Small Scale Composting
Organic waste comprises an estimated 20-40% of the solid waste stream that ends up in landfills. Organic matter breaks down slowly in landfills due to limited oxygen, which can contribute to methane gas production. Enter stage left: compost.
Compost is the rich, black remnant of organic waste such as kitchen scraps combined with “brown” matter (i.e. soil, leaves); the result is beautiful fertilizer for your garden. Intentionally composting accelerates the natural process of the breakdown of organic matter. Composting reduces landfill waste, saves you from using chemical fertilizers, and introduces beneficial organisms to your soil.
How it works
Essentially, composting comes down to balancing two components: nitrogen and carbon. You’ll often hear gardeners and compost enthusiasts refer to this as “green” matter and “brown” matter, respectively. Green matter includes materials like food scraps and grass clippings, while brown matter encompasses things like leaves, straw, and paper.
For best results, you are looking for a carbon (C) to nitrogen (N) ratio (C/N) of 30:1, but small batch composting should aim for a C/N ratio of 25:1. These figures are based on weight, which is hard to judge at sight, so aim for approximately 30-40% green material. The Urban Garden Center provides a convenient list of common nitrogen and carbon-rich materials for your compost bin.
Particle size – The smaller the raw material size, the more surface area you’re providing for the microorganisms to feast upon. This is particularly important when composting in smaller batches, as smaller particles speed up the composting process. Aim for shredded pieces no more than one inch in width.
Air – Oxygen is very important to the microorganisms that help break down compost materials. Frequent aeration is key when small batch composting; aeration is made simple with a tumbler-style composter that allows you to aerate regularly.
Temperature – 50 degrees F is about the lowest temperature at which microbes will grow and thrive. Optimal temperature is 120 degrees F, with 130-140 degrees F being the point for killing most pathogens. Aerobic microorganisms produce heat as they eat, and high-nitrogen materials provide ample food to encourage heat production in a small space.
What to avoid
Unless you are able to strictly monitor internal compost temperatures or include additives, you should avoid adding meat and dairy to your compost pile. Also avoid adding any animal waste, such as chicken or dog feces. Composting animal requires heat to kill any harmful microbes, so it’s best to avoid it.
Yard waste and grass clippings are a great source of nitrogen for your compost, but avoid using clippings from weeds or grasses that have gone to seed, as your compost will be happy to spread those seeds all over your garden. Although if you’re using an enclosed composter that encourages higher heat, you may not have too much of an issue with weeds gone to seed.
Traditionally, compost areas are designed as open spaces or piles and are left for long periods of time to break down the organic matter. There are several great alternatives that can give you fantastic compost without sacrificing valuable space.
Tumblers are a great way to compost while saving space. Tumblers perform the important job of encouraging aeration by rotating a closed container. Often, tumblers rotate via a hand crank on an axis, but there are other models, such as sealed and aerated drums. By being enclosed, they also discourage pets, rodents, and other pests from rummaging through your compost pile. Some models can get pricey, so there is always the option of constructing one yourself.
Composting by employing the workforce of worms, also known as vermicomposting, can be a valuable space-saving tool to create compost right in your own kitchen. Provided you keep your worms happy – small, worm-sized green, nitrogen-rich matter and brown, carbon-rich matter.
What makes this particularly great for small spaces is that it is easy to scale down based on your particular space requirements. Vermicomposting utilizes redworms (Eisenia foetida), also known as red wigglers. You could buy a vermicomposting kit to get started, but the intrepid composter on a budget could make his or her own worm bin.
Bokashi is the Japanese word meaning ‘fermented organic matter’ and works as a slow-acting fertilizer; bokashi can be used as a partner strategy to traditional composting, making your organic waste break down faster. While bokashi is sometimes referred to as a type of compost, it actually is a created through an aerobic fermentation process, and ‘activates’ when mixed with compost or soil. When done correctly, the result is generally free of foul odors.
Bokashi is appropriate for small or large scale; to get started you need a bucket with a lid, a spigot at the bottom to remove leachate, and bokashi mix, which is essentially wheat bran inoculated with microbes. Bokashi mix is available for purchase, but you can make your own.
Don’t let space limit your ability to compost. Small scale composting requires a smaller footprint than large open compost bins, and can provide useable compost in a much shorter time. There are indoor and outdoor options that can provide you with black gold for your garden while reducing landfill waste and the need for chemical fertilizers. All that is left is for you to decide what type of composting system will work best for your small space.