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Until recently, composting was used mainly for what it could provide: a healthy soil amendment. Now, composting has become a popular way to recycle food and paper waste in an effort to keep unnecessary items out of landfills.
So, composting methods can be broken down into two categories:
Product-oriented composting is focused on producing high-quality compost in order to improve the soil. These compost piles are generally larger, outdoors, and may require bringing in green or brown ingredients to make piles consistently. Success is measured by how nutritious the matured product is, and how much it improves specific soil properties.
Process-oriented composting is focused on keeping waste out of the landfill, and recycling as much organic material as possible. These piles can be any size, but they are generally smaller, slower, and may produce a sub-par product.
Success is measured by how many recyclable products are able to be decomposed and incorporated back into the soil, not the nutritional value.
Let’s look at examples for both types of composting and layout the needed size, location, maintenance, and construction (or cost).
Simple Compost Pile
A simple compost pile consists of a large pile of organic material that is exposed to the elements. These piles are generally product-oriented.
In order for a pile in this environment to decompose, it should be a 4’ cubic mound of alternating brown and green ingredients. Smaller piles will break down, but it can take longer for the bacteria to reach the temperatures necessary to break down tough, fibrous material (source).
For a process-oriented composter, it’s better to pile all of your yard waste into one pile rather than one pile of twigs, a separate pile of grass clippings, etc.
This will at least provide green and brown ingredients and can help you recycle yard waste that breaks down within the year. You can add kitchen scraps to this pile to keep them out of your garbage can.
A simple compost pile can be almost anywhere as long as it’s outside. These piles have no containment besides maybe a large square bin, and they require space to “breathe” to prevent foul odors.
You can put a compost pile anywhere, but your neighbors will probably prefer you keep it in your backyard. It’s important to put your pile somewhere where you can add to it, turn it, water it, and use it easily.
If you live in a cooler, damp environment, consider placing your compost pile on a pallet or a base of thick twigs to encourage airflow. If you live in a warmer, drier environment, consider placing your pile in part shade with a tarp or lid to help conserve moisture.
A simple compost pile should be turned every 3-6 days. If the compost pile seems moist, dark, and warm when you turn it, it’s working.
For more accurate timing, buy a compost thermometer (link to Amazon). It should rise quickly after you turn it and hit about 160 °, then drop slowly for a few days until it hits 130°. Turn it, and repeat. In drier climates, you may have to wet down the pile when you turn it.
If you want to build a compost pile at one time and have it mature in a few months, then you will want to avoid adding too much during the process. If you do want to add kitchen scraps while it’s composting, wait until you turn it and mix the new greens into the center.
When the compost remains at a fairly steady temperature after turning, it’s ready to mature. Allow the compost to sit for a few weeks or months until the compost smells earthy and crumbles in your hand. There should be no discernable plant matter and no foul odors. After this curing, or maturing, process, your compost is ready to use.
Most simple compost piles are just piles on the ground. Follow the rule of 4” of brown and 2” of green when you layer your ingredients, and it should decompose nicely.
If you plan on building multiple piles, or would like to keep the area more tidy and clean, you can build 3-sided bins and add gates (or not) to keep your piles contained. Build the bins out of non-treated lumber with large spaces between slats for air flow.
A tumbler is a great option for small-scale product-oriented composters and serious process-oriented composters. A tumbler will need consistent additions and turning to prevent foul odors and mold, so they work best for gardeners who like to add a little every few days and use the finished product in a raised bed or small-scale garden.
A compost tumbler is exactly what it sounds like; a rotating container. The advantage of tumblers is that you can use them if you have no yard space. They are completely enclosed, so you can put them on a patio, balcony, or indoors.
Small tumblers average about 20 gallons, while large tumblers can be 80+ gallons, which is 1/6th of a 4’ cubic pile. Many tumblers are dual-sided, so you can add new material to one side while the other side is maturing.
Most tumblers are easy to turn, move, and clean. Many are raised to hip-height, so they are easy to access and harder for critters to get into.
Compost tumblers can be indoors or outdoors, but they do have holes for aeration, and these holes can also release liquid. It’s best to place tumblers in the sun or part shade where they can get some airflow.
Large tumblers can get heavy. An 80-gallon tumbler could produce 20 gallons of compost, or about 3 cubic feet, per cycle. The finished compost will weigh about 80 lbs, and the tumbler itself weighs 40 lbs. Make sure your platform will be able to support this amount of weight.
Maintenance on a tumbler is simple: when you have food scraps, throw them in. Then, turn. Make sure you keep the C:N ratio within range, and the bacteria should do the rest.
Tumblers retain moisture much easier than open, simple compost piles. Adding moist greens on a consistent basis should be enough to maintain active decomposition unless your tumbler is exposed to excessive heat or wind. If you open the door and it feels dry, sprinkle some water inside.
Tumblers range from $20 for small units to over $250 for large units. For larger-scale composters, 80-gallon tumblers will cost between $150 and $250 and should last a lifetime if it’s maintained.
If your goal is to produce compost on a consistent basis, you should weigh the cost of a tumbler against the cost of bagged compost.
An 80-gallon compost tumbler will produce about 20 gallons of finished compost, which is the equivalent of one 3 cubic foot bag of compost. These bags will typically cost about $10 at a hardware store. You would have to produce 15-25 rounds of compost for the tumbler to pay for itself.
A 3 cu’ bag of compost will cover a 6’x6’ area 1” deep.
Tumblers take longer to turn less material into a finished product than if you used a simple compost pile. However, if you have a small growing area, small storage area, or are simply interested in using compost as a way to recycle, tumblers are a great option.
Vermicomposting is the most popular method of composting, because it is easy to scale up or down and the finished product is a high-quality, potent fertilizer. For this method, containers are filled with shredded paper, and then worms are released into the container and fed a steady diet of kitchen scraps.
This method is best for product-oriented composters. Vermicomposting requires more maintenance than all other composting methods, and it produces an extremely potent fertilizer (not soil conditioner). There are much easier ways to recycle kitchen scraps and shredded paper if your main focus is reducing waste.
Vermicomposting produces two usable products: worm castings and compost tea. Both are produced in small volumes, but with extremely high nitrogen content. These products can cause nitrogen burn if they are used improperly. They should not be spread over a large area like other compost products.
If a worm bin is maintained properly, worms will multiply quickly and they will need room to grow. Most homemade worm bins are built out of old plastic totes and containers. Worm bins are easy to bring inside, and as long as you maintain them properly, they shouldn’t smell. This makes them an ideal option for gardeners with limited space.
Worms need dark, cool temperatures, so it’s best to put a worm bin in a protected, outdoor location, or inside a garage or basement. Worms need to stay moist, and they will need to be fed every few days, so the worm bin should be easily accessible.
Large food scraps like melon rinds and banana peels will take longer to break down unless you chop them up. Each time you feed the worms, dig down into the bedding a few inches, and bury the food. Make sure the bedding feels moist, but not wet. If it’s dry, mist the box with a spray bottle.
Worms can be picky about what they eat, so the ingredients are more limited for this composting method. Acidic, spicy, or citrusy foods can damage the worms, so it’s best to stick to mild fruit and vegetable scraps.
There are many options for constructing or buying a worm bin. Almost all will have the same basic design; a box that you fill with moist bedding, small holes for aeration, a lid to keep the bin dark, and a spigot to drain the liquid that collects on the bottom.
Once your worm bin is set up, buy the appropriate amount of red wigglers for the volume of your bin. Do not use worms you find in the garden in your worm bin; they are not suited for cramped spaces, and they will either die or take a long time to break down food.
Vermicomposting produces worm castings. These castings settle to the bottom of the bin, so most worm bins will have a way to remove the bottom to collect them.
This method of composting is almost entirely for process-oriented composters. The main reason for this is that the finished product is basically worthless for most gardeners.
Bokashi composting intentionally encourages anaerobic bacteria to break down a wide variety of food waste.
- The major benefit of this method is that you can compost meat, bread, cooked vegetables, and other items that are off-limits in typical compost piles.
- The major drawback of Bokashi composting is that it does not allow for breaking down traditional brown (carbon) ingredients, so you would have to find another method for recycling paper and cardboard.
The end result of bokashi composting is a fermented brew of sludgy kitchen waste. This can be safely disposed of in most soils, but it can actually harm garden beds. If you use the Bokashi composting method, pour the “compost” around established plants, or spread it out over a large area.
Most compost bins for the bokashi method are the size of a 5-gallon bucket. In fact, you can purchase the inoculant (link to Amazon), which is the bacteria, and make your own bokashi bin out of any bucket with an airtight seal. These buckets can be stored almost anywhere because they are fairly small, and they are completely sealed, so they don’t release foul odors.
Bokashi buckets are easy to maintain and store. They’re small, and since you only add kitchen scraps, not lawn waste, you can keep it in the kitchen under a counter.
Full buckets can be heavy, and as the mixture ferments, you will need to drain off the liquid, so keep it in a place where you can access the spigot easily.
Food scraps will be smashed inside the bucket with thin layers of inoculant. The bokashi process is anaerobic, so it’s important to remove as many air pockets as possible when adding ingredients.
Every few days, drain off the liquid from the bottom and use it as a fertilizer. This liquid can be acidic, so use it around cucumbers, beans, hydrangeas, blueberries, evergreens, and other acid-loving plants.
Once the mixture has fermented, you can decide how to use it. The food scraps won’t change in appearance; you’re essentially pickling your kitchen waste. However, you can add this mixture into a simple compost pile and bacteria will be able to break it down very quickly. The major benefit to this is that you can add meat, dairy, and bread to your compost pile as long as you ferment them first.
You can also mix the finished “compost” into the soil after it has fermented. It won’t add much nutritional value, and it may lower pH. However, it is a simple way to recycle kitchen scraps that would otherwise be thrown in a landfill.
Bokashi bins are simple; find a bucket with a lid and buy inoculant. There is no way to build a bokashi compost bin out of traditional products like wood. Your container must be airtight with a lid that is fairly easy to remove, and a spigot at the bottom.
If you don’t want to purchase a bokashi bin, you can drill a hole in a 5-gallon bucket and use silicone to add a spigot on the bottom.
You may want to purchase a plastic bucket opener to make daily maintenance and reuse of the bucket easier.
Looking for more information on composting? Check out Thriving Yard’s articles on in-ground composting and how to build an active compost pile. And if you really want to understand this process fully, be sure to read How Compost Is Made: The Definitive Guide