The complete guide to composting
Getting started, benefits, and how to manage at scale
With the demand for organic fertilizer ever rising, compositing will continue to grow in popularity and profitability. In fact, the United States environmental protection agency EPA, reports that the country recovered approximately 25 million tons of municipal solid waste through and more than 69 million via recycling in 2018.
To help you start and manage a successful small- or large-scale compost business, or how to best compost on your small farm, we have shared some insights below.
What is composting?
Composting is a natural aerobic process by which effective microorganisms convert organic materials into a more stable and usable form referred to as compost. Therefore, compost is a mass of fully decomposed organic matter (from material such as food scraps, animal manure, or plant waste products). The effective microorganisms that break down organic matter during composting are usually the aerobic decomposers including naturally occurring bacteria and fungi. Composting differs from anaerobic decomposition in that the former is an oxygen-dependent process resulting in carbon dioxide, water, energy, and black humus while the latter is an oxygen-nondependent process that produces methane, water, and carbon dioxide. A typical anaerobic decomposition occurs in landfills producing methane which causes the catastrophic greenhouse effect and global warming. Composting is done on small scale (home composting) or on large scale (industrial composting). Mature compost is usually added to farms as a soil conditioner and an organic fertilizer.
How does composting work
As earlier stated, composting is a controlled aerobic decomposition (requires oxygen) carried out by naturally occurring microorganisms. This process requires an optimum level of carbon-to-nitrogen ratio, oxygen, moisture, and temperature.
A balance between carbon and nitrogen is crucial for the decomposers to grow and multiply. Green organic material contains nitrogen while the brown organic matter has carbon. So, you should balance the green and brown materials to maintain an optimum carbon: nitrogen ratio. Air is also an equally important parameter in composting because the decomposers use it for respiration. Insufficient oxygen leads to anaerobic fermentation which might generate an unpleasant smell. You can ensure your compost is aerated by turning it regularly.
Similarly, correct moisture levels enable the microorganisms to break down organic faster. On the contrary, the excessive water content in the compost can slow down the process. You can regulate the moisture in your compost by balancing fresh and dry materials. Besides, you can water the compost if it becomes too dry.
Lastly, the temperature is an indicator of microbial activity. High temperature indicates that decomposition is happening at a fast rate whereas low temperature denotes a decrease in microbial activity.
Benefits of composting
If used correctly, compost can save you money by lowering soil maintenance costs, providing clean manure, and enhancing sustainability. Here are some of the benefits of composting:
A mature compost contains essential nutrients in smaller quantities compared to synthetic fertilizers. So, the compost can be applied in large quantities to serve as an organic fertilizer which can act as a substitute for chemical fertilizers.
Composting helps minimize the greenhouse effect, global warming, and climate change. Unlike anaerobic digestion, a well-aerated and watered compost emits reduced amounts of carbon dioxide, methane, and other greenhouse gases which are known to promote global warming.
Compost improves the soil’s nutrient retention ability, balances pH and soil density as well. These critical aspects of the soil boost healthy plant growth.
Composting increases soil microorganisms which capture and store atmospheric carbon dioxide in a more stable form (carbon sequestration).
Adding cured compost to your farm increases water infiltration and binds the soil together thus reducing soil erosion.
Composting produces heat energy which can be tapped and used to heat homes or warehouses.
Composting is an awesome waste management technique. When you compost, you reduce the amount of waste dumped in landfills and recycle organic waste into soil conditioners.
Disadvantages of composting
Although composting has a wide range of benefits, it is not short of limitations. Below are some of the disadvantages:
If you don’t provide enough air and moisture, decomposition will occur slowly and anaerobically. This may lead to low-quality compost or the production of an irritating smell.
Composting generates certain amounts of greenhouse gases such as methane and nitrous oxide.
Controlling unpleasant smells can be costly especially when composting is done near residential areas.
Organic compost might not contain enough macronutrients needed by plants. Therefore, compost has to be applied in large amounts or be supplemented with inorganic fertilizers.
People in the urban setting don’t separate organic from inorganic trash making composting such waste difficult.
Which materials can be composted?
Most organic materials are suitable for composting. These include:
Plant and tree leaves
Small plant branches
Wood chips, shavings, or sawdust
Coffee grounds and tea
Paper tea bags
Black and white newspaper
Other food and vegetable scraps
What to avoid putting into your compost
Manure from pigs, cats, dogs, humans, and other non-herbivores might contain pathogenic microorganisms and shouldn’t be added to the compost.
Petroleum products such as grease, engine oils, or fats.
Painted wood, leaves, or shavings
Meat, bones, and dairy products
Colored newspapers and magazines
How to start composting
Although composting is a great way to keep your garden soil healthy and lively, many gardeners and small-scale farmers don’t compost their organic waste. Some farmers believe that compost produces unpleasant smell others are impatient to wait for it to mature but a great number do not know where to start. Below are the simple steps to start your home composting
1. Separate food and vegetable scraps from other wastes
First, separate the biodegradable waste from the non-biodegradable materials. For a start, you can use set aside easily degradable materials such as fruit and vegetable waste. You can also use select coffee grounds, eggshells, and tea bags. However, you should avoid meat and dairy products since such products attract rodents into the compound.
2. Keep the food scraps
Properly store the food scraps you have set aside as you assemble enough waste for composting.
3. Choose the location for your compost
At this stage, you choose an appropriate site for composting depending on the amount of space available in your residence. Composting at home can be done in the backyard. However, you can use compost bins available in the market for those without backyards.
4. Prepare the compost mix
The “greens” and “browns” we mentioned earlier on apply at this stage. "Greens" refer to green organic matter such as fruit and vegetable peels, coffee grounds, or, grass clippings. Greens are rich in nitrogen which is an essential nutrient for microbial growth and reproduction. On the other hand, "Browns" contains much-needed carbon and include newspapers, egg cartons, pine needles, and dried leaves. The role of browns in compost is to provide food and energy to the bacteria and fungi responsible for decomposition. Ensure you crush eggshells and shred papers before adding them to the compost pile.
Generally, green materials are wet whereas brown materials are dry. When piling, you should ensure the browns are at the bottom and the wet greens on the top. This technique of layering ensures the compost is wet and aerated enabling decomposers to break down organic materials effectively.
5. Wait for decomposition to occur
After you have prepared your compost mix, you should wait for it to mature. The time taken for a compost mature will depend on location. In warmer regions, compost can take as little as two months to get cured. On the contrary, compost in cold regions can take over five months to mature. Note that you should turn the compost regularly, let’s say once every week. Turning keeps the compost sufficiently aerated and ensures that it is evenly decomposed.
6. Harvest and use
As the compost matures, it will turn from a raw greenish brown color to dark brown humus with a likable earthly aroma. It will also cool down because decomposition has ended. If your compost meets these checks, it is ready to be used.
Types of Large-scale composting
In vessel composting
In-vessel biodegradation can process huge quantities of waste while taking up less space than the windrow technique, and it can handle almost any kind of organic waste (e.g., meat, animal manure, biosolids, food scraps). Organic materials are fed into a drum, silo, concrete-lined trench, or similar piece of equipment using this method. This allows for precise control of environmental parameters such as temperature, humidity, and airflow. To ensure that the material is aerated, it is mechanically turned or mixed. The size and capacity of the vessel can vary.
This method yields compost in a matter of weeks. It will be a few weeks or months before it is ready to use because the microbial activity must be balanced and the pile must cool.
Institutions that plan to compost small quantities of food scraps can do so on-site. Composting can considerably reduce the amount of food that is wasted. Yard waste and small amounts of food scraps can also be composted on-site. Animal waste and large amounts of organic waste are not suitable for onsite composting.
Aerated Static Pile Composting
Compost is produced relatively quickly by aerated static pile composting (within three to six months). It works well for larger quantity generators of yard trimmings and compostable municipal solid waste (e.g., food scraps, paper products), such as local governments, landscapers, or farms. However, this method is ineffective for composting animal byproducts or grease from food processing industries.
Organic waste is mixed in a large pile in aerated static pile composting. Layers of loosely piled bulking agents (e.g., wood chips, shredded newspaper) are added to the pile to allow air to pass from the bottom to the top. The piles can also be placed on top of a pipe system that supplies or draw air into the pile. A timer or thermistors could activate air blowers.
Aerated (Turned) Windrow Composting
Aerated or turned windrow composting is appropriate for large volumes, such as those generated by entire neighborhoods and collected by local governments, as well as high-volume food-processing operations (e.g., restaurants, cafeterias, and packing plants). It will produce a significant amount of compost, which may necessitate assistance in marketing the end product. Municipalities may wish to make compost available to residents at a low or no cost.
This method of composting entails separating the organic waste into rows of long piles known as "windrows" and aerating them on a regular basis by turning the piles manually or mechanically. The ideal pile height is four to eight feet, with a width of 14 to sixteen feet. This size pile generates enough heat to keep temperatures stable. It's indeed small enough to allow oxygen to circulate to the core of the pile.
This technique can compost a wide range of wastes, including yard trimmings, grease, liquids, and animal byproducts (such as fish and poultry waste).
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To make compost, red worms in bins consume food scraps, yard trimmings, and other organic matter. Worms decompose this material into high-quality compost known as castings. Worm bins are simple to build and can also be purchased. A pound of mature worms (roughly 800-1,000 worms) can consume up to half a pound of organic matter per day. The bins can be customized to accommodate the volume of kitchen waste that will be converted into castings.
Producing usable castings typically takes 3 to 4 months. Castings can be used to make potting soil. Worm tea, another byproduct of vermicomposting, is often used as a high-quality liquid fertilizer for potted plants or gardens.
When handling waste, use standard safety precautions (e.g., washing your hands afterward, and avoiding touching your face). Wear a dust mask while tending to your pile if you have a condition that predisposes you to an allergic reaction or infection, especially in dry weather.
Composting is an important tool in environmental conservation and the global fight against climate change among other things. Compost benefits the climate in several ways, including lowering greenhouse gas emissions at landfills, encouraging vegetation to absorb carbon dioxide, and making our projects and gardens more resilient to the effects of climate change.