How to Compost

The organisms that make compost need food (carbon and nitrogen), air, and water. When provided with a favorable balance, they will produce compost quickly. Other factors affecting the speed of composting include surface area/particle size, volume, and temperature.

Volume


Volume is a factor in retaining compost pile heat. The recommended size for a home compost pile is no smaller than 3 feet square and 3 feet high, and no larger than 5 feet square and high. Homes located on lakes or in windy areas may want to consider slightly larger piles measuring 4 feet square and high; smaller piles will still decompose material, but they may not heat up as well, so decomposition will take longer.

Start your pile with a thick layer of coarse carbon material like chipped brush, wood chips, chopped corn stalks, or shredded leaves, to build in air passages. Add thinner alternating layers of brown (carbon) and green (nitrogen) materials with a shovelful of soil on top of each layer. Shredding leaves or running over them with a lawn mower will shorten composting time. Be sure to bury food scraps in the center of the pile. Add water as you build the pile if materials are dry.

Aim for an optimum moisture level in your pile that feels like a damp, wrung-out sponge. Achieve this by mixing in more water (or wet nitrogen materials) and dry carbon materials, as needed.

High Nitrogen ‘Green’ Ingredients


  • Grass clippings
  • Weeds
  • Food scraps:
  • fruit, vegetables, coffee grounds, tea bags, crushed egg shells
  • Manure (cow, horse, chicken, rabbit)
  • Seaweed
  • Alfalfa hay/meal
  • Blood meal

High Carbon ‘Brown’ Ingredients


  • Autumn leaves
  • Chopped straw
  • Shredded paper towels, napkins, bags, plates, coffee filters, newspaper
  • Chopped cornstalks
  • Wood chips
  • Saw dust
  • Pine needles

Aeration


Aerate your pile weekly by turning it with a pitch fork or spading fork. In reality, most composters turn their pile less often, which makes decomposition take a longer time. After about 2 weeks you will notice your pile settling, which is a good sign that your pile is decomposing. You can add fresh material to your compost pile whenever they become available-this also allows you to aerate the pile and add water if needed. A good rule of thumb is to mix in 1 part nitrogen materials with 3 parts carbon materials; the ideal carbon to nitrogen ratio in a compost pile is 30:1.

Smaller Sizes


Although it is not required, reducing materials into smaller particle size will speed the rate of decomposition because this makes the surface area more available for microorganisms to work. Organic materials can be chopped, shredded, split, bruised or punctured to increase their surface area. Don't ‘powder' materials because this will compact and impede air movement in the pile.

Temperature


Temperature in your compost pile is an important factor related to air and moisture levels. As microorganisms work to decompose the compost, they give off heat, which increases pile temperatures. Pile temperatures between 90-140 degrees indicate rapid decomposition. Lower temperatures signal a slowing in the composting process. High temperatures above 140 degrees reduce the activity of most organisms. Compost thermometers are available from garden supply companies and can be used to monitor your pile. Another method is to stick your fist into the pile interior. If it feels uncomfortably warm or hot during the first few weeks of composting, that is a good sign that everything is fine. If the pile temperature is similar to the outside temperature, increase the composting activity by adding nitrogen rich material and turning the pile.

How to Tell When Compost is Ready


Compost can take anywhere from 3-4 months to 1-2 years to finish and be ready to use, depending on how well it was managed. Compost is ready to use when it is dark, crumbly and fluffy with an earthy odor. It should not be moldy and rotten. The original materials that went into the pile should no longer be recognizable, except for some woody pieces (which you can throw into your next pile). The temperature of finished compost should be the same as the outside temperature, and the material should not reheat. You will see earthworms and other insects now that the temperature is lower. Once your compost is finished, let it sit for 3 weeks to make sure the decomposition process has stabilized.

Applying Compost to Garden


Recommended application rate of compost is 1-3 inches into the top 4 inches of garden soil about one month before planting. Compost can be applied as a top dressing in the garden throughout the summer. It is excellent for reseeding lawns, and can be spread ¼ inch deep over the entire lawn to rejuvenate turf. With perennials (and annuals), every time you add a new plant to the garden or divide an existing one, add compost to the planting hole. Make a seed starting mix with fine textured compost (use ¼ or ½ inch screen to get fine texture) by mixing 2 parts compost + 2 parts peat + 1 part vermiculite (pre-wet). Make a potting soil mix with equal parts compost, sand and top soil.

Compost Tea


Make compost tea to fertilize your plants - it is especially good for new transplants and young seedlings. To make compost tea fill a burlap sack or pillow case with finished compost and secure the open end. Place in a tub, barrel, or watering can filled with water. Agitate for a few minutes and let steep for a few days. Water will leach out nutrients from the compost and the mixture will take on the color of tea. Spray or pour compost tea on and around plants. You can use the bag of compost for several batches. Afterwards, simply empty the bag's contents onto the garden.

Winter


Most people let their pile shut down during the winter months, and reactivate it in the spring. If you want to keep your pile active in the winter, you will need to insulate it on the top and sides to prevent freezing. Or you can store your food scraps in the freezer during the winter and add them to your pile in the spring when you reactivate your pile.

Vermi-composting with a worm bin and worms (species Eisenia Foetida) is a great way to make nutrient rich compost and utilize all your food scraps and newspaper during the winter months.