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Should I Insulate My Tumbler Bin?


December 24, 2016

My tumbler has gone cold.....I should have thought ahead about this inevitability, but I did not! So I am wondering what ideas you might have for what might be best to use.....water heater insulation blanket? Mylar sheets? I want it to be able to take advantage of the sun (I am in Placitas at about 6500') but am not home all day to take insulation off when there is sun, and put it back on when the air cools..... Thank you,


Answer by JZ: Yes, we are in the grip of winter.  Other colleagues may respond to your question.

"Cold" composting operations in a tumbler will have temperature swings with the ambient air temps. Cold composting operations do not necessarily generate heat internally and are usually not of sufficient volume (see below) to insulate the heat that may develop. Adding greens to browns would be useful, e.g. manures, fruit/vegetable scrap, coffee grounds, alfalfa pellets - these provide protein for microbial proliferation.

You could consider your tumbler method  as part of a 12 month cycle - decomposition will slow now, but will pick up as the season changes.  Keep up, decomposition is happening.  Be sure to maintain 50% moisture in the bin. If your tumbler is in a sunny location during the day - and adding some greens, that is the best you can do for now. Leave it uncovered at night if that is not convenient. Sure, covering at night would be useful - the blanket you mentioned would be helpful. Surrounding the tumbler with straw bales and/or cardboard may be helpful too.

If you would like to do "hot" composting in a tumbler, then you would need one that holds about 170 gallons - 3/4 full with 50/50 greens/browns with coarse bulking material.  This volume would keep in/insulate the heat that develops internally. This weight/volume of wet organics becomes difficult to tumble due to the weight.

Hope that this is helpful.  Let us know if you have more questions.

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