I and my colleague faced an unexpected problem during the mixing of a new compost ingredient today. We found an unexpected and unknown material left by a previous farm intern. We recognize the ingredient by the type of bag holding it, but apparently someone filled this bag with something other than what it normally holds. Please see the photo:

Unknown ingredient

Another close-up image after spending half-day in a compost bin (slightly dissolved and contaminated with other compost ingredients) enter image description here

Does anyone recognize what is it? It looks like some kind of hamster bedding to me, but I am not sure. Also, it does not have the smell of cat litter from my olfactory memory. It is easily crushed into a powdery substance.

  • It looks like some kind of hamster bedding to me but I am not sure.
    – y chung
    Oct 20, 2016 at 15:23
  • Vaguely resembles pelletized grain (feed) I've fed to young dairy calves.
    – GardenerJ
    Oct 20, 2016 at 15:34
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    Thanks for the information! Our farm is small and do not raise animals, but it could be transported from elsewhere for the purpose of composting (not sure). I am asking previous intern, hope they know what it is.
    – y chung
    Oct 20, 2016 at 15:49
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    Hi! If the previous intern or someone else is able to figure this out for you, the community would love to know. SE encourages people to answer their own questions, so feel free to write an answer when you have one. That way anyone who comes across this later will have all the information. Good luck! Oct 20, 2016 at 20:03
  • @ Sue and everyone helping me, the previous intern and my boss have a not 100% certain answer up to this moment. It is likely to be pelleted chicken manure tranported from a nearby farm. My boss also mentioned it can be mouse bedding from labs, since another colleagues are working on related things. I need to wait for more answers from more colleagues and people involved before arriving at a conclusion. Everyone is enjoying holiday due to tropical cyclone in my home place, so I will need to wait some days before getting their reply. Thanks again for everyone's help.
    – y chung
    Oct 21, 2016 at 4:48

2 Answers 2


I think we are looking at wood pellets, the kind used for pellet stoves. I use these same pellets for horse bedding, they are wonderful. They are also used to compost solid sewage for those self contained composting toilets. Yes, could be bedding for small animals, too, or cat boxes.

For my horses, I would poke a hole in a bag and fill it with water from a hose. Allow it to absorb the water for an hour or less and then dump to spread on the floor of a stall. Lovely stuff.

It is nothing more than sawdust pressed together in little hard pellets. Great for brown ingredients in your compost.

If the previous owner was using this for hamsters great. For cat box litter not so great at all. Cats eat meat. Poop from omnivores and carnivores should never be mixed into compost. High incidence of heavy metals and other stuff.


That's what feed grain pellets look like once they start decomposing (after humidity affects it). I'm guessing that's what that is, probably grain that went too far to feed.

High protein content and some fat mean this is a valuable addition to a compost heap, but mix it thoroughly rather than have it in a pile, so that you get more bacterial action and less mold action (the bacteria is what fixes the nitrogen into the organic atter).

This is the shape the feed is in fresh from the mill (before decomposition starts):

enter image description here

  • 1
    Cool, J.! Same color only made of 'grain'?
    – stormy
    Oct 21, 2016 at 22:06

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