Hot compost, worm compost, compost tea… oh my! Welcome to your crash-course introduction on all things compost. If you are new to composting and feel intimidated, I get it. There is a lot of information out there, and so many different ways to compost! However, the core concepts and science behind all types of compost are dang near the same, so let’s break it down to the basics.
After reading this article, you’ll have a better understanding of what compost is, how it works, and why it is important. We’ll go over what types of materials can be composted, those that should be avoided, and the six most common and easy ways to compost at home. Then you can get busy sustainably recycling food waste and creating your own amazing free fertilizer – right in your backyard!
Ready to dig in? Good. Me too.
What is Compost
In the most simple terms, compost is decomposed organic matter. Composting is the process of adding a balanced combination of biodegradable materials together, such as leaves, straw, dry grass clippings, kitchen scraps, and garden waste. With the help of decomposers (microorganisms, worms, insects, fungi, etc) and the right conditions, the raw materials break down into one homogenous nutrient-rich, soil-like material – finished compost.
Finished compost is often referred to as “black gold”, and rightly so. It is truly phenomenal stuff! Compost is a rich, balanced, natural organic fertilizer, and an invaluable resource for gardeners and organic farmers. Finished compost is often mixed into soil as an amendment. Or, it can be applied to the soil surface as mulch.
Compost provides the following benefits to soil:
- Compost increases the content of organic matter in soil, which in turn improves its texture, drainage, and fertility. These things all lead to happier, healthier, bigger, and more productive plants!
- Compost invigorates the soil food web by providing nutrients, moisture, and habitat for a large range of beneficial life forms. Have you heard of “organic living soil”? Essentially, it is the idea that soil is and should be treated as a living, breathing, dynamic ecosystem of its own. Healthy soil is full of beneficial bacteria, fungi, nematodes, insects, and more. That is what we try to foster here!
- By nourishing both the soil and plants, compost actually enhances plants’ immune systems! It also acts as a buffer to “cleanse” soil by naturally remediating any toxic substances within it. Therefore, plants grown with compost have a higher resistance to disease or stress, such as drought, pests, or weather extremes.
- When done correctly, compost provides all of these benefits with no risk of “burning” or shocking plants, which is a common concern with using synthetic fertilizers. Finally, as gardeners and farmers utilize organic compost more, they in turn reduce their dependence on less environmentally-friendly fertilizers.
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Why Composting is Important
Clearly, there are undeniable benefits to creating and using compost to support plant health in a home garden or farm setting. Yet even if you are not an avid gardener or don’t have the “need” for organic compost at home, I still urge you to practice composting at some level! There are so many benefits of composting – beyond the garden.
How is composting good for the environment?
According to the USDA, it is estimated that 30 to 40% of the food supply in America goes to waste each year. Let that sink in. That is INSANITY! We’re talking about 133 billion pounds of food. The United States has a reputation for being particularly wasteful, but food waste is occurring in astonishing numbers in every country across the globe.
While a portion of food waste can be attributed to food production errors, disease, or pest damage, experts report a 31% food loss in the consumer and retail sectors alone. Waste can occur when stores over-order or receive damaged food products. At home, it happens when people buy more food than they can (or make an effort to) consume.
Clearly this a huge issue; larger than we could ever compost our way out of. Everyone needs to work together to reduce the waste that occurs in the first place. But what happens once food does spoil or is otherwise disposed of….? We usually “throw it away”, right?
But where is “away” really?
Food waste leads to climate change
Food that is thrown in the trash ends up in landfills. Rotting materials in landfills pollute water resources via leachate. They also become anaerobic and create methane gas. Methane gas (the same stuff in cow farts, for the record) is a potent greenhouse gas, and happens to be 25 times more detrimental than carbon dioxide at trapping heat in our atmosphere. Needless to say, methane is a significant contributor to climate change. Landfills aside, the production and transportation involved with the food industry (including its waste) also generates a massive amount of carbon dioxide emissions.
“Globally, if food waste could be represented as its own country, it would be the third largest greenhouse gas emitter, behind China and the U.S.”Food and Agriculture Organization of the United Nations
Composting helps curb climate change & pollution
The act of composting diverts food waste otherwise destined for the landfill. Less food rotting in the landfill means less greenhouse gas emissions, along with a reduced risk of contaminating water resources. Composting is an awesome example of one of the best types of recycling: “upcycling”. Upcycling means transforming an unwanted waste product into something even better – like turning rotting food into “black gold”! Therefore, composting is highly encouraged on the home scale as well as a municipal or commercial level.
There are an increasing number of industrial or commercial compost facilities in operation, designed to take in huge volumes of waste and keep it out of the landfill. They turn it into compost, and usually sell it back to growers or the public. While this is awesome overall, there is less quality-control with the materials fed into commercial operations. They receive a lot of bulk green waste, including from parks, homes, or big farms. Some loads may be contaminated with herbicides, pesticides, treated wood, or other undesirable materials. If you have a garden, creating your own compost is the best way to go!
HOW TO COMPOST AT HOME
There are several ways to compost at home, including methods well-suited for nearly every living situation. Enclosed compost tumblers or worm bins are perfect for small gardens or urban conditions. Big compost bins or piles may be more fitting for larger properties to small farms. Some methods are more active and involved, while others are quite hands-off. And contrary to popular belief, compost piles do not stink! Or at least they shouldn’t, as long as they’re properly maintained.
Let’s briefly go over six different ways to compost at home. Keep in mind that I plan to write more in-depth articles on each method in the near future as well!
Composting Starts in the Kitchen: Gathering the Goods
No matter what compost method you choose to implement at home, nearly every one of them starts in the kitchen. As you are cooking, preparing meals for the week, or cleaning out the fridge, food scraps tend to pile up. However, it is inconvenient to tote your kitchen scraps outside to the compost pile every time they appear!
The best solution is to collect compostable food waste in a small kitchen compost bin, and then take it out to the main pile once or twice per week. That frequency is usually sufficient to prevent excessive mold or odors in your kitchen compost bin.
We currently use this awesome little stainless steel kitchen crock. Between the tight-fitting lid and the built-in carbon filter, it effectively keeps odors in – and fruit flies out! We store ours under the kitchen sink, though it is attractive enough to keep on the countertop as well. We’ve also used this even more stylish ceramic compost crock in the past. It too has a carbon filter in the lid, and we happily used it for years! Until I dropped the lid on the concrete patio, that is… Bummer.
1) Passive Compost Pile
A passive compost pile is when materials are piled up and then allowed to slowly decompose over time. It could be a literal free-standing pile in the corner of the garden, but is most often contained within a compost bin of some sort.
Some compost bins are as simple as a single wood or wire-framed stall, typically enclosed on three sides and open on the front for access. Other compost bins have two or three “bays”, designed to enable easy turning and rotating of the piles. We currently have a single-compartment passive pile, but want to build a two or three bay system soon! Once we figure out where we have space for one, that is…
This style of composting is referred to as “passive” because we are simply letting nature take its course. Passive piles are perfect for beginners, or folks who don’t have time to tend to other types of compost systems. There is minimal intervention, aside from perhaps turning the pile from time to time. It is usually a fairly slow process, and the pile stays cool. This is in contrast to a hot compost pile, described below.
2) Compost Tumblers
A compost tumbler is another form of passive composting, but usually on a slightly smaller scale. While you may not be able to cram as much material into a tumbler as you would a large open passive pile, compost tumbler bins have some serious perks!
The first huge benefit of tumblers is how easy they make it to “turn your pile”. Occasionally turning a compost pile introduces air, which promotes decomposition, balances moisture, and also reduces odors. As the name suggests, compost tumbler bins are made to… errhm, tumble! They’re designed to enable easy turning and churning of the material inside, without breaking your back. On the other hand, turning a large hot or passive pile can be quite the chore.
Another big perk of using a compost tumbler is the fact that they’re enclosed. While a well-maintained compost pile should not stink, it can happen. Keeping the compost contained also keeps unpleasant odors contained. Furthermore, an enclosed compost tumbler is far less attractive and accessible to rodents or other wildlife.
Tumbling compost bins come in many shapes, sizes, and styles. We love and use this two-compartment compost tumbler (pictured below). Having two compartments means you can actively “feed” or add material to one side of the bin, while allowing the second side to rest and thoroughly decompose. I also love the height of this tumbler. When it comes time to harvest finished compost, we simply stick a bucket or tub below it, turn the tumbler over it, slide open the door, and out it pours!
3) Worm Compost Bin
Ah, vermicomposting… That is the word for “composting with worms”, which happens to be one of my favorite ways to compost! Vermicomposting occurs when specialized compost worms are added to a compost pile. While you can add worms to a big passive pile, it is usually recommended to keep them in a confined container, aka the “worm bin”.
Like compost tumblers, worm bins are compact and tidy, perfect for smaller spaces or even to keep indoors. However, I don’t suggest worm bins for small gardens only! I think every home, garden, farm, or even schools and workplaces should have a worm bin. Worm bins do require weekly maintenance, but it is well worth the small effort.
Also similar to tumblers, worm bins or “worm farms” come in many sizes and styles. Some worm farms are fancy, with stackable tiers of trays and drainage systems. Others are made of a simple plastic tote or storage tub. Ever since my college days, we have always used a very basic homemade tote-style worm bin. They’re cheap and work great! We’ve even used one while living in an apartment.
For more details about how to make and maintain a simple worm bin like ours, see this article to learn all about it.
The Magic of Worm Castings
Compost worms can eat their body weight in food per day, which rapidly accelerates the breakdown of organic matter in a worm compost bin. Meaning, you get finished compost faster. Furthermore, the type of compost that worms produce is extra-special: worm castings. Worm castings or “vermicast” are simply more tasteful terms for worm poop.
Worm castings contain concentrated, highly-bioavailable nutrients from the materials they were originally fed. Even though the nutrients are more concentrated, worm castings are very mellow and cannot “burn” your plants like other animal manures easily can. This is because as materials pass through worms, they’re coated with a mucous membrane that turns the castings into the perfect little slow-release fertilizer granules.
When added to your garden soil, worm castings increase soil aeration, drainage, and water retention. Worm castings also increase nutrient uptake by plants, and aid in seed germination. Beneficial microbes are also introduced as raw material passes through a worms body, which helps support the precious soil food web.
4) Hot Compost Pile
When a compost pile has the right volume, composition, and moisture, it has the ability to heat up! We’re talking up to 160 degrees Fahrenheit, producing tangible heat and steam. A properly made and happily maintained hot compost pile creates the perfect environment for a bloom of beneficial microbial activity.
The microorganisms’ activity and bulk of the pile increases the temperature of the compost material and rapidly accelerates decomposition. Meaning, raw materials can break down into usable finished compost in just a matter of weeks (3 to 8 weeks, depending on conditions) rather than several months to a year like passive piles.
How to Create a Hot Compost Pile
In order for a compost pile to become hot:
- It must be at least 4 feet tall and 4 feet wide. Hot piles can be mounded up in the same types of bins or stalls as passive piles, or held together in a cylinder of wire fencing.
- The pile needs the right balance of carbon to nitrogen: about two-thirds “browns” (carbon) to one-third “greens” (nitrogen) by volume. Layering greens between browns is ideal. Read more about carbon and nitrogen sources in the “compostable materials” section below.
- Natural compost accelerants can be added to inoculate the pile with beneficial microbes.
- Finally, the pile should be moist but not soggy.
If you’re building a hot compost pile, monitor its temperature with a long probe compost thermometer. Once a hot pile hits the target temperature range of 130 to 160°F for several days, the activity and temperature will decrease. That’s a signal that it’s then time to turn the pile, to wake up the microbes and get cooking again. Ideally, folks have a second bin to completely turn the pile over in to. In our single-compartment bin, we simply toss it with a pitchfork to turn in place. See the video below!
If a hot compost pile temperature rises over 160°F, spread it out immediately to cool down! There is a small risk of a hot compost pile catching fire. However, that usually only happens in commercial settings with massive windrow piles.
Hot compost piles require more material, effort, and maintenance than other composting methods. However, this is a really awesome and efficient way to compost if you have a large volume of compostable material to work with. We don’t often have a ton of browns available in our garden, so building a hot pile is a special and fun project when we do! A more detailed article on this topic is coming soon.
5) Composting in Place
Some biodegradable materials can simply be left to decompose in place! This is one of the most hands-off ways to compost. For example, fallen leaves left to compost in place provide a layer of mulch that eventually breaks down into a rich humus, mimicking a natural forest floor. Aaron often collects our more woody garden waste (such as tree or shrub trimmings, a bit tough or large for the compost pile) and simply tosses them in a corner of the yard behind a large pineapple guava bush. There they lie to die!
We also practice “chop and drop” mulching by spreading out green or brown plant material over open areas of soil. This is an especially beneficial practice when using plants in the “dynamic accumulator” family, such as yarrow, borage, fava beans, comfrey, dandelion, miner’s lettuce, chickweed, or stinging nettle. Those “dynamic accumulators” readily take up nutrients and minerals from the soil, and then store them in highly bioavailable forms and concentrations in their leaves. This makes dynamic accumulators an excellent nutrient-rich addition to the soil surface, or to a compost pile.
Obviously, this passive way to compost is best applied to green waste and vegetation as opposed to kitchen scraps. Leaving food scraps out in the open will attract flies, rats, and other unwanted visitors to your garden. However, burying food waste may help with that!
6) Burying Food Waste
Another simple way to compost and divert your food waste from the landfill is to bury it in your yard or garden. It sounds a bit silly, but I have seen people do it! Can’t you just picture someone running around their yard digging little holes and filling them with food scraps after every dinner prep? One slightly less neurotic way to bury food waste is to create a long trench between rows of vegetable crops. Then, fill the trench with a thin layer of food scraps and simply backfill it.
Theoretically, the food will decompose in place – feeding worms, other insects, soil, and the soil food web in the process. This method can only handle a limited quantity of food waste, and could potentially tempt wildlife to dig in the chosen burial site.
Municipal or Commercial Compost
One final way to compost is to rely on your city to do it for you! If you’re unable or uninterested in maintaining a compost system at home, check to see what local services are available to you instead. Can you recycle your garden and food waste through your curbside trash pickup, or is there at least a local drop-off facility around?
In our town, we have three big bins provided by the local sanitation district. One is for trash, one for recycling, and the third is our “green waste” bin. In the past, only materials like grass clippings, leaves, small tree branches, or other common yard waste was permitted in that bin. Then a few years ago, they began to accept kitchen scraps in the green waste bin too – destined for the local commercial compost facility. If your city does not offer this, contact them to voice your interest! Only certain types of food waste are allowed in the bin, those on the “yes” list – much like the one below.
Let’s talk about what materials can be composted, and what things you should avoid putting in your compost bin. Beyond a simple “good” and “bad” list, it is also important to know what group the materials belong to – in order to maintain a healthy and effective compost pile.
Compost Browns vs Greens
What do mushy banana peels, spent coffee grounds, limp lettuce, and nibbled-on apple cores have in common? Aside from being great additions to a compost pile, they’re all considered sources of nitrogen – or members of the “greens” group. More often than not, they have a high moisture content. On the other hand, dry materials such as straw, dried leaves, fine wood chips, or even paper are all sources of carbon in a compost pile – the “browns”.
It can get a tad confusing since not every nitrogen source will actually be green in color. Take coffee grounds for example. Or poop. Furthermore, some greens can eventually turn into browns, such as fresh grass clippings that are allowed to dry out before being composted. But in general, all compostable materials can be broken down into those two main categories.
What Can You Put In A Compost Bin? The YES List
In a nutshell, far more materials can be composted at home than cannot. Meaning, if it is not on the “no no” list, it is likely fair game!
With time and experience you’ll learn what materials best suit your personal compost system. For instance, woody branches may be too large or take too long to decompose in a tumbler system – even though they’re on the “yes” list. In general, smaller materials decompose faster. Therefore, you may want to break or cut up large items like pumpkins to speed things up.
Please note that there are different rules for worm bins. Reference our Worm Bin 101 article for a complete list of what to feed your worm bin.
The nuances between the different ways to compost is part of why we use three or four different styles at home! That way, we can always find a suitable place for our waste.
|Good Greens: Example Nitrogen Sources for Compost Piles||Good Browns: Example Carbon Sources for Compost Piles|
|Fruit and vegetable scraps (citrus & onions in limited quantities)||Dry grass clippings (weed-free)|
|Yard trimmings and wet grass clippings||Dry leaves|
|Eggshells||Hay and straw|
|Nuts & nutshells||Peat moss|
|Leftover pasta, bread, or tortillas (limited)||Fine wood chips|
|Coffee grounds||Corn stalks|
|Loose-leaf tea||Dry Pine Needles|
|Leaves and houseplants||Paper towels and napkins (unbleached preferred)|
|Feathers||Dryer and vacuum lint|
|Hair & fur||Wood ash (in moderation)|
|Natural fertilizers, such as alfalfa meal, kelp meal or neem meal||Shredded newspaper, paper, and unwaxed cardboard|
Compost These Items With Caution (or in Limited Quantities)
- Citrus or other acidic items. Compost citrus in very small quantities. Rinds are better than whole fruit or juices. The high level of acidity in citrus can inhibit or kill beneficial bacteria in a compost pile. Avoid citrus in worm bins completely. Want to know how we upcycle citrus rinds? Check out this tutorial on how to make DIY citrus vinegar cleaning spray, or how to create dry lemon peel powder – a delicious and versatile seasoning! (Any type of citrus peel works for both options)
- Weeds or other plants that readily self-seed, such as borage. That is, unless they haven’t flowered and gone to seed yet, or if you remove the flowers/seeds first.
- Paper products or other items marketed as “biodegradable” or “compostable” such as paper plates, cups and straws. They may eventually decompose, but a lot of them take a very, very long time and may not be suitable for home compost systems.
- Coffee filters and tea bags. Unfortunately, many coffee filters and tea bags contain nylon or other synthetic fibers. This means they will not easily break down in your compost pile, nor do you want them there! Unless you’re certain they’re made from 100% natural fibers like cotton or hemp, avoid them. But definitely compost coffee grounds, and open up tea bags to compost the spent tea inside!
- Animal waste. If you are new to composting, do additional research before composting “acceptable” animal waste such as chicken, rabbit, goat, sheep, horse, or cow manure. Certain animal manures are more tricky to work with, including chicken manure. Chicken manure is extremely “hot” (high in nitrogen), and far too strong to apply to garden soil without properly composting it for several months first. It can harm or burn your plants. When we compost our chickens manure, we let it sit in the tumbler for several months and then add it to a hot compost pile with other materials to finish. The heat also helps to kill some pathogens and bacteria.
What Not to Compost: The NO List
The items on the “no” list are not suitable to compost for one or many reasons. They either cause noxious odors and unfavorable byproducts as they rot, attract pests, introduce risk of disease or toxins, are not biodegradable, or otherwise cause problems in a home compost pile.
Materials to avoid adding to the compost pile:
- Meat, fish, egg or poultry scraps
- Dairy products
- Metal or plastic (including sticky labels on store-bought fruits & veggies)
- Treated or painted wood (or treated wood sawdust)
- Fats, grease, lard or oils
- Processed foods
- Barbecue coal ash (usually contains chemical additives)
- Plants with obvious disease or pests, such as powdery mildew or aphids
- Human poop
- Dead animals or pet waste (never cat or dog poop, see animal waste exceptions in the “caution” area above)
Compost Carbon to Nitrogen Ratio: It’s All About Balance
Now that you know what items can be composted at home (or not), let’s talk about best practices of how to actually add those things to a compost pile.
One of the biggest mistakes compost newbies make is adding materials in the wrong quantities. In general, a compost pile will be most healthy and happy with significantly more carbon than nitrogen. Meaning, you cannot simply throw heaps of wet food waste into a compost pile week after week without adding a good amount of browns to help compensate and maintain balance.
The ideal compost pile should have a carbon-to-nitrogen ratio (otherwise known as C:N) of about 30 parts carbon to 1 part nitrogen. This gets confusing since it doesn’t equate to 30 times more browns than greens. See, every material has its own C:N makeup that plays into that overall ratio. However, it does mean much more dried browns than greens!
To keep it simple, aim for a goal of about two-thirds browns to one-third greens by volume.
This doesn’t need to be an exact science, but trust me… you’ll want to maintain a fairly well-balanced pile. Why? When a compost pile has too much wet green material, it will start to stink like rotting trash! It is gross, and will also attract more pests. Too much nitrogen and moisture (combined with insufficient carbon) quickly lead to anaerobic conditions, or “without air”. The beneficial bacteria and critters that aid in good decomposition like aerobic conditions instead. A good fluffing and addition of browns can help turn a nasty pile into a nice pile.
A well-balanced, modestly damp, and routinely turned compost pile will only mildly smell – like natural earthy material!
Layer & Bury Your Food Waste
Another common composting mistake is not burying the food waste or nitrogen material. Covering greens is important for so many reasons: it prevents odors, flies, wildlife or pests, and also helps everything efficiently decompose.
So, when you go to dump your kitchen crock, dig a hole in the compost pile, add the food waste, and then cover it back up. Or, give the tumbler a spin to mix everything up. Depending on the current composition of your compost, you might not need to add browns every single time you add green material. But plan to do so routinely, and definitely when you add a lot of green material at once. Tip: If you don’t have many browns around your property, go rake up some leaves at the local park! Been there, done that.
Speaking of a lot of material at once… let’s talk about building up a big compost pile! If you happen to have a surplus of green and brown material at one time, it is best to add them to a compost pile in “lasagna layers”. For example, when we clear out the garden beds at the end of the season. First we lay down a thick layer of leaves or straw, then a thinner layer of green plant material on top, another layer of browns, more greens, and so on.
Watering a Compost Pile
Just as with carbon and nitrogen, you want to achieve a nice balance of moisture in your compost. Not too dry, but not too soggy. Damp is good. An overly dry and airy pile will decompose very slowly. On the other hand, compost that is too wet can easily become stinky and anaerobic.
Because it doesn’t rain most of the year here, we sometimes need to water our large passive or hot piles to keep the microbes happy. Yet we rarely find the need to add additional water to the enclosed tumbler or worm bin. The moisture from the wet green matter usually keeps everything damp enough.
Harvesting Finished Compost
Once the majority of the raw materials have broken down, it is time to harvest and use your finished compost! The exact process of harvesting compost varies depending on the kind of system used. Most often, gardeners sift their finished compost to remove any remaining large pieces, leaving them behind to break down further. We made a DIY compost screen by attaching mesh wire material to a wood frame. It can sit over a small tote when sifting worm castings, or over the wheel barrow to sift material from the big piles. (See this article to learn how to harvest worm castings from a worm bin)
Ways to Use Compost in the Garden
There are many wonderful ways to use compost in the garden. Finished compost can be mixed in to enrich existing soil, or added to a raised garden bed or container when it is first filled with soil. Read all about how we fill our raised garden beds with the “perfect” organic living soil here.
Compost can also be applied to the surface of soil as a natural fertilizer top-dressing, doubling up as mulch. Compost is our preferred mulch material in our raised beds. We also like to add a healthy dose of compost to the hole when planting new trees. Some of our most spoiled house plants also get compost and/or worm castings mixed into their pots.
Last but not least, my absolute favorite way to use compost is to make actively aerated compost tea, also known as AACT. Actively aerated compost tea is made by steeping compost in water (like a giant tea bag) and also introducing air – usually through an air pump and bubbler of some sort. The result is a biologically active brew full of nutrients and beneficial microbes. Water your plants with it, and watch them flourish! It is like “black gold”, but on steroids. We use AACT more than any other fertilizer, and most often with worm castings. Learn more about how to make actively aerated compost tea here!
And that concludes your crash-course introduction to compost!
What do you think? Are you still here? I hope your brain didn’t decompose on me… Are you feeling excited and empowered to start composting at home now too? I sure hope so. As always, please feel free to ask questions, share your insights, and spread the compost love by sharing this article! Because after all, compost is the shit. If you’re on Instagram, tag #homesteadandchill or @deanncat3 in your home compost adventures.
Finally, if you’re growing food at home and need inspiration on how to use more of what you grow be sure to check out our “Preserve Your Harvest” articles. There are dozens of tutorials and recipes on how to dehydrate, ferment, pickle, or freeze your excess homegrown goodies – so they don’t go to waste!