The terms are generally descriptive. Browns are brown plant material, and greens are green plant material. Some examples include the following:
Greens:
- Kitchen scraps (watermelon rinds, carrot ends and peels, banana peels, rotten avocados, cucumbers, lettuce ends, apple peels and core, artichoke petals and stems, mango skins, avocado skins, strawberry tops and leaves, celery ends)
- Coffee grounds
- Tea leaves
- Rice, raw and cooked (can attract pests)
- Bread, stale or moldy (can attract pests)
- Grass clippings
- Fresh pine needles
- Fresh plant cuttings
- Fresh leaves
- Horse, chicken, rabbit, cow manure (without medications)
Browns:
- Brush
- Twigs
- Hay
- Straw
- Pine needles
- Dried grass clippings
- Dried pine needles
- Dried plant cuttings
- Dried leaves
- Cardboard
- Non-glossy shredded paper
- Paper tea bags
- Paper grocery bags
- Paper towels
Note that while any of the above items are compostable, if you add pesticide-contaminated items to the compost, it may not only kill needed microorganisms, it will end up in the food you grow using that compost.