Green & Brown Compost

Green Materials

This page contains ratios for green to brown compost. The ratios will be in the format of the following example: (green number:brown number).

• Coffee grounds (20:1): Coffee grounds are high in nitrogen and help heat up compost. Any kind of coffee grounds are able to be composted, and if you are using a paper filter, that can also be composted (if you are in need of additional coffee grounds, coffee shops may be willing to provide you with additional grounds free of charge).
• Fresh manure: Poultry (7:1), Horse (22:1), Cow (18:1): Manure contains a high level of nitrogen, which is important for getting your pile decomposing quickly. Manure that is acceptable to use on compost pile include: cow, horse, chicken, rabbit, sheep, goat, and bat. Never use dog, cat, pig, or human manure as they can contain harmful parasites which can cause diseases in humans. Also, never use any fresh manure on your garden unless it has been composted first (composting can kill off many of the harmful parasites that could potentially be deadly to humans).
• Grass clippings (20:1): Grass clippings are very high in nitrogen and are best left on lawns where they will break down and decompose naturally to help feed the soil. If you do decide to use grass clippings in your compost pile, at first it is best to use them sparingly to prevent matting and clumping. Clumps and mats of grass tend to prevent air circulation in piles, and they can form slime which will release a rather unpleasant (but harmless) ammonia gas.
• Lake weed (19:1): If you have lake weed available in your area, it is an excellent source of nitrogen for compost piles.
• Plant cuttings (20 to 40:1): Can be an excellent source of nitrogen, as most plant cuttings are close to the ideal 30:1 ratio. Some plant cuttings (weeds) should be avoided if you are using the cool composting method. Temperatures in the cool method are unable to effectively kill weed seeds and potentially dangerous pathogens.
• Vegetables and fruit scraps (25:1): It is best to use uncooked material, as the oil often used in the cooking process will slow down the composting process, and may attract unwanted animals.

Brown Materials

This page contains ratios for brown to green compost. The ratios will be in the format of the following example: (brown number:green number).

• Eggshells (minimal impact): They take a long time to break down, but they provide calcium and are a good addition to compost piles.
• Hay (15 to 30:1): All types of spoiled hay make an excellent addition to compost piles.
• Leaves (50 to 80:1): Dead or dry are considered brown materials. View a list of some types of leaves to pay special attention to:
  • Walnut leaves should be avoided as they contain substances that inhibit the growth of many plants. Only use if they are thoroughly composted.
  • Oak leaves take a long time to break down because they are high in acid and levels of tannin. They are excellent for acid loving plants, but will take much longer to decompose than other leaves. If you wish to speed up the composting process for your main pile, separate out oak leaves and create a separate pile for them that can be used for plants that prefer acidic soils.
• Paper and Cardboard (150 to 200:1): Should be shredded first to speed up the composting process; avoid using glossy or highly colored papers; cardboard should be broken into small pieces or made into a slurry before it is added to the pile.
• Sawdust (400:1): Use small amounts and in very thin layers; never use pressure treated wood sawdust because it can leach arsenic into the soil.
• Straw (80:1): Provides less nitrogen than hay, but it will provide more than double the carbon. Straw takes longer to break down, but it is good in areas with clay soils as it helps open up the soil structure.
• Tea Bags (minimal impact): Either loose leaves or in a bag are fine.
• Wood Ash (25:1): Use sparingly to avoid high pH levels that will limit microbial activity, which aids in the composting process.