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Friday, June 11, 2010

That Compost Tumbler

I thought I should explain about the compost tumbler I mentioned in the previous post.  There are large ones with a crank handle to rotate a large drum on a frame and there are smaller ones you just roll around on the ground to keep the materials mixed.

I have the large one on the stand.  It seems like a great idea.  The kitchen waste is safe from scavengers and the handle makes it easy to thoroughly mix the contents.  The frame holds the drum just above the height of a wheelbarrow, so it ought to be easy to unload the contents when "cooked".  There are vents for letting air circulate for aerobic microbial breakdown.

I don't know about the small portable ones, but the big ones don't work!

1.  The vents are too small for good air ventilation, so the breakdown occurs mostly anaerobically ("without oxygen").  Anaerobic decay is cold and slow, which means weed seeds aren't killed and it takes forever.  It also smells bad (anaerobic microbes produce ammonia).

2.  It is awkward and messy trying to get the material out when you want it.  The drum is too high to shovel the stuff out, and turning the opening to the bottom to let it fall into the wheelbarrow doesn't work well.  It doesn't want to fall out on its own, and rotating the drum back and forth over the wheelbarrow spills half of the "compost" on the ground.

3.  You would think a metal drum in the sun would heat up on its own.  Nope!  The vents are large enough to prevent that.  The door does get hot enough in Summer though to approach "painful to remove".

4.  The thing is a haven for insects.  Clouds of fruit flies come out each time I open it.  And there is some sort of black fly that loves the rotting (yes rotting, not composting) material as breeding grounds.  I've had to take the vents apart several times to empty out all the dead bodies because that's where they try to escape through.

Do yourself a favor if you are considering one of these things.  Build a normal compost bin instead!

1 comment:

Jacqueline said...

Too bad you had to find out the hard way; nice of you to post and let others know.