Following paper, food waste is the biggest part of our waste stream, comprising 14.5% of everything we throw away. Like almost everything that goes into our trash, food is recyclable. In fact, it is one of the easiest things we can recycle at home. The best way to recycle food waste is to compost it. Compost is a great resource that can help fruits and vegetables, flowers and even house plants grow better. It allows gardeners and farmers to use less water. Creating compost rather than putting food waste in a landfill has a big impact on global warming as well. When food waste breaks down in landfills, it produces methane, which is a greenhouse gas 72 times more potent than carbon dioxide. Any way you slice it, recycling your kitchen leftovers is a really good idea.

What is compost and how is it made?

Compost is decayed organic matter that has been broken down to the point where it resembles rich, dark-colored dirt. Within that crumbly substance are nutrients like potassium, nitrogen and zinc that plants can easily access and use to grow strong. There are beneficial bacteria that can fight off invaders intent on damaging plants and compounds that will improve soil quality. The list of compost’s advantages goes on and on. Even the U.S. Army uses it to detoxify soils contaminated with chemicals from explosives. A host of tiny organisms are responsible for making compost. They range from microscopic bacteria and fungi to common garden critters like worms, sow bugs and soldier flies. In a garden or forest, aerobic bacteria (or bacteria that need oxygen to survive) do most of the work. It is also possible to use anaerobic bacteria (those that do not require oxygen) to create compost. Anaerobic bacteria can harm people and plants, so they are used only in “in-vessel” composting facilities that require large machines to produce compost. The side benefit of using anaerobic bacteria is that they produce methane, which is a great fuel if it can be captured.

What kinds of food waste can be recycled?

It depends on whether you are composting food waste at home or sending it to a commercial facility. Composters using in-vessel systems can handle some materials home gardeners should avoid. Assuming you are composting at home, plan to put these types of food waste in your compost pile:

• Fruits and vegetables — this includes trimmings such as carrot tops, potato peels and stems from fresh herbs
• Bread, pizza crusts and other baked goods
• Pasta, oatmeal and other grain-based products (as long as they do not have too much oil on them)
• Crushed egg shells (these have the added bonus of helping keep compost from getting too acidic)
• Coffee and coffee filters
• Tea and tea bags

Add citrus sparingly, as it has natural antibacterial properties and can kill off beneficial bacteria if added in large quantities. These foods should go in the trash:

• Meat and seafood
• Bones
• Fats and oils
• Dairy products
• Hot peppers (sweet bell peppers are OK)

The other option for these hard-to-compost items is to send them to a commercial composting facility, although not all places accept them. Curbside food waste collection programs in Halifax, NS, Canada, and Portland encourage residents to include things like cheese and fish bones in their curbside bins. The program in Salt Lake City does not take them at all.

What else do you need to make compost?

Successful home compost piles have three main ingredients: nitrogen-rich materials like food scraps (known as “greens”); carbon-rich materials like newspaper and dry leaves (known as “browns”); and water. Get these three components in the right ratio, and you produce an environment where your beneficial organisms can get two additional things they need to produce compost: oxygen and a pile that is the correct temperature.

What is the right composting system for me?

You do not need a yard to produce compost. Even people living in apartments can compost successfully at home. People with space outdoors can simply build a compost pile, but most folks want something more contained, either for aesthetic purposes or to deter animals. The black Earth Machine compost systems have been very popular in recent years and work reasonably well. They are available at many Home Depot locations or locally owned garden stores. You can also build compost bins from pallets or scrap wood. The Oregon State University Extension Service has plans for building a three-bin compost system, as well as several other resources for home composters. If possible, avoid composters that require you to turn them. They may seem appealing, but they can get quite heavy and difficult to rotate. People without yards can keep worm bins in their homes. (Even if you have a yard, you might consider a worm bin because they produce some of the highest-quality compost out there.) A 35-gallon plastic tote is sufficient for most households. Store your bin in a closet or under the sink and feed your worms once or twice a week. You can purchase red wigglers (not night crawlers or other types of worms) online for about $40, or you can find someone with a farm or garden and dig them up yourself. If you are serious about setting up a worm bin, it is worth investing in a book called Worms Eat My Garbage by Mary Appelhof. It is considered the preeminent guide for worm bins. Other composting resources include your local extension office and the U.S. Environmental Protection Agency.