Compost, Home or Away
Good for the garden, good for the planet
Here in California, the weather is cooling off, the leaves are turning brown, and thanks to some landmark legislation, compost is finally getting its moment in the sun.
As organics diversion and commercial organics recycling laws are implemented statewide, local jurisdictions are ramping up “green” recycling programs, including residential curbside pickup. From a materials management standpoint, this is great news, since we need to divert large volumes of organic material from our landfills as quickly as possible to reduce greenhouse gas emissions.
More than 13 million tons of organic material went to landfills in 2014. If 1 million tons of that material had instead been composted, more than 216,000 metric tons of CO2 equivalent greenhouse gas emissions from landfills would have been avoided.
If you don’t live in a jurisdiction that will pick up your green waste—or, if you do any type of gardening and would typically end up buying compost—you might consider home composting, if you aren’t doing so already.
Regardless of whether you compost your material yourself or let your local waste management company take care of that for you, the benefits are significant:
- Compost helps soil retain water, so less water is required to grow plants, whether they’re ornamental or agricultural.
- Compost enriches soil with nutrients, which makes plants healthier and increases crop yields while reducing or eliminating the need for additional fertilizer.
- Diversion from landfills means organic material won’t be decomposing and generating methane there.
CalRecycle has several excellent webpages on home composting, starting with a basic primer, including instructions, links, and troubleshooting tips. The Natural Resources Defense Council also has a nice composting wepbage.
Here are the quick-and-dirty directions:
- Start with some sort of container, preferably at least 3 feet by 3 feet by 3 feet (one cubic yard).
- Add “brown” material such as dried leaves, clean straw or hay, or shredded paper products like newspaper and paper towels (“brown” is “high in carbon”). This bottom layer should be at least 4 to 6 inches deep.
- Add “green” (“high in nitrogen”) material like fruit and vegetable leftovers, used coffee grounds and filters, and grass clippings. This layer should be about half as thick as the “brown” layer.
- Use a pitchfork or shovel to mix the layer and aerate the pile.
- Add water until the pile is the approximate consistency of a wrung-out sponge.
Depending on how diligent you are about your carbon-nitrogen ratios, moisture level, and aeration, (i.e., whether you are a “gourmet” composter or a “casual” composter, according to our primer), sooner or later your organic material will turn into rich, dark, earthy-smelling compost. While the pile will naturally heat up in the process, careful maintenance can result in temperatures of 120 to 140 degrees Fahrenheit, which will kill most weed seed and speed up decomposition, so compost could be ready in two to three months.
The regular application of “brown” and “green” material, regular watering, and mixing to add oxygen to the pile, are what basically differentiate composting from the smelly, greenhouse-gas-emitting process that occurs when organic material breaks down in landfills.
For a more detailed explanation of what’s happening in your compost bin, see LiveScience’s piece titled “How Do Compost Piles Work?”
Here are some more compost-related links on CalRecycle’s website:master gardener program if you have specific questions or to meet like-minded gardeners. Occasionally master gardeners have composting workshops or demonstrations at local events like farmers markets. Give it a try!