Thursday, July 22, 2010

What to Put in Your Compost Bin

Now that we have compost bins we have to fill them.

The size of your compost pile and a proper mix of materials is the key to good composting action.

A 4 x 4 x 4 cube is the ideal composting size.  In our case, we took the 4 foot square cube and sloped the front of the cube for easy access.

Filling them has been relatively easy because we had a pile of materials just waiting to go in.

Materials included:

horse manure
wetted down sawdust
sod with some dirt attached
cut lawn grass
kitchen scraps (including egg shells, vegetable and fruit stems, seeds and peelings, and coffee grounds)

This is actually an ideal scenario because you can layer each material in the bin, giving it a bit of water to moisten as you go along.

Here's the first bin completely full with layers
Within a week this bin was hot.  It's hard to tell when the weather is hot anyway but if you stick your hand over top you can feel it.  For those who aren't squeamish you can stick your hand right in there.  A compost thermometer is often recommended but honestly, if you can feel the heat with your hand do you really need a thermometer to tell you the temperature?

Two weeks later and the material is starting to compress.  It's hard to make out but the level has begun to sink in the picture below.

This means the materials are starting to break down but it also means you'd better get in there and stir!  The materials are starting to compact under their own weight which means there's no air getting in which will slow down the composting process.  Although materials will continue to compost without air circulation the composting will slow down considerably and things will start getting smelly.  Nobody likes a smelly compost bin!

If you find your bin is attracting masses of flies and the smell is overpowering it is likely out of balance.  This means you may have too many green or brown materials, too much water or not enough air.  Think of baking a cake, if your batter is too wet you throw in some flour to bulk it up.  You want something that's not too dry but not sloppy either.  Same with compost.  If it's wet and slimey try throwing in sawdust, straw, dried leaves, or shredded paper.  This should suck up the excess moisture and balance things out.  Conversely a dry pile will also start to smell sour.  It needs water and some green material. 

Stirring your compost means you're adding air.  The organisms breaking down your materials for you need air to breath, don't let them down!  Another benefit to stirring is that it brings materials from the outside of the pile to the inside allowing them at the heat in the middle to better break down.

Now I made a mistake that I should warn you about.  I was in such a hurry to get some green material into my bin that I dumped whole weeds in there.  Some people recommend that you shouldn't compost weeds, or at least stay away from them when they are in seed because your compost will then be full of weed seeds.  I agree when it comes to particularly aggressive weeds like bindweed but dandelions don't bother me (the seeds will just blow in from my field anyway).  What I did find a problem was that I didn't cut the weeds up.  When I tried to get my garden fork in the bin to start turning it kept getting caught up in all those darn weeds.  So I had to try and cut some of them apart after the fact which was messy and not entirely pleasant.  If you're able, cut up large materials before they go in the bin.  The smaller the better.

With any luck we'll have some finished product to show you in about 6 weeks time.  I'm hoping there will be enough to top dress my newly planted trees and new flower bed in the fall to prepare them for winter.


  1. Ah, now I know where my wife got her cake recipe :)

    That was the first White Spotted Sable moth I remember seeing. I may have but never 'noted' it, that's why I did the post - my memory needs to be kick started these days.

  2. Now we know why you're called WiseAcre :)