This information is for those of you who are already avid composters (you may not know some of these details) and also for you newbies who want to start out doing it RIGHT. But like I have said, composting can be as complicated or simple as you want to make it, so don’t get overwhelmed.
Before launching my composting services through Brown’s Greens, I did a lot of research into how composting is done well on a commercial scale. Though most of my readers will be backyard composters, the information I have now still applies to every compost pile, large or small. My biggest source of education has been a government document called 6 CCR 1007-2 Part 1 (https://www.colorado.gov/pacific/sites/default/files/Part-2.pdf), which is the Department of Health’s code of regulations that governs hazardous waste management. Compost is considered a hazardous waste here in Colorado, and thus falls under these regulations. The Dept of Health is the authority on how to do composting effectively. I also took a class on soil sciences, I have been composting in my backyard for 5 years, I’ve read books on it, and helped a lot of folks get started doing it. So here are the three largest concepts I have learned, and understanding them will help you have a killer compost pile.
A compost pile can vastly be improved if it has a well balanced mix of materials, which promotes the health of two key composters, Bacteria and Fungi. You need both of these guys to break down food scraps and yard waste properly, and when their food source is too heavy or lacking in one area you can create problems. So how do you get these guys balanced in your compost? The first step is to understand the ratios of materials going into your compost. You may have heard people talk about the “browns greens ratio”. This refers to two types of raw materials that you put into a compost pile. “Green” materials are new, recently died materials that still have some green or other life colors in them (fresh grass clippings, veggie and fruit scraps, manure, etc). “Brown” materials are older, woodier, long dead materials (wood chips, straw, twigs, etc). The easy ratio to follow is 1 to 1, 50% green compost and 50% brown compost. Some people say you need more green than brown, some say you need more brown than green, but we and many other composters use half and half without issue. Watching this ratio can help keep Bacteria and Fungi happy. There is another ratio that you need to keep in mind and that’s the carbon to nitrogen ratio, or the C:N ratio. This ratio is often confused with the browns greens ratio because there are links between them, but they have slightly different focuses. All organic materials have certain levels of carbon and nitrogen in them and both play a key role in composting. Generally, “brown” compost materials have a high C:N ratio, usually 30:1 or more, meaning there are 30 parts carbon to every 1 part nitrogen in that specific material. “Green” compost has a low C:N ratio which could be as low as 10:1. Most experts say the ideal ratio is about 20:1 C:N. People tend to use the terms in these ratios interchangeably, which is where the confusion begins because they will use the word nitrogen in place of green, and carbon in place of brown. These terms should not be used interchangeably because a good compost pile with a browns:greens ratio of 1:1 does NOT have a C:N of 1:1. Or vice versa, a pile with 20:1 C:N does NOT have 20 parts brown material and 1 part green. One ratio looks at the overall mix of types of materials (browns:greens) and one ratio looks at the chemical makeup in each specific material and/or the entire mix (C:N). This can seem intimidating to keep track of when maintaining your pile, but the take-away concept is simple. Don’t agonize over doing gobs of math to get the C:N ratio of an entire pile right, because generally, mixing 50% browns with 50% greens will get you there.
Now that you understand the ratios of compost materials, you can understand how they affect bacteria and fungi breaking them down. Both of these microbes need to be fed well and they also need to be well balanced in the compost. Bacteria like to break down materials that are high in nitrogen, generally “green” compost. When you think food for the bacteria, think light, fluffy, green organic matter. Fungi, however, like carbon rich waste, generally “brown” compost. For Fungi food, think denser, woodier, harder stuff. Keeping your browns greens ratio correct will keep these microbes balanced in the compost.
TURN IT, BUT NOT TOO MUCH:
It is very important to turn your compost pile occasionally so that oxygen is introduced into the decomposition process. But if you turn it too much, you are slowing down the composting process and potentially allowing some detrimental microbes/weed seeds to survive that you don’t want to survive. The Department of Health advises to allow the center of your compost pile to reach 131 degrees Fahrenheit or hotter before turning. They advise to let it remain at this temperature for 15 days, and they require the pile to be flipped a total of 5 times. So the ideal formula would be to bring the pile to 131 degrees, let it sit for 3 days, then flip it, and repeat the process 5 times. Once you’ve done this, you have finished, safe, ready to use compost. This can take a while, in Colorado usually close to a year. And of course, remember to moisten the compost when you turn it. You don’t ever want it to be soupy or sludgy, but moist is good.
HAVE MULTIPLE PILES:
A mistake all of us backyard composters make is we try to do everything in one pile. You can do this, but it takes waaaaaay longer to produce usable compost. I recommend that you maintain at least two piles at a time. One pile for your fresh food scraps and yard waste, one pile for your compost that is already in process. When you have a pile that’s decomposing and generating heat as the microbes do their work, every new load of fresh plant matter is more work for the microbes to incorporate and it slows the process down. Once I started separating out my piles by age, I noticed a HUGE difference in both speed and compost quality.
I hope this article helps you get a better grasp on what makes for a good compost pile. As long as you keep an eye on your browns:greens ratio and you are intentional about your pile maintenance, you’ll do great. Happy composting!