What’s Going On in Your Compost Pile?

By on April 08, 2011

Compost is an essential addition to an organic garden

It’s a war in there.

Or the cycle of life. And death. And decomposition.

There’s a fascinating ecosystem that turns your mound of oak leaves and banana peels into soft, sweet-smelling humus to nourish your plants.

Ready to start a compost pile? Watch our new video, Composting 101, for Tricia’s basic instructions.

Whether you have a compost pile on the ground or an enclosed compost bin, the dramatic process is the same.

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What happens in composting

The pail full of kitchen scraps you take out to the compost pile is full of nitrogen. When you toss the scraps on the pile you’re giving nutrients to the bacteria there.

As the bacteria consume the plant sugars in your kitchen scraps they heat up the pile. Turning the pile weekly with a compost fork or a compost aerator adds oxygen to the pile and encourages the bacteria. If your pile is really active, the bacteria population can double every hour!

When your compost bin is really “cooking” check the temperature every day with a compost thermometer and see when it peaks and then declines.

To keep your compost pile healthy be sure the critters have nitrogen and carbon, water and oxygen. A lack of any of those will slow down or stop decomposition.

So who is causing all this heat? Who keeps breaking the pile into tiny pieces?

The cast of characters in your compost:

Act One

microorganisms rule and it’s a hot time
Aerobic bacteria (three kinds, the hotter temps boost the hardest workers)
Actinomycetes (they form that cobwebby stuff in a compost pile)

Intermission temperature declines

Act Two

macroorganisms increase
Fermentation mites
Sowbugs & pillbugs
Enchytraeids (potworms)
Flies! (bury your kitchen scraps deep in the pile to keep those fellows away)
Snails & slugs
Grubs (larvae of fruit beetles)
Earwigs (it’s an all-you-can-eat buffet for them: insects at all stages, algae & fungi)
Ants (they signal that your pile is too dry)

Act Three

temperature declines and the human returns
Human removes compost or “humus” from the pile. Spreads it as top-dressing on beds, amends soil before planting, or adds it to potting mixes.

Lots of these “characters” are still in the humus and they’ll enrich the garden soil’s ecosystem .

The humus will improve soil quality and structure—increasing drainage in clay soil and moisture retention in sandy soil.

Read the reviews

Is your interest in composting piqued? There are lots of great books on the subject. One of our favorites is The Rodale Book of Composting.

  Comments (10)


I’ve been trying to organically grow my vegetables for the last few years. Last year we didn’t do to good. I started a compost three years ago, it smells good but I’m not sure its quite ready.Can I use some of it to make the tea?
            Thanks, Patricia

Posted by patricia miller on Jun. 05, 2011 at 3:51:01 PM

Patricia, If your compost is dark and mostly crumbly and smells good, it’s “finished”. Put it through a piece of screen to sieve it, and yes, go ahead and use it to make tea, top-dress your soil, or dig it in to your soil.

Posted by GrowOrganic.com on Aug. 18, 2011 at 12:05:55 PM


My compost is in a bin and has quite a few pine needles.  They do not rot easily and my finished product always has whole ones in it.  Is that ok for my vegetable garden soil?

Posted by JR Stoner on Mar. 29, 2012 at 3:06:29 PM

JR, Pine needles decompose slowly because they have a waxy coating. In the future, see if you can run a lawn mower over them before adding them to your compost pile. They are acid, but that acidity eventually vanishes during the composting process. Otherwise finished compost that contains whole pine needles would be okay to spread on the top of your vegetable garden but not to dig in. I hope this is helpful. Please let me know if you need more information.

Posted by GrowOrganic.com on Mar. 30, 2012 at 4:16:21 PM


Since I live in a pine area, adding pine to the garden in my compost would seem that I should add a little lime for a more successful soil.  I have not tested ph, but probably should.  To add to this scenario, we lost a huge pine tree to a lightening strike, and I added the shavings from cutting it up to my garden area.

Posted by JR Stoner on Apr. 14, 2012 at 9:18:51 AM

JR, Here’s some info from Cornell University about using tree bark as mulch http://www.gardening.cornell.edu/factsheets/mulch/mulchland.html

In finished compost there will not be an acid residue from the pine needles, but that is only if the needles have completely broken down.

I agree that you should do some pH testing. This is the perfect time of year to do soil tests of all kinds, so that you can amend soil if necessary before the vegetable planting. We offer many kinds of soil tests, both DIY kits and sophisticated analyses http://www.groworganic.com/fertilizers/soil-test.html

Posted by GrowOrganic.com on Apr. 14, 2012 at 8:26:13 PM


I watched Tricia’s video. In it, she said not to use dairy scraps. Cheese comes to mind, but what about raw goat milk. I was told that it was good to add older milk that we don’t want to drink any more to the garden or compost, instead of dumping it down the drain. Is this OK, since the enzymes etc haven’t been killed from pasteurization?

Posted by Lori on Nov. 12, 2012 at 6:32:07 AM

Lori, Dairy should not be added to a standard compost pile, whether it is raw dairy or not. The proteins and fats in dairy (and meat) do not break down quickly. The typical problem with adding dairy is that the compost pile will smell and attract pests like r-a-t-s.

Posted by GrowOrganic.com on Nov. 12, 2012 at 8:04:57 PM


Hi Charlotte, I am a junior in high school and want to start a garden at home. I live in the city and its not easy for me to get animal manure among other things what is the best way to start my own compost fast and effectively. Thanks!

Posted by Perla on Jul. 28, 2014 at 4:11:32 PM

You can compost kitchen scraps, grass clippings, dead leaves but not waste from domestic animals. Watch our video on composting to get more information on starting a compost pile.

Posted by Suzanne at Peaceful Valley on Jul. 31, 2014 at 5:06:10 PM

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