The basic rule of thumb is simple: almost anything made from organic material, except a few organics that need to be excluded. Compost works best when you combine “green” materials with “brown” ones, at a ratio of 1 part green to 4 parts brown.
The standard garden and home wastes that can be composted
Green:
- Grass clippings
- Vegetable food scraps
- Disease-free yard and garden waste
- Vegetarian animal manure*
- Crushed egg shells
- Fresh tree and shrub leaves
*It’s important to have compost achieve temperatures between 32-60 °C (90-140 °F) to kill any pathogens in manures. See inset on keeping compost hot.
Brown:
- Dry tree and shrub leaves, evergreen needles
- Coffee grounds and paper filters
- Shredded newspaper and printer paper (not glossy)**
- Shredded flat cardboard and corrugated cardboard***
- Wood shavings (excluding pressure-treated wood)
- Wood ash (excluding pressure-treated wood)
- Small woody materials
** Inks used on newspapers are safe and non-toxic. Includes black and white as well as coloured inks.
***Cardboard without wax coatings. Must be shredded or cut into thin strips to be useful.
Considerations of materials that could also be used:
- Cooked food scraps containing small amounts of meat. Also, bread and pastas. That is, if you have a closed bin that animals cannot get into.
- Leftover fertilizers: If you have some old product that you have no use for or that has gone hard/lumpy, break the lumps up and spread a thin layer on your compost. The nutrients are both useful in helping decomposition, and also in improving the finished compost for when you work it back into the garden soil.
What you should not put in the compost
- Meat, fat, oils, bones: these carry a risk of disease and/or are a true attractant to pesky rodents and raccoons.
- Cat litter and dog feces: there is a potential of these inputs carrying diseases that can’t be eradicated in the composting process.
- Diseased garden waste: if you had blight on a vegetable, the compost process cannot kill the disease.
- Charcoal ash from the BBQ: contains chemicals.
The benefits of composting at home
There are so many benefits to home composting. You’re not only diverting useful materials from landfills, you’re also controlling the inputs going back into your garden.
Finished compost improves garden soil by:
- Supplying organic nutrients to plants.
- Increasing airflow and water retention.
- Enhancing soil structure.
- Supporting beneficial bacteria and soil health.
- Encouraging earthworm populations, which in turn, aerate the soil.
- Reducing soilborne diseases.
Depending on the materials used and the size of the compost pile, decomposition can take anywhere from months to a year or more (if just leaving the pile static and not turning it over). You can shorten the composting time by using a compost accelerator, which has organic nutrients and enzymes that encourage decomposition.
The best success is achieved by having two compost bins. One that you fill up all season, but stop adding anything new in the fall, or when it is full. Then you start a new bin while leaving the first filled bin alone until later next season. It is hard for the material in the bin to finish composting if you are continually adding to it. That’s why you make a hard stop at this point and begin filling a new bin.
Now take your finished compost and spread it in and on your garden!
How to keep compost hot
Hot composting is odourless, attracts fewer pests and keeps the decomposition process active. Here’s how to increase the temperature of your compost pile.
- Try to keep a 4 brown to 1 green ratio. Often, lack of green is the culprit in not heating up.
- Throw in good garden soil from time to time. It is full of bacteria, which could be lacking in your compost.
- Add water if needed. Reach in and grab a handful. Compost should feel like a damp sponge.
- Turn over the pile with a pitchfork a few times a season to make sure their air gets into the centre.
Don't forget to download and print our composting guide.
