composting materials and bins 

Back Yard Composting

Getting Started

Back yard composting requires a little bit of space, a bin, and a basic understanding of the composting process.

Compost provides a long-term source of many nutrients not typically found in Colorado’s soils. Compost also helps your soil hold water longer.

Choosing a Compost Bin and Composting Area

There are many different systems and bins that will work for composting.

  • An open pile
  • A bin that you build yourself
  • A bin that you buy

If Possible, Locate Your Composting:

  • In a shady area to help keep it from drying out
  • Directly on the soil or grass, so compost critters have access to your pile
  • Near the kitchen and garden hose, so you have easy access for adding food waste, watering and turning

Building Your Compost Pile

A successful compost pile provides food for the compost critters (worms, bugs, fungi, bacteria, and other microorganisms) to break down. This food must be a balance of “green” (often wet) and “brown” (often dry materials).

  • Start your pile by adding a 4-6” layer of greens, then add a 4-6” layer of browns.
  • Add water and mix.
  • Continue to alternate layers of green and brown materials, followed by watering and mixing the pile.
  • Keep the pile as moist as a wrung out sponge.

Components of a Compost Pile

Food

  • Fruit and vegetable scraps and anything growing in your yard is potential food for compost critters. Air
  • Since all life needs a certain amount of air to survive, stir or turn your pile with a pitchfork regularly to keep air in the pile for compost critters and to keep your pile odor-free.

Temperature

  • The hotter the pile, the faster the composting. Your pile will heat up to approximately 90° – 140°F as it is composting.

Water

  • The compost critters work best if the pile is damp as a wrung-out sponge. In our dry climate, it means watering the pile with a hose and turning it to even out the moisture.

Particle Size

  • Chop materials into one to two inch pieces for faster composting, so compost critters have more surface area to attack.

Volume

  • Build your pile to the ideal size of 3´ x 3´ x 3´. Smaller piles will have trouble holding the heat, and piles larger than 5´ x 5´ x 5´ can collapse on themselves, cutting off the air to the compost critters at the center. These proportions are of importance only if your goal is fast composting. Slower composting requires no exact proportions.

Compost Critters

Once your ingredients are added to the compost bin, compost critters such as worms, bugs, fungi, bacteria, and other microorganisms will find their way into the bin to start the composting process. They work hard to break down organic matter into compost.

Compost Ingredients

Greens (Nitrogen-rich)   Browns (Carbon-rich) 
  • Fresh grass clippings
  • Garden trimmings
  • Fruit and vegetable scraps
  • Eggshells
  • Coffee grounds & filters
  • Tea bags
  • Manure (plant eaters only)
  • Dry leaves
  • Dried grass clippings
  • Hay or straw
  • Sawdust
  • Shredded paper
  • Finely chopped wood chips & bark
  • Old potting soil
Do not include in back yard composting
  • Meat, fish, poultry & bones
  • Dairy products, oils, grease & fat
  • Weeds with seeds
  • Cat and dog waste
  • Charcoal or Duraflame® ashes
  • Treated wood products
  • Cat litter  
Basic Rule: If in doubt, leave it out

Remedies for When Pile Is Not Composting

What if... Possible Cause Suggested Remedy
Pile not composting

Too dry

Too much brown matter

Add water until slightly damp and turn

Add fresh green matter (see chart above) and turn pile

Pile smells rotten and/or attracts flies Too wet and/or too many food scraps or lawn clippings Add brown material (see chart above), particle size of 1-2 inches will keep pile from matting down
Not enough air Turn it
Animals in pile Not maintaining or turning pile Bury food wastes and keep pile maintained and turned
Compost is damp and warm in the middle but no where else Pile is too small Collect more material and mix the old ingredients into the new pile
Center of the pile is dry Not enough water Moisten materials while turning the pile
Nothing is happening Pile won't heat up May need moisture and more greens such as coffee grounds to kick-start the process again

Using Your Compost

Compost is ready when it is dark brown, crumbly and when the ingredients are not recognizable. You can use compost in two stages: 

Finished Compost

  • Use as a soil amendment in gardens (anytime)
  • use as an ingredient for potting soil
  • place around plants, trees, or on lawns as a mulch or top-dressing

Partially Finished Compost

(all particles are not completely broken down)

  • Place around plants, trees, or on lawns as a mulch or top-dressing
  • Spread compost in your garden in the fall so it will enrich the soil over the winter to help your spring planting

 Related Links


Contacts

Resource Conservation Division

Staff Directory
720-564-2220
Email
Website

Boulder

Boulder County Recycling Center
1901 63rd St.
Hours: 8 a.m.-4:30 p.m. M-F
Map & Directions

Mailing Address

1901 63rd St.
Boulder, CO 80301

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