Recycled Barrel Composting For Low Humidity Climates

A failure as a composter, a success as a rabbit-guard:
Failed compost bin

After ten years of composting garden clippings I have definite opinions about composting.  That standard advice of "keep the compost as moist as a wrung-out sponge"?   I have found it useless.  Here in Southern California, a wrung-out sponge stays moist for about forty-two seconds.   Unless you want to spend your life constantly re-moistening your compost pile, you may need to approach the problem differently.

I've decided that composting is as climate-sensitive as plants are, and success requires adjustments. 

I suspect the standard composting advice works perfectly in the summer humid heat of the Midwest, southeast, and eastern United States, and in the moister Pacific Northwest.  Here:  no.  Here compost doesn't readily compost--it mummifies.  It's nearly impossible to keep any moisture in the pile, if you rely on a small pile, or if you rely as I did on hoops of left-over wire fencing covered with a plastic sheet.  

My mummification problem ran head on into another decided opinion I have about composting:  never, never spend a penny on it.  Selling expensive "compost starter mix" I view as a criminal activity.  Ditto with $300 compost bins.   It is insane to spend money on composting, when you can spend it on plants that you may later have the pleasure of composting. 

Ten years ago, my first composting method was the pile-up-and-leave-it method, which worked well when the back of our property was unfinished and in deep shade.  Winters were receiving normal  rainfall, so there was more available moisture.  I had a single medium-sized (5'x5') compost pile.  Where compost piles are concerned, size absolutely matters.  Bigger is always better.   Since I had a large area, I would fork the pile back and forth  from one spot to another to mix and aerate.  It worked.  (In addition, the soil underneath this area became the finest soil in the garden, rich with humus.)

The good stuff:

My composting method had to change when we finished the back area.  Once it was completed, there was no longer deep shade, nor was there a large space for a big pile.   I had some leftover wire fencing so I made hoops and started composting in a smaller area, moving material as it composted from one hoop to another.  I kept sheets of plastic over the top of the piles to hold in what moisture there was.  That worked--okay.  It composted in the very center of the hoop; the outer areas remained as they were.  More moisture and more plastic covering helped the composting process.

Then we got our three-year stretch of drought.   Instead  of winter rain, we got howling desiccating Santa Ana winds.  The compost stopped composting.   I wasn't about to use precious water on it constantly  (remember:  never spend a penny on composting!) and it wouldn't have helped anyway.  The compost piled up and sat.  I started running out of room,  because it just didn't compost.  Extreme dryness shrunk it somewhat, but not enough.  To increase moisture, I started adding lots of used coffee grounds from Starbucks and Peets.  Unfortunately, the grounds dried out and mummified just as well as my garden clippings.

Then came  a big turning point.  The waste-pickup company outlawed our own green-waste barrels and provided a company version:

Uh Oh!

Uh Oh!  Formerly we provided our own standard 33 gallon trash barrels for green waste pick up, and the allowed number was unlimited.  I admit I don't compost everything.  Tree branches and rose canes go into the green waste.  I don't have the space to let them sit for 5 years while they break down.  So our 33 gallon barrels got used, and lots and lots of them got used during rose pruning season.  Then I made friends with the trash guys and  found out plastic bags were okay with them (easier and faster for them to lift), so I could toss a dozen bags of canes at a time.  Then that bin pictured above arrived.   The unlimited green-waste party was over.  Now we have just one bin for green waste.  Yikes.  

Thus our composting technique had to improve.  And as it happened, we had plenty of now-idled 33 gallon trash barrels.  So the never wholly successful wire cylinders are were retired as compost bins.

I cut the bottoms out of my barrels, flipping them over, and using those to compost.  This morning I went out to dump some tomato glop, and lifting the lid of my new barrel composter, to reveal a hot, moist environment.  It felt like Houston in August in there, exactly how a compost pile should feel.  I wish I had done this nine years ago.  Perhaps in Houston this method might create compost that stinks to high heaven, given their heat and humidity, but here it will work.   To heck with  those wrung-out sponges! 

Better compost bin
It's that simple.  Cut the bottom out of a barrel.  Turn it bottom end up, and find an out-of-the-way spot to place it on bare soil, a space at least two barrels wide.  Not on pavers, and not on concrete:  on soil.

Why on soil?  Because all the microbes you need are in the soil waiting to migrate upwards into the barrel, attack the clippings and turn them into compost.  No matter how bad the soil is, the microbes are there, hungry and waiting.  Use the barrel lid as the lid for your composter. 

Just keep adding stuff, like garden clippings and vegetable peelings from cooking, and your coffee grounds and tea leaves.  Because of the partially closed in nature of a barrel, the clippings compost quite fast.  A slight tip of the barrel will let you see if there is any ready-to-harvest material at the bottom of the barrel.

Finished compost from bottom of barrel:

When it's time to harvest some compost, you can do one of two things.  You can tip the barrel slightly and trowel out the most finished material right at the bottom.  Or you can pull the barrel up, move it over to a slightly different spot, shovel all the unfinished stuff back into the barrel, and collect the finished compost.  I like to screen or sift my compost a bit.  Rather than buying a screener, I've discovered that the black plastic flats that ground cover plants or six-pack plants come in makes a great screen.  Doubling them up gives extra strength, but a single works well.  And you are keeping yet another chunk of plastic out of the trash stream for a while.  When the flat becomes brittle, recycle it and find a new one. 

Recycle a groundcover flat as a compost screener:

Adjustments:  if you consistently find the material is just too wet, you can add more dry material (fallen leaves), or use a hole saw to drill some holes in the sides of the barrel.  This will create a slightly drier environment.   If your material is too dry, add your leftover coffee, tea, or cooking water from the kitchen, or more used coffee grounds from a Starbucks or Peets.  Why use valuable clean water on compost?


An update here.

Update 2/3/2013.  I continue to refine this composting method.  I eventually moved my compost barrels again, this time to a more accessible but still hidden location in the garden.  I dug holes for the barrels so I could set them halfway below grade.  This made them less visible and more stable.  The barrels also right-side up again.  It's easy to pull them out of the hole when it's time to compost harvest. I plan to add more barrels soon.  
 photo composter3277_zps2b5b73c4.jpg


  1. I see in your picture that you have plastic and the lid over the tub. How will this affect the moisture level? Is it to keep it in or to keep it out? How do you get enough air inside? Thanks.

    1. Hi Renee, it is to keep moisture in, and it works. The lid didn't fit tightly so I added the piece of plastic.

      Update: I moved the compost barrels to a more easily accessible but still hidden spot, and dug holes for them so half the barrel is below soil grade and half is above. Now they are a little less visible, and I can pull the barrel out of the hole for compost harvesting. The lids are getting old and the plastic is cracked enough to let in a little air but keep in almost all the moisture. I'm getting excellent compost and plan to add more barrels to the area so I can compost more material. I guess I should do an update with pictures...


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