Garden Tips

From Katie Burki, Lakewold's Garden Manager

Urban Composting - Creating a Three Bin Compost System . . .

They seem like the most efficient way to go with two bins used for materials and the final bin used for curing or cured compost. Once built, the success of a compost pile relies on a balanced system. This balance is created by having the right amount of food, water, and air in the system to feed microbes that in turn create heat, and assist in breaking down the materials. Compost piles with favorable conditions can reach 120 to 150 degrees very quickly. At this temperature most of your weed seeds will be killed and as the pile starts to cool, lower temperature organisms complete the decay process.

Bulking agents

• Wood chips and/or sawdust
• Grass hay
• Wheat straw
• Shredded paper

Bulking agents supply the porous material that keeps air in the pile. If your pile has a bad “rotten egg” smell to it, it probably does not have enough bulk material incorporated.

Energy materials (fuel and supplements)

• Grass clippings
• Fresh Dairy, chicken or rabbit manure
• Fruit and Vegetable waste
• Garden trimmings

The energy materials provide the nitrogen and carbon in the mix. These are needed for the microbial growth.

Balanced materials (fiber)

• Ground tree and shrub trimmings
• Horse manure and bedding
• Deciduous leaves

The balanced raw materials contain a little of each above and help with the overall balance of the pile.

Assembly directions:

Prepare - Grind, cut, smash or chop your materials into sizes suitable for microbes to eat. The smaller the size the more tasty they are. For a good, hot pile anything around ¼" is suitable.

Mix - do not layer! Add new ingredients to the center of the pile. (This will also keep pests away).

Size - bigger is always better! The bigger the pile the hotter it gets (that’s a good thing)!

Moisture - It should be moist, but not wet! Piles will need supplemental moisture in dry
summer months. During the winter rain it might need to be covered or located in a protected area to keep strong rainfall out of the mixture.

Aeration - For fast decomposition, the microbes need oxygen. As the pile decomposes it settles, so turning the pile and adding more bulking agents helps keep the oxygen flowing and the microbes eating.

Nutrients - Compost needs vitamins, too (nitrogen, phosphorus, sulfur). You can add diluted liquid fertilizer or alfalfa meal.

Backyard composting is a win-win situation. It reduces the flow of waste to our local landfills, and it produces valuable organic matter for our gardens. I even see a third benefit: composting feeds starving microbes that have a tough lot in the city these days, with the recession and all. For more information on construction and materials visit http://www.piercecountywa.org/composting.

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