What is Compost?
Compost is a dark, crumbly, earthy-smelling form of decomposing organic matter that can be easily made at home.
Approximately one-quarter of all refuse taken to our landfills is some type of organic waste. These materials do not decompose in a landfill because air and water are excluded. We can create a quality soil conditioner, while at the same time helping our community in its waste reduction efforts. Humus, the result of composting, retains water, adds valuable nutrients, and counteracts the extreme alkalinity of desert soils.
Ways Compost Can Be Used
What to Compost
- Soil enrichment for flower and vegetable gardens, trees, and houseplants.
- Part of a seed-starting mix.
- Liquid fertilizer by soaking a handful of compost in warm water for a few hours.
- Larger woody pieces can be used as a mulch. Because it is very rich and holds water, compost should be used sparingly around native plants.
Anything that was once a growing plant can be composted. Use approximately four parts carbon-rich material to one part nitrogen-rich material.
How to Start
(brown and dry)
(green and moist)
|Materials Which Should Not Be Composted
Dry grass clippings
Dried plant materials (trimmings, leaves, vines)
Wet grass clippings
Fresh plant clippings
Vegetable and fruit wastes
Barnyard manures and beddings
Alfalfa pellets from feed stores
Tea bags/coffee grounds
|Any kind of meat, grease, fat or oil. Any dairy product, especially cheese.
Dog and cat feces
Diseased or invasive plants, such as seeds or roots of Bermuda grass.
Oleander, Eucalyptus, and Tamarisk. These contain toxins that inhibit plant growth and must be used sparingly.
Any plant materials treated with herbicides or pesticides will prove to be troublesome unless the compost is aged at least a year.
- Select a place in the yard, preferably in the shade, out of the wind, and within reach of water.
- Assemble some type of bin to contain your composting organic matter. For little or no cost, a bin can be made from a circle of heavy mesh wire, old wooden pallets, or concrete blocks. Or, you can contact the city for a free recycled compost container at 480-350-8265.
- To ensure successful composting, it is a good idea to make your bin a minimum of 30 inches in each direction. This size insulates itself while allowing air to penetrate.
- Should you choose not to build a bin, commercially-made composting bins offer an easy and attractive way to recycle organic matter at home.
Steps to Success
Once the bin is constructed, stockpile dry organic materials and follow these simple steps:
- Shred or chop all materials into four-inch pieces or smaller in order to expose more surface area for the microorganisms to work on.
- Dig up two inches of soil where the bin will stand. Add a small layer of finger-sized branches to allow air to enter from below.
- Provide a mixture of about four parts dry or woody material (carbon-rich) to one part wet material (nitrogen-rich).
- Build the pile: Mixing all of your materials before adding them to the pile works best, but layering wet and dry material alternately also produces good results. Each layer should be no more than four inches thick. Occasionally sprinkle in soil or manure to provide the bacteria needed to start decomposition. If using food waste (vegetable scraps only) be sure it is buried under other layers to avoid flies.
- As each layer is added, sprinkle lightly with water, ensuring moisture throughout the pile. The interior should be moist, not wet. During periods of heavy rain, cover with a tarp.
- Once your container is full, top off the pile with two inches of soil.
- As decomposition takes place, the pile will begin to heat up. Interior heat can reach 160 degrees Fahrenheit.
- Before the pile has cooled down to the ambient air temperature, reactivate it by allowing more oxygen to penetrate the pile. Simply turn the material into a second bin, or use a turning fork to thoroughly mix the pile. It may be necessary to add more water or green plant materials.
- Note: Our process ensures compost in two to three months. You may wish to turn your pile less frequently, although the composting process will take longer.
- Repeat these steps as needed until the mixture is soft, dark, and crumbly.
- To use the finished compost, sift on a 1/2 inch mesh screen to remove large, semi-decomposed pieces. Return these to the bin for further breakdown.
Take a Closer Look
|The compost has a bad odor
||Not enough air and/or too wet
||Turn it, adding dry materials if too wet
|The center of the pile is dry and little or no decomposition is taking place
||Not enough water
||Add green materials and sprinkle with water while turning it
|The compost is damp and warm in the middle but nowhere else
||Pile is too small
||Collect more material and mix with the old ingredients to form a new pile at least 30" X 30" X 30"
|The compost is damp and sweet smelling, but will not heat up
||Too little nitrogen
||Mix in a good source of nitrogen such as green grass clippings, bloodmeal, ammonium sulfate
Nature has its own very effective composting program using millions of microscopically small organisms (bacteria and fungi). Were it not for everyday decay, we would be walking on mile-high piles of debris. Earthworms, pill bugs, insects, and centipedes all play a part in breaking down organic materials, and by providing care, we can speed up the process nature performs itself.
In order to live and work within a compost pile, microorganisms must have oxygen, water, nitrogen, and carbon. Woody and dry materials are rich in nitrogen, and supply protein. The microbes produce heat as they grow and multiply. If you provide the proper ratio of carbon-rich to nitrogen-rich materials, make a large enough pile, and ensure that moisture and aeration are adequate, you will produce a hot, fast compost. A small pile will not heat up, but will decompose in time as well.
Food Waste Composting for Small Spaces
-- Combine chopped kitchen wastes with equal amounts of water in your blender or food processor. Bury this "soup" around the outer edges of plants or place directly into a garden trench. Fill with soil and water well. Seeds or transplants can be added immediately.
-- For placement on a shaded balcony or in a carport, use a wood box with small drainage holes in the bottom and, if possible, a tight-fitting lid. As an example, a 2' X 2' X 8" box will compost kitchen scraps from two people, assuming four pounds of garbage per week. The box must be filled with moistened bedding make from a mixture of shredded cardboard, dried leaves, and/or peat moss. Add at least 100 red wiggler worms. Dig chopped or blended scraps into a different place each time. A fitted piece of carpet works well as a cover, retains moisture, and helps to keep temperatures below 85 degrees. Remove the compost every three months. Refill the box and transfer the worms.
A bottomless box can be placed directly on loosened soil. Fill in the same manner. After three months lift the box and leave behind a fertile bed of compost. Start again in a new place. Keep shaded during extreme heat.