The bottom line is that anything that was once alive can be composted. Some things, however, are best avoided, because they attract vermin and create problems within the compost cycle. These would include meat and dairy products.
What mixture to use.
While some experience is necessary, what you’ll find in practical terms, is that an equal amount of green to brown by weight works best.
Green ingredients are quick to compost and are high in nitrogen
- Urine, diluted with water 20:1.
- Comfrey leaves, nettles and grass clippings.
- Raw vegetable peelings.
- Tea bags, leaves, coffee grounds.
- Young green leaves or weeds, avoid plants with seeds.
- Soft green pruning.
- Animal manure.
- Grass clippings from lawn
- Poultry manure.
These are carbon rich or slow to compost materials.
- Cardboard such as cereal boxes and egg cartons
- Waste paper or junk mail, I personally enjoy shredding income tax forms.
- Cardboard cubes.
- Glossy magazines. While these compost is often better to recycle them than compost.
- Newspaper. This is the same as for glossy magazines.
- Any bedding from veggie-eating pets such as rabbits or guinea pigs.
- Tough woody clippings. Note these will compost faster if chipped up with a shredder
- Old bedding plants.
- Sawdust or wood shavings.
- Leaves in the fall.
- Other things you can compost.
- Very small amounts of wood ash. Very small.
- Crushed eggshells.
- Natural fibers such as 100% wool or cotton
Do not compost.
As a rule of thumb, do not compost meat, dairy, fish, cat litter, dog feces, or disposable diapers.
Here are some other questions answered about what can go into the compost pile (or not)