Compost is decomposed organic matter. It requires five basic ingredients:
- Carbon-rich materials (“browns”), such as leaves, straw, bark, paper, corn stalks, wood chips or sawdust
- Nitrogen-rich materials (“greens”), such as grass clippings, vegetable scraps or coffee grounds
- Microorganisms, such as bacteria, molds and fungi
Microorganisms, with the right amount of water and oxygen, break down carbon and nitrogen sources to create a final product that helps plants retain water and nutrients, and improves drainage and soil structure.
Any organic matter will decompose eventually, but for backyard composting, you want to only compost items that will decompose relatively quickly and that won’t attract animals.
- Vegetable & fruit scraps
- Coffee grounds & filters
- Tea & tea bags
- Grass clippings
A variety of ingredients — brown and green — are needed in the pile. The more varied the materials in your compost, the richer the finished product, filled with micro-nutrients and diverse, beneficial microbial life, will be. Here’s our list with special considerations and no-nos:
- Grass clippings
- Brush trimmings
- Manure (preferably organic)
- Any non-animal food scraps: fruits, vegetables, peelings, bread, cereal, coffee grounds and filters, tea leaves and tea bags (preferably minus the staples)
- Old wine
- Pet bedding from herbivores ONLY — rabbits, hamsters, etc.
- Dry cat or dog food
- Dust from sweeping and vacuuming
- Dryer lint
- Old herbs and spices
Need Prep or Special Time
All of these items can be added to compost, but if you just toss them into a normal heap, they may still be there, virtually unchanged, a season or two later. Be prepared.
- Shredded newspaper, receipts, paper bags, etc (any non-glossy paper)
- Tissues, paper toweling, and cotton balls — unless soaked with bacon fat, kerosene, makeup, or other stuff that doesn’t belong in the pile!
- Cardboard, egg cartons, toilet rolls
- Used clothes, towels, and sheets made from natural fabrics — cotton, linen, silk, wool, bamboo
- Old string & twine made of natural fabrics
- Pine needles
- Pine cones
- Saw dust
- Wood chips
- Nut shells
- Hair, human or otherwise
- Old, dry pasta
- Nut shells
- Corn cobs
- Pits from mangos, avocados, peaches, plums, etc.
- Toothpicks, wine corks
- Raspberry & blackberry brambles
- Long twigs or big branches
- Pet droppings, especially dogs & cats
- Animal products — meat, bones, butter, milk, fish skins
- Anything that might introduce disease or pests into my compost pile (and then into my garden) goes into the trash.
Compost is ready when the pile no longer emits heat, is dark in color, and crumbles easily. At a minimum, compost will take several months to form. Using smaller pieces of carbon and nitrogen sources, ensuring consistent moisture, and turning the pile regularly can help speed up the process. Avoid using unfinished compost on your garden, as it can actually be toxic to plants.
- Mix compost into the top several inches of soil of your garden.
- Use as mulch around trees and shrubs.
- Use as a top-dressing for lawns.
- Use as a substitute for part of the soil in your container garden.