As you feast, gather, and celebrate, waste can pile up all too quickly during the holiday season. Strategic shopping, creative leftover reuse, and mindfulness around excess can help prevent food waste, but food scraps are pretty much an inevitable part of the process.
That’s why it’s a great time to dig deep into the art and science of compost. Guest writers Carola Di Poi and Thomas Smith will help you unpack the fundamentals and formulas behind composting so you can start or level up on your composting journey.
Food waste is a huge problem in the United States, and it has a significant environmental and climate impact. Greenhouse gas emissions are caused by food waste being deposited in landfills and not actually decomposing into usable material. And when food is wasted, the associated production (land use and human labor), transportation, and processing is also “wasted,” contributing to additional greenhouse gas emissions.
The good news is that food waste can be reduced by doing a few simple things to help keep it out of landfills. While companies have significant room for improvement with regard to the overall contribution of food waste, consumers can take a few simple steps to reduce their individual and family food waste. One approach is through compost. Compost is the process by which organic matter breaks down through the composition and respiration of soil organisms like bacteria, fungi, and insects into a nutrient-dense end product, humus, beneficial to both soil and plants.
Composting food waste
Composting can help reduce food waste and return carbon to our soil. Food waste can be composted at home, and there are a variety of products available to help you start your own composting journey. Community compost options may exist in your area, and these organizations can assist you in composting your home or neighborhood’s food waste. In Pasadena, a local nonprofit, Compost Culture, collects food waste from restaurants and other businesses, which is then composted at Huntington Botanical Gardens.
Why compost?
Composting can significantly reduce food waste while also providing fertilizer for your own gardens. When food waste is composted, carbon is returned to our soils which are the largest terrestrial carbon sink/storage. This can help remove carbon from our atmosphere while providing benefits to our soil. And you may see monetary savings because you will not have to buy compost separately.
How does compost work?
During the composting process, organic matter is broken down into simple organic molecules by a complex community of organisms including bacteria, fungi, nematodes, protozoa, worms, ants, and many others. These require oxygen, water, and a source of chemical energy (organic matter) to feed on the nitrogen and carbon inputs, breaking them down and releasing valuable plant nutrients.
There are many different types of composting methods: piles, containers, tumblers, and even using worms to speed up decomposition. This will discuss the simplest composting method which does not require worms, or special formulas.
What can be composted?
Yard trimmings, paper, cardboard, raw plant-based food waste, egg shells, coffee grounds, unbleached coffee filters, and tea bags can all be composted. Fruits and vegetable scraps
What cannot be composted?
Diseased or weedy plants, glossy paper or paper with lots of ink, cardboard with shiny plastic or ink, food waste that has been cooked or contains oil, plastic, glossy tea bags, and staples all CANNOT be composted.
The compost formula
There are many ways that composting is discussed in terms of managing the content that goes into a compost pile or bin. Two important factors in creating high-quality compost are the ratio of carbon to nitrogen and the amount of air present in the compost pile. This is important as the fungi and bacteria that will break down our food waste need both carbon and nitrogen and air to respirate.
The nitrogen-to-carbon ratio is also known as the green-to-brown ratio. Greens are wet materials that were recently living, such as grass clippings, coffee grounds, and fruit and vegetable scraps. Browns are dry materials like newspapers, undyed paper/cardboard, egg cartons, pine needles, and dry leaves.
The wet-to-dry materials ratio also provides an important aspect of composting. Wet material reduces the amount of air within the compost. If too much wet material is added, this can lead to anaerobic decomposition, making compost piles smell. It’s important to have a mix of both wet greens and dry browns for optimal composting.
Getting started is simple. One of the very first steps is to begin collecting your food scraps in a container and storing it in your freezer. This gives your compost a head start as you will be introducing water to the mix during the thawing process, and you’ll be breaking down the cell walls of the scraps, making them easier to decompose. This will also eliminate fruit flies and any bad smells that may occur when scraps sit on your kitchen countertops.
Resources
There are many ways you can make the most of compost at home, through a community hub like LA Compost, or at an industrial scale. Although it can be challenging to try something new, we hope that compost will be a fun and rewarding way to reduce your food waste!
- How to compost at home
- Community compost: Los Angeles resources, Start your own
- Industrial compost: Industrial-scale composting laws and availability varies from region to region, so be sure to check with your local sanitation program. For California residents, CalRecycle is a great resource.
Carola Di Poi is a garden educator and photographer based in Los Angeles, currently working in the experiential and teaching gardens at the Huntington Library. Formerly with Imperfect Foods, World Central Kitchen, LA Compost, and LA Más, she has worked alongside underserved communities and their food systems in Los Angeles and abroad for the last 15 years.
Thomas Smith is the Manager of the Experiential and Teaching Gardens at The Huntington Library, Art Museum, and Botanical Gardens.