Composting at Home: The Basics
Composting is a great way to reduce the amount of waste your household sends to landfills. In fact about 28% of the average household waste stream in America is compostable.
While many households have already adopted recycling practices for materials like paper, plastic, metal, and glass, it's important to note that food and yard waste is often overlooked. Implementing compost practices in your home can be a powerful solution for reducing waste and mitigating your environmental impact.
Why should my household compost?
When we grow food, we take nutrients from the ground. When we send our food scraps to the landfill, we miss an opportunity to put those nutrients back into the soil.
Composting converts organic waste into a nutrient-rich amendment that feeds the soil, which creates a circular or closed loop system that allows us to have nutritious food for future generations.
Reduce Greenhouse Gas Emissions
As materials decompose in landfills, they release harmful greenhouse gasses such as methane and carbon dioxide and can leach harmful chemicals into surrounding soil and groundwater.
Landfills are the third-largest source of anthropogenic methane emissions which are 25 times more potent than carbon dioxide at trapping heat in the atmosphere. However, by choosing to compost organic materials instead of disposing of them in landfills, you can reduce the greenhouse gas emissions from your home.
According to the U.S. Environmental Protection Agency (EPA), food waste and yard trimmings make up about 28% of the U.S. municipal solid waste stream by weight. By composting your organic waste, you can divert it from the landfill and turn it into a valuable resource for your garden or yard.
Improve Soil Health
Compost is a natural soil amendment that can improve the health of your garden soil. It provides nutrients to plants and improves water retention of the soil, which can lead to healthier, more productive plants. Compost also promotes the growth of beneficial microorganisms in the soil, which can help to suppress plant diseases and pests, and reduces the need to use chemical fertilizers.
For more on the benefits of compost, check out this article.
What are the basics of composting?
Compost is a natural soil amendment made from a mixture of organic materials like food waste and yard trimmings. When added to the soil, it increases the amount of nutrients available to plants to up-take.
Feedstock and Nutrient Balance
Composting requires a proper balance of “green” organic materials and “brown” organic materials.
Green organic material includes grass clippings, food scraps, and manure, which contain large amounts of nitrogen.
Brown organic materials include dry leaves, wood chips, and branches, which contain large amounts of carbon but little nitrogen.
You typically need a higher ratio of brown elements (carbon) to green elements (nitrogen). Obtaining the right nutrient mix requires experimentation and patience and is part of the art and science of composting.
Grinding, chipping, and shredding materials increases the surface area on which microorganisms (microbes) can feed. Smaller particles also produce a more homogeneous compost mixture and improve pile insulation to help keep up optimum temperatures (see more below). But if the particles are too small, they might prevent air from flowing freely through the pile. It's all about balance!
Microbes living in a compost pile need enough moisture to survive. Water is the key element that helps transport substances within the compost pile and makes the nutrients in organic material accessible to the microbes. Organic material contains some moisture naturally, but moisture also might come from rainfall or intentional watering.
Turning the pile, placing the pile on a series of pipes, or including bulking agents such as wood chips and shredded newspaper can help to aerate the pile (i.e. provide oxygen flow).
Aerating the compost pile allows decomposition to occur faster than anaerobic conditions (i.e. the lack of oxygen). It's important to not that too much air can dry out the pile and impede the composting process, so finding the right balance is imporant.
Microbes require a specific temperature range for optimal activity. Certain temperatures encourage rapid composting and destroy pathogens and weed seeds.
Microbial activity can raise the temperature of the pile’s core to at least 140° F. If the temperature does not increase, anaerobic conditions (i.e. rotting) occur. Controlling the first four factors mentioned above are key to keeping the pile at the proper temperature throughout the various stages of decomposition.
What are the different methods of composting for a household?
There are a variety of different composting methods. Below is a list of the more common composting methods:
Home and Garden
The most common method for composting involves creating a small pile at a community garden or home backyard. It's a good method for breaking down yard trimmings and small amounts of food scraps.
However, meat, dairy, bones and large quantities of food scraps are not recommended for home and garden composting because the pile typically does not reach sufficient temperatures and can potentially attract pests if not managed properly.
Vermicomposting relies on a species of worms, red wigglers, contained in bins to feed on food scraps, yard trimmings, and other organic matter to create compost. The worms break down this material into high quality compost called castings.
One pound of mature worms (approximately 800-1,000 worms) can eat up to half a pound of organic material per day! The worm bins can be sized to match the volume of food scraps that will be turned into castings, and it typically takes three to four months to produce usable castings.
The other byproduct of vermicomposting known as “worm tea” is used as a high-quality liquid fertilizer for houseplants or gardens.
Aerated (Turned) Windrow Composting
Aerated, or turned windrow, composting is best for large volumes of food waste generated by entire communities or high volume food-processing businesses (e.g., restaurants, cafeterias, coffee shops).
This type of composting involves forming organic waste into rows of long piles called “windrows,” and aerating them periodically by either manually or mechanically turning the piles. The ideal pile height is between four and eight feet with a width of 14 to 16 feet. This size pile is large enough to generate enough heat and maintain temperatures, but small enough to allow oxygen flow to the windrow's core.
Because of the temperature the piles can achieve (up to 160 degrees!), windrow composting can break down meat, fish, dairy, and bones as well as compostable products (cups, plates, utensils, etc. made from plants or plant-based plastics). The windrow method is what CompostNow uses at its commercial compost facility.
This method involves feeding organic materials into a drum, silo, concrete-lined trench, or similar equipment which allows good control of the environmental conditions such as temperature, moisture, and airflow.
The material is then mechanically turned or mixed to make sure it's properly aerated. The size of the vessel can vary in size and capacity. While in-vessel composting can process the same variety of material as windrow composting, the equipment can be expensive and require technical expertise to operate.
This method can produce compost in just a few weeks, however it takes a few more weeks or months until it is ready to use because the microbial activity needs to balance and the pile needs to cool. Just like a fine wine, compost gets better as it matures.
Compost Service Provider
If you don’t have the space, time, or resources to compost on your own, a compost service provider can be a great option for your household. The main benefit of a service provider is that they do all of the hard work for you and you can rest easy knowing your waste is being properly composted.
Compost service providers typically come at a cost depending on the area you live. Because the organic recycling industry is still new, compost is not subsidized like other waste streams such as landfilling and recycling, but at CompostNow, we believe it is critical infrastructure that should be invested in and developed.
Community Compost Programs
These programs are typically developed by municipalities or public entities and are open to the community at little to no cost. While we would like to see a future where all communities are compostable in this way, there are a lot of operating and logistic barriers that prevent public entities from scaling this type of program.
A key challenge is the development of industrial compost facilities that can accept and properly manage large volumes of food and organic waste. The good news is that the demand for this type of infrastructure is increasing, and there are more federal, state, and local initiatives supporting the development of these operations.
What can my household compost?
What your household can compost varies depending on your compost method. With most methods of composting like at-home and community gardens, it is safe to include the following:
Fruit and vegetables
Yard or grass trimmings
If you’re composting with a service provider or compost facility operator, you can often compost a wider range of organic materials, including:
The items listed above
All food scraps including meat, dairy, and bones
Oils and fats
Cardboard (including pizza boxes)
BPI Certified compostable plastics
BPI Certified compostable products like coffee cups and cutlery
BPI Certified compostable to-go food packaging
Bamboo or wood products
It’s important to note that your service provider or local facility may have additional rules or regulations about what they can and cannot accept. These are often provisioned by external regulators, so it’s important to familiarize yourself with the rules in your area.
Composting offers a wide range of benefits for households, from reducing waste to improving soil health and biodiversity. It's an effective way to support a sustainable lifestyle and protect the environment for future generations.