive - they use N [like protein] to reproduce and grow, C [like carbohydrates] to work hard, and too little air or water they die off, too wet they drown

    so the 30:1 is a bit of a simplification, but it's a good "rule of thumb" - 20:1 can be made to work with management, and 40 or 50:1 can work too, but it will be slower and won't attain or retain the heat - 80 or 100:1 and you make "leaf mold" instead of "compost", because the decomposers that will work in that much C are mostly fungi

    Bill

  • 19 years ago
    last modified: 11 years ago

    The 30:1 ratio is not "a bit of a simplification" nor a "good rule of thumb" but is the optimal ratio of Carbon to Nitrogen that if the moisture level is about right will get your material digested the fastest. As Bill points out a ratio of 20:1 or 50:1 will allow digestion to take place but much more slowly.
    Excess water in the pile will displace air and lack of air will also slow down the digestion, so among the things that need to be looked at when your compost is not performing as expected beside the N is the air/water ratio.
    My webster indicates that vegetative and vegetable are fairly synonymous and can be used, with very few exceptions, interchangably.

  • 19 years ago
    last modified: 11 years ago

    I love composting stuff, but if I actually weighed (the ratio is by weight) and integrated the nitrogen and carbon content of my compostables as I added them... well, I'd have to postpone a lot of other stuff I'd like to do.

    I don't calculate at all, and my compost gets really hot and finishes pretty quickly just eyeballin' what I put in.

    Soils may or may not lack micronutrients, but I'm guessing that compost generally doesn't. That was my point- compost fixes most nutrient issues. I don't think that my garden would grow very well in my un-amended yard soil because of nutrient and pH issues. Compost seems to fix it all for me (YMMV- as I said- some places are woefully low in some component).

    "actually Pablo, you'd be suprised at the range of micros that are in any plant material, and especially food waste - or maybe you wouldn't :) "

    Not at all- i keep saying that we're teeming with micros waiting for us to die (MWUHAHahahaaa...)

  • 19 years ago
    last modified: 11 years ago

    flora_uk:
    I agree with part of what you said..."For me the idea of buying in or driving to collect material for composting and fretting over ratios always has a worrying tinge of losing the point."

    Composting can be for more than one reason. Composting to reduce the load on our local landfills and to keep nutrients on our property is one thing. Composting to improve the overall quality of our garden soil is another. Buying alfalfa pellets to achieve the right C/N ratio is counterproductive if all I am trying to do is reduce my curbside waste. However, I am interested in creating a significant quantity of compost to improve the condition of my sandy Florida soil, so I may get better results from my garden. Leaf mold would work, but as this is my first year collecting leaves, I am impatient and do not want to wait 1-3 years for the results. So I have gathered more leaves than I think I need this year. Some of them are getting the extra nitrogen from alfalfa pellets (and some with 26-2-1), so I can get the end result this year. The rest will be left as-is and will be ready for use as leaf mold in the future. In the following years I will be able to have leaf mold, as well as mixing stored fall leaves and summer greens for compost.

    And I have to say this, my F-150 gets horrible gas milage, but it gets better milage than the big truck that drives around our neighborhood each Friday. I have brought home enough leaves to fill half of one of those trucks. I'll bet I have burned less gas and done less damage to our roads that that truck would have. So collecting a neighbors leaves, in my opinion, is a net gain for society. Convincing my neighbors to not put it out there in the first place would be better, but what I do is a close second.

    Everyone:
    I guess I understand it enough. 30:1, damp like a sponge, turned regular for oxygen, and it all works out quick and efficient. O, C, N and water are all present in proper ratios. Do this with a 3x3x3 pile and the optimal temperature part works out also. So is the problem with a 20:1, ratio too much heat? And too little heat with a 50:1 ratio? It would then seem that temperature control would allow for variations on the C/N ratio. Right? If the microbes are made up of N and water, and consume O and C to live, with heat and compost as a byproduct, then more N and water means more C and O is consumed, resulting in even more heat. With the wrong C/N ratio, there is either too much or too little mass (the C) to dissipate the heat, resulting in a non-optimum temperature range. At 30:1, as the carbon is processed the mass stays the same, so as long as O keeps coming, the temp and microbe activity stays steady. Once all of the carbon is processed, they die due to lack of food. At 20:1 (assuming O and water are non-limiting factors) there are too many microbes thriving, there is not enough space for the heat to spread to, so the microbes cook themselves. At 50:1, the microbes living do not heat up the pile enough to create the perfect temperature for the right microbes to thrive. Does this explanation sound reasonable?

    kimmsr:
    According to Britannica, via google,
    "Vegetable: In the broadest sense, all plant life and plant products (vegetable matter); in common, narrow usage, the fresh edible portion of herbaceous plants (roots, stems, leaves, flowers, or fruit), either eaten fresh or prepared in some way."

    Columbia University Press (also via google) says:
    "vegetable: term originally used for any plant, now the name for many food plants, most of them annuals, and for their edible parts."

    I think you are correct in your assertion that vegetable and vegetative are interchangeable in many cases. You were talking over me when you used vegetative and vegetable interchangeably. Well, you were, now I know. I always appreciate learning something new. However, in the context of discussing C/N ratios, greens and browns, I think it is confusing. I think vegetative= browns vegetable= greens is the most effective in communicating with the largest number of people. According to the above definitions, current, common usage agrees with this.

    Thanks.

  • 19 years ago
    last modified: 11 years ago

    As long as you have a rough idea of the C:N ratio of various materials, or you pile those materials in the 6 inches of vegetable waste with 2 inches of manure, you need not weigh or carefully calulate the actual C:N ratio. As long as it is close, and you have just enough but not too much moisture, your compost will generate lots of heat and cook sufficiently well that it will become finished compost, even a pile of leaves (C:N ration of 40:1 to 80:1) will eventually become compost. They are mostly very slow to get there because mostly there is not sufficient moisture, or maybe not sufficient volume on the forest floor.