Gardening How-to Articles

What and How to Compost

Left on its own, all organic matter will eventually break down into nutrients that can be absorbed by plants. Composting is simply a way of helping things along by including the right ingredients in the right proportions under optimal conditions. Follow these guidelines to produce compost faster and without odor or pest problems.

What can I compost?

Most plant-based organic material, including yard waste and fruit and vegetable scraps, can be composted at home under the right conditions.

You can put these materials in your backyard bin or pile:

  • leaves and brush
  • plant cuttings
  • grass clippings
  • fruit scraps
  • breads and grains
  • coffee grounds and filters
  • tea bags
  • eggshells
  • wood chips
  • sawdust
  • wood ash
  • old potting soil
  • cut flowers
  • food-soiled paper (napkins, paper towels)

Don't add these materials to your compost:

  • meat scraps
  • fish scraps
  • dairy products
  • fats or oils
  • grease
  • dog feces
  • kitty litter
  • weed seeds
  • charcoal ash
  • nonorganic materials

Layering and Mixing

Aim to have roughly equal parts “green” (nitrogen-rich) and "brown" (carbon-rich) materials. All organic materials contain carbon and nitrogen in varying proportions. In general, wet, or green, materials such as grass clippings, food scraps, and plant cuttings contain a higher proportion of nitrogen than dry, or brown, materials such as wood, paper, and autumn leaves.

Greens (high nitrogen):

  • grass clippings
  • plant cuttings
  • fruit and vegetable scraps
  • coffee grounds

Browns (high carbon):

  • fallen leaves
  • twigs
  • wood chips
  • sawdust
  • used napkins and paper towels
  • soil or finished compost

To create ideal conditions for composting, try to include roughly equal parts of both and layer or mix the materials in your pile. A pile with more browns will still turn into compost, but it will take longer. If you add too many greens, your pile may generate odors.

To avoid odors or pests, bury food scraps under browns such as leaves, brush, wood chips, or finished compost.

Air and Water

The microorganisms in compost need oxygen and water to survive.

To make sure that air can penetrate to the center of your pile, it should not be larger than 5 feet high by 5 feet wide. You can also layer your pile with coarse materials to help air circulation; or you can aerate it by turning or mixing it periodically. Turning requires extra effort, but will accelerate the compost process.

Your pile should be about as moist as a wrung-out sponge, not soggy. You may want to water it periodically during a dry spell or after adding large amounts of dry materials.


You can make compost in as little as three months, or the process could take as long as one year. Each of the following measures will speed the composting process:

  • Layer your pile with the proper proportion of greens and browns.
  • Turn your pile and keep it moist but not soggy.
  • Chop materials such as branches and grapefruit rinds into small pieces before adding them to your pile.

Using Compost

If you have ever used peat moss, wood chips, manure, or topsoil to amend your garden, then you already know how to use compost. Mix compost into flower and vegetable beds; blend it with potting soil to revitalize indoor plants; or spread it on your lawn as a fertilizer. Use coarser compost as a mulch around trees and shrubs.

Note: If you make compost with plant cuttings or grass clippings that have been sprayed with pesticides, avoid using it on edible crops.


  • Betty September 22, 2015

    Thank you for the compost info. Question: Is it OK to add to my compost bin food from the table that has been cooked in oil i.e., EVOO, coconut oil? I have been composting for over 25 years and wonder if I’m doing the wrong thing.

  • Gina M. August 10, 2015

    I am new to composting and am looking forward to starting my first batch. I live in a condo with a fenced in patio (basically no backyard just a cement patio). Is it still feasible to start/maintain a compost bin without a yard to help encourage the compost process? Is there anything special I should do to facilitate the compost process since there won’t be any grass to surround the compost bin?

  • Candace July 26, 2015

    Can I put blackberry bush clippings in my compost barrel, or will that not break down?

  • Sandy G June 19, 2015

    I recently started composting. The problem I’m having are gnats! What am I doing wrong?

  • NYC Compost Project June 16, 2015

    Dear Laertner: It sounds like the setup you have is what we would call a tumbler. Tumblers are effective in creative relatively quick, small batches of compost. When using a tumbler, add equal amounts of browns and greens; otherwise you might end up with either a smelly or an inactive pile. Be sure to thoroughly chop them up to accelerate the decomposition process. When your container is full, you can let it sit and continue to turn the tumbler. (As tumblers become filled with material they can be a little difficult and heavy to turn.) Check on the material periodically until you have a dark, earthy smelly soil and voilà—you have compost!

  • Cheryle May 6, 2015

    I’m new to composting and am tight on $$. Can I place my green/brown mix on plastic outside and cover it with plastic (ex. garbage bags)? Or should I put in on the ground and cover with the bags?

  • laertner April 26, 2015

    I have made my own composter out of a 30-gallon barrel, and it can spin. I am not sure how to start it. We normally dig compost in the garden and have had problems with dogs and other animals digging things up. So we wanted to use a bin. Can you tell me how to get started?

  • BBG Staff February 26, 2015

    Vijaya: Here, “organic” means anything derived from living matter. Any such materials that will decay during the composting process will work. That being said, the fewer residual pesticides from garden clippings or kitchen waste the better for your compost, especially if it is intended for growing edibles.

  • Vijaya February 24, 2015

    In the article, it says put organic fruit and veggie scraps—does that mean we can only compost organically grown veggies and fruit waste?

  • Vijaya February 24, 2015

    Nice article. I have started indoor composting with a Kambha composter bin with pots, one above the other, in southern India. Weather is quite hot here. I usually put fruit, veggie scraps, and leftovers along with homemade yogurt occasionally and through thin layer of paper cuttings above every layer of green. My top pot seem moist enough and shrinks down the waste pretty good. The two bottom pots, which have half-composted material, dry out very quickly, hence, the composting process takes longer. Is it recommended to spray some water to bottom two pots occasionally, or should they be left to take their own time to compost? Is there any other way to speed up composting?

  • Peggy Carrigan November 16, 2014

    My parents actually put all our scraps and coffee grounds, etc., in our garden, so I have always been a composter. I never knew about layering with the green/brown etc.. so that is good to know. I want to start a bin outside so I can plant a nice garden next spring. What is the best kind of container? Plastic? Also, one more question, if it is an outside bin, you mentioned the worms and bugs get in on their own—how do they get through plastic or aluminum? Thank you!

  • BBG Staff September 24, 2014

    Kirsti, cat feces are definitely a composting no-no. Cats, dogs, and other animals—pets or otherwise—may carry parasites and other pathogens that can be harmful to humans if ingested.

  • Lorien Deats September 24, 2014

    I am starting my first compost. I would like to start indoors, but it seems outdoors would be the easiest by the comments. Just not quite sure how to get the composting started. I have a small container in mind. If I put this outside, should it be covered or protected from weather, or should I start inside as I originally intended (I’m afraid it will smell too much)?

  • Kirsti August 17, 2014

    You only mentioned dog feces being a problem. Are cat feces OK to put in compost? Great articles; I have learned so much! Thanks.

  • Terry July 19, 2014

    This is my first time doing composting. Do you have to have a lid on your container? Can you put in all skins from all fruit?

  • BBG Staff October 1, 2013

    No need to add worms to an outside bin, Carmen: If the browns, greens, and moisture levels are right, the worms will move in on their own and help the composting process.

  • carmen engel September 30, 2013

    I am making my first compost. It is in a bin but outside. Do I need worms also? Thanks.

  • BBG Staff September 18, 2013

    Sure, Kim: As long as they aren’t animal-based material, the moldy scraps are fine. The mold means they are already decomposing, and turning them into the pile with the rest of the compost will speed up the process.

  • kim campbell September 18, 2013

    Is it ok to put moldy scraps into the compost pile?

  • Lucia Pascone June 7, 2011

    We started a pile of autumn leaves mixed with some grass clippings and kitchen scraps in a large area in our yard in Delaware County hoping it would decompose in time for late spring planting. The proportion of brown to green was not right and then the snow of winter months made it a wet mass. Can we still save our attempt and speed up the decomposition process?


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Image, top of page: NYC Compost Project Hosted by Brooklyn Botanic Garden