Composting

Setting up a backyard composter

Choosing a site:  for the best results your compost bin should be positioned in an easily accessible sunny or partly-sunny spot, on well drained soil. The soil below the bin should be loosened to improve drainage and increase access for worms and bacteria.  It helps to have room for a pile of dry leaves next to it.  Place a few inches of kitchen waste on the soil at the bottom of the bin, this will attract worms and bacteria to the bin and increase the rate of compost formation.

Size consideration:  Your compost structure or compost pile must be at least 7 cubic feet to provide enough heat, air, and moisture for adequate decomposition.  How do you calculate the volume of your composter?  If it is 2 feet wide, 2 feet long and 3 feet high, the volume is 2x2x3=12 cubic feet.

Making or purchasing a composter:  Making your own composter  is as easy as staking out 6' of chicken wire to form a vertical tube, or, being very creative with scrap wood.  There are many websites on the web and books in our libraries dedicated to building composters.  Alternately, you can buy a moulded plastic composter or fancy cedar one, depending on your budget. They are available in Reno-Depot, Rona, and most big garden supply stores.  

Here are the most common types of composters:

	ADVANTAGES	DISADVANTAGES
HOME-MADE ENCLOSURES from chicken wire, snow fence,  wood, screens, bricks, etc.  Lids can be made from framed screens, etc.	Generally little or no cost with use of scrap material Enclosures from light material are easy to empty or relocate Custom-made means it may be easy to adapt to evolving needs Easy access to underlying soil for migration of beneficial worms and micro-organisms	Some materials (bricks, etc.) may be expensive Structures from heavy materials may be hard to relocate Easy pest access unless lid also provided Manual aeration required
MULTI-COMPARTMENT COMPOSTER BINS.  As one bin is filled up, the next bin can be started, allowing the previous one to age and finish decomposing.  By the time the last one is filled, often the first one is ready to be used in your garden.	Users can let older compost "age" without mixing it with new material Good for managing large quantities of compost  Easy access to underlying soil for migration of beneficial worms and micro-organisms	Materials to build may be expensive  May be labour- intensive to build Difficult to move Manual aeration required
MOLDED PLASTIC COMPOSTERS with no bottom	Fast set up Available in most hardware stores or nurseries Many different models and sizes are available Easy access to underlying soil for migration of beneficial worms and micro-organisms	More difficult to turn for aeration. Users may address this with a specialized aerating tool
CYLINDRICAL TUMBLERS can be purchased or built.	No access by pests Easy to mix the compost materials Various models are available A cheap alternative can be constructed by drilling drainage holes in a  cylindrical garbage bin with a  lockable lid.  It's tumbled by "kicking it around the garden".	More expensive to purchase than a regular bin No contact with the ground to allow for migration of beneficial worms and micro-organisms
COMPOST PILES	Simplest Easy to relocate Easy to access for aerating and adding new materials Easy access to underlying soil for migration of beneficial worms and micro-organisms	Easy access for pests who may dig out leftovers and make a mess New kitchen scraps need to be completely  covered in leaves, etc each time  to minimize this problem May be considered unsightly by neighbours

Filling a composter

What to put in a composter? Everything that has been grown naturally, with minimal or no pesticide use, can be tossed into your composter as long as you get a balanced mixture of wet/green materials (1/4 - 1/2) to dry/brown materials (1/2 - 3/4).   Wet/green materials (such as  vegetable scraps or freshly-cut grass)  are high in nitrogen, decompose easily, and tend to rot if on their own. Dry/brown materials (such as dry leaves, straw or wood chips) are high in carbon and decompose slowly if on their own.  Layering is the best approach for quicker breakdown of organic waste to humus-rich black soil.

Here are some common materials from your yard, kitchen,  or around the house that can be composted:

GREEN MATERIALS	BROWN MATERIALS	NOT FOR COMPOST
grass clippings (best mulched) fruit and vegetable scraps wilted flowers, dead plants weeds that haven't gone to seed	dry leaves coffee grounds and filters tea bags egg shells (crushed) rice, pasta and bread feathers soil rock dust straw, hay, sawdust shredded paper	meat or bones fish products shells from oysters or other shellfish milk products oil pet waste weeds that have gone to seed diseased plants or leaves spruce or pine needles rhubarb leaves walnut leaves

Optimizing the composting process

Left on their own, the green/wet and brown/dry materials decompose very slowly.  Adding them onto the compost pile in successive thin layers is already a good start at speeding up the decomposition process.   You can optimize the process further as follows:

1. Feed the compost with smaller particles

Large pieces of plant trimmings or vegetable scraps (broccoli stems, cabbage hearts, etc)  take longer to decompose than smaller ones.  They can also become entangled and make stirring problematic. Whenever  possible , chop up large pieces into smaller ones to speed up decomposition.

Dry leaves decompose faster if they are mulched.   Oak leaves with their tough surface decompose particularly slowly, so those should be mulched to be composted.  To mulch leaves, drive over them with your mulching lawnmower a few times before raking them up in the fall.  

2. Aerate/Stir the compost periodically

The primary purpose of aerating and turning the compost pile is to increase oxygen flow for the micro-organisms, and to blend un-decomposed materials into the centre of the pile.  Either a pitchfork or a specialized aerating tool will do the trick.  By stirring the compost, you'll also ensure more even distribution of moisture.  Aerate every 2-3 weeks, turn the whole compost pile once or twice a year. 

3. Watch the moisture level

If the compost is too wet, it tends to rot and produce unpleasant smells.  If it is too dry, the micro-organisms responsible for decomposition will die out and the composting can slow down.  Add water or dry brown materials to restore proper moisture level which is comparable to a wrung-out sponge. 

4. Temper your expectations in the winter

The work of the micro-organisms in the compost generates heat in the middle of the compost pile.  Although larger piles tend to produce more heat and therefore remain active longer into the winter,  the compost will eventually freeze solid in our Quebec winters.  The piles therefore stop "shrinking" until the next thaw when the micro-organisms become active again.  If you run out of space in your regular compost container, a second container or pile may tide you through the winter.

To make sure that you have enough dry material to last you the winter and the following summer keep  at least 2 - 3 bags of dry leaves (more if you produce a lot of organic waste) in the fall for winter and summer composting.

5. End with the brown

As you add fresh kitchen scraps onto your compost, always cover them with a layer of brown (dry leaves, shredded paper, straw, etc.) .  Pests such as squirrels, crows or raccoons will be less likely to come rummage around the pile, and the scraps will decompose faster on the inside of the pile.  

6. Avoid these non-compostables

• Never use rhubarb leaves or cedar chips in your composter; their essential oils are too strong and can kill off the friendly microbes. 

• Peony foliage should not be added to the compost pile because botrytis blight (also called gray mold), a fungal disease that affects peonies, sometimes survives the composting process.

7. And for an extra boost..

• Keep some of your finished compost (humus) back to add to the bin when you restart it.  It's full of composting microbes.

• Manure (chicken, sheep, horse, most herbivores) is a great addition to your compost, full of hard-working micro-organisms which speed up the composting process.

• The herb Comfrey (Symphytum officinale) occasionally mixed into your compost bins acts as an accelerator.  Commercial accelerators are not necessary.

Trouble-shooting common problems (smells, pests, etc.)

1. My compost smells like rotten eggs.

When the content of your bin (the mix) is too wet, decomposition slows down and odour increases.  This is because the mixture is lacking in oxygen.  Without oxygen, the bacteria and microbes that decompose your scraps cannot do their work effectively.  Mix in a lot of dry leaves (shredded newspapers, straw, ...) to bring the compost material back to a balance between wet and dry material.  By mixing these compost materials, air will be added, and the bad odour should go away after two or three days, the decomposition of materials will increase, and your neighbours will be happy.

2. My compost smells like ammonia.

You have added too much nitrogen rich material (i.e. green material) -- add dry brown material and mix.

3. I've got fruit flies.

Keep fresh food scraps well covered with leaves or soil

4. My compost is going grey on top.

Add water until it has a damp sponge-like consistency.

5. Pests are invading my compost.

Sweet-smelling melon rinds and many other exposed kitchen scraps attract raccoons and squirrels.  Always cover your newly emptied kitchen scraps with a lawyer of brown materials (dry leaves, straw, etc.) to prevent odour.  Have a tight-fitting lid on your compost bin or avoid using particularly attractive ingredients for a while or dry them out before using them.

Vermicomposting

Vermicomposting is the process of using red earthworms to turn our kitchen food waste into highly nutritious humus for use on house plants, lawns, shrubs and gardens.  Worms, as one of nature's crucial and efficient recyclers, can produce nutrient-laden food which can then be returned to nature and ensure a healthier planet.

Worm composting, which can be done all year round, is ideally suited for both home and apartment as the worm bin takes up very little space.  It can be located outdoors in summer and indoors in winter and, with proper maintenance, is odour-free.  Approximately every 3-4 months, worms and their castings (humus) need to be separated and the worms placed in new bedding so the cycle can repeat itself. 

More information on composting

For information online, check out our compost-related links.

There many composting how-to books available at public libraries. Some titles in the Beaconsfield library include:

• Let it rot! The gardener's guide to composting by S. Campell
• The Rodale Book of Composting
• Worms eat my Garbage by Mary Appelhof
• Les Vers: Des croyances populaires au lombricompostage by Maurice Dumas

Also available from the Beaconsfield Library is a 10 minute video, produced by the manufacturers of The Earth Machine composting bins, on the basics of composting