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Black gold-why is my compost lackluster?  RSS feed

Liz Hammond
Posts: 16
Location: Western Washington Zone 8a
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Hi Permies!
I've been hoping my humanure compost would produce that great dark brown/black worm-casting quality. What I have is much lighter brown, and still sawdusty. This is about a year and a half since we stopped adding to it. The volume decreased by about two thirds in that time.
Inputs included Douglas-fir sawdust from our bucket system, some straw to cover bucket material, and all kitchen scraps for 2-3 person household. I also added fall leaves, and for awhile any red wigglers I came across in my yard puttering probably a dozen or so over a couple weeks.
I thought that the ammonia levels would be high enough to meet the nitrogen demand, but the sawdust just seems to dominate.

I've attached a photo of the "done" compost and a side by side of the "resting" and "done". Both piles are in direct sunlight, and used to be covered with a scrap glass window to create a "greenhouse effect".
What can I do differently to get that lovely "black
gold"? Does it need more diverse nitrogen sources? Any advice appreciated!

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Harry Soloman
Posts: 92
Location: Pennsylvania, Dauphin County
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The standards is what I say to check; temperature, moisture and such. 

I would consider some natural farming inputs such as  indigenous microorganisms 5 and adding to the compost and it will break down that nitrogen very well.




Hope that helps or points in a good direction for you.
Roberto pokachinni
Posts: 1335
Location: Fraser Headwaters, B.C., Zone3, Latitude 53N, Altitude 2750', Boreal/Temperate Rainforest-transition
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I think your intuition is probably right.  If you are still seeing sawdust like structure, then you are likely still needing more nitrogen to break down the last bit of woody stuff, although inoculating with fungi might be the best way to accomplish the breakdown at this stage. 

The good thing is that some of your woody sawdust material has done the job of absorbing and breaking down your humanure (and the humanure has done it's job of breaking down some of your sawdust), as the reduction in the pile size and the indication of lots of stuff that is broken down are likely indicating.

If you are scooping sawdust type material into your humanure toilet/bucket/whatever, and you are not coming into direct contact with it except for your scoop, you could put this stuff in your system again, and it would already have a millions of microbes in it that are specific for breaking down humanure, and your humanure specifically.  (at any rate you could put a bit of it in the bottom of your humanure buckets so that each bucket has this great ingredient to inoculate your system with microbes).  If you are not comfortable with scooping the not fully composted stuff, you could use this material in pee buckets, and that would give the uncomposted sawdust a great nitrogen fix... but that might take a while, and you may not have so many buckets. 

Douglas fir and many other conifers are resin rich and are not ideal in my thinking for this purpose.  You are better off getting sawdust that is made form alders, cottonwoods, aspens, birches, or other deciduous trees as these break down much more effectively with moisture.  One things that you can do if you only have access to conifer sawdust is to age it in small heaps that you dampen so that it gets inoculated with local fungi first.  You will know that this has happened as the sawdust will brown up, and if you dig in it, there will be visible white thread like hairs in the sawdust.  After you know that it has fungi in it, it will be much more effective at taking on other living organisms, and absorbing your humanure as you add it to your toilet bucket.  

It might also be that your greenhouse solarizing bins are too dry.  There are a lot of microbes that simply go dormant or die if they don't have enough moisture.  By adding a bit of moisture, when you build your piles, and periodically again as you age them might make a difference. 

It could also be that your bucket load and your piles are not as aerobic as they should be, and just need to be turned a few times to generate the aerobic activity that certain microbes need so their populations explode and consume the carbon.     
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