Compost Manual
What Is Composting?
Compost is decayed, organic plant matter. Composting is the result of a complex feeding pattern where aerobic microbes (bacteria and fungi that thrive on oxygen) feed on organic waste and break it down into a nutritious soil amendment. As the compost is mixed and aerated, these organic materials break down into a rich substance the same way that plants decay and are recycled in any ecosystem. This in turn creates fluffy, arable soil known as humus. All organic matter breaks down into compost over time, but the decomposition process on its own can take quite a while. Composting creates a controlled environment to rapidly convert waste into a powerful, nutrient-rich matter that is ideal in your garden, on your lawn, or in your potted plants.
Along with fuel efficiency, water conservation, and reduction in meat consumption, home composting is one of the most environmentally beneficial activities you can participate in. Yard and food waste make up approximately thirty percent of the waste stream in the U.S. If every household participated in composting, it would divert a significant portion of the waste stream from our landfills and water treatment facilities. If you combined composting with recycling cans, newspapers, and plastic, you could reduce your waste flow by almost fifty percent! By composting, you are preventing our crowded landfills from overflowing and giving something back to nature.
Proper compost is an incredibly nutritious soil amendment, buffering the pH and retaining moisture and oxygen in the soil. It can cool the soil surface and help mitigate erosion by encouraging a vigorous root system boosted by nitrogen, potassium, phosphorus and other nutrients. Composting helps control and suppress plant pathogens, as well as provide food for microorganisms, which keep the soil healthy and balanced. It improves the structure of problematic soils, breaking up heavy clay soils and retaining water better in sandy soils. Compost is chemical free—children and pets can enjoy the beautiful bounty of your organic lawn without exposure to toxins or synthetic products, making it an excellent, cheaper alternative to commercial fertilizers.
Homeowners everywhere are starting to realize how convenient and economical it is to compost waste they would have otherwise thrown away. Why buy premium topsoil when you create your own endless supply for free? Home composting also serves as an invaluable educational tool, teaching children about conservation, the cycle of life, and the inter-connectedness of the natural world. If it gets your child thinking about science or biology, or voluntarily participating in yard work, it’s well worth the effort!
How To Compost
Composting is a dynamic process; it takes skill and the ideal conditions to aid the decomposition process. The good news is that decomposition naturally occurs with or without your help, so half the battle already won. Once you understand the major factors behind composting, you can apply them to adjust your efforts and turn your compost bin, tumbler, or open pile into an efficient composting machine.
The real trick is to get your pile to decompose as fast as you can fill it. When you neglect your compost pile, it will decompose very slowly, otherwise known as “passive composting”. Fast or “active” composting can happen much more quickly because the aerobic bacteria breakdown much faster. Passive composting involves little energy or effort, but takes much longer. Active composting, on the other hand, requires a bit more work but yields results faster. How you compost depends on your needs. If you want to produce as much compost as possible, you want to be actively managing your compost. If you are looking to get rid of yard waste, go with passive composting.
The rate at which breakdown occurs depends on several factors: oxygenation, temperature, water content, particulate surface area, and the carbon to nitrogen ratio. If you pay attention to these things, the temperature will rise to around 130-140 degrees, ensuring rapid decomposition. Moisture is key—your compost should feel damp, but never wet. When it’s over inoculated, it limits the oxygen that bacteria require. The rule of thumb is that it should be as wet as a well-wrung sponge. Similarly, if your compost is too dry, bacteria cannot survive, thereby slowing down the decomposing process. If your pile doesn’t heat up, it’s possible that your compost pile is too wet, too dry, or there is not enough protein (greens). You can measure the temperature with a compost thermometer.
Aeration is equally important, as your compost needs oxygen to decompose. Keep your compost pile breathing by turning it by hand with a pitchfork. A compost tumbler takes out this step by aerating the compost for you as it tumbles in the bin. Look for ones with vents on the side to keep your compost properly aerated. If you don’t have a compost tumbler, try a metal aerator that will help take some of the work out of turning the pile.
Choosing a good composting site will help speed up the process. Start building your compost over soil or lawn instead of on a patio so you can take advantage of earthworms and microbes. Look for an area that’s level and well-drained. If you’re adding kitchen scraps, keep it near the back door, but not so far away you’ll forget it’s there. If you live in a cooler climate, put the pile in a sunny spot so it can trap solar heat, and find it some shelter during the winter months so the decaying process doesn’t slow down. If you live in a warmer climate, keep the pile in a shadier spot so it won’t dry out. And remember to look for a spot that will allow you to compost unobtrusively; try to distance it from the neighbor’s yard and put up visual barriers. A compost bin will keep it contained, and is easier to manage than an open compost pile.
Shredded organic materials heat up and decompose faster. The smaller the composting pieces, the faster the pile with decay. Add new materials, remembering to layer them. Mixing distributes microorganisms evenly allows for faster decomposition at the same time, so that there is a more balanced carbon to nitrogen rate, as well as better moisture and air migration. The goal is to create an active, hot batch of compost, so the more effort you put into your pile, the more black gold you’re going to get!
After you’ve attained the right mix of browns and greens, the right amount of moisture, and the ideal aeration and heat from turning, your batch of compost will be well on its way to becoming the soil amendment your plants so desperately crave. However, it would be irresponsible to give an exact time frame for when waste becomes humus, as several factors will impact how quickly breakdown occurs. Peak seasons for composting are spring and autumn, when the atmosphere is warm and damp. Piles created during this time, with shredded materials that are frequently aerated, can be ready in approximately 2-4 months. Properly tended soft waste in warm weather can take as little as 4-6 weeks. Piles prepared in the winter or late fall, created with larger or tougher pieces of waste, or left unattended, will take longer to decay.
When your compost is done, it will be approximately half of its original size. You should not be able to discern individual items you placed in the bin. Look for a dark color, crumbly texture, and earthy smell. Slimy compost is a sign that the process was done incorrectly at some point. If you experience trouble with clumps or mats, organize your organic wastes into thinner layers, and use aerators or a pitchfork to work your pile.
Many people think that composting is a smelly process—it’s not true! If you properly manage your compost pile, you should not be producing offensive odors. Compost should have an earthy, pleasant smell similar to a forest floor after rain. If you do smell something suspicious, odor problems are easily fixed, so don’t become discouraged.
Soon after your compost pile is established, you should begin seeing sundry little critters throughout the pile contents. These helpers, which usually migrate from other parts of the garden or the soil beneath the pile, can range from arthropods and flying insects to microorganisms like bacteria and fungi. Don’t be alarmed! They are all part of the soil-borne community that is critical to the decomposition process. Do not attempt to eradicate or remove these beneficial creatures, and do not use any chemicals or sprays that would normally harm them. Let them flourish and your compost will flourish with them. If possible, use rainwater from a rain barrel to moisten the pile, as chlorinated municipal water sources can slow down the natural rate of breakdown.
For your convenience, we’ve provided a chart describing the factors that could affect your compost. Use it as a quick reference and guide:| Factors Affecting Rate | description |
|---|---|
| Oxygenation | Oxygen is required for respiration by all aerobic inhabitants within the pile. Aerobic microbes decompose waste at a faster rate than their anaerobic brethren, and would not produce the foul odors associated with anaerobic decomposition. Adequate ventilation and manually turning or mixing your pile with aerators or pile turners twice a month increases its rate of decomposition. An unmixed pile may take three to four times longer before it breaks down. If purely manual mixing is not to your fancy, you can invest in a compost tumbler that aerates by turning. |
| Temperature | Heat is a byproduct of decomposition and accelerates the process. The optimum temperature for fast decomposition is between 90 and 135 degrees F. Whether it is due to cold climate or insufficient bacterial activity, when the temperature falls below this, decomposition will slow, but not cease. To keep temperatures elevated, try an insulation jacket or better placement for maximizing radiant solar heat. Also choose black colored bins in cooler climate zones. |
| Water Content | An efficient composter needs to have a moisture content of approximately 50% (it should feel like a damp towel) for microbial activity. If it is too dry, decomposition will slow down considerably, while overly wet piles can trigger anaerobic conditions and begin to smell. Keep the pile covered during heavy rains, so that valuable nutrients are not washed away. Add rain water from your rain barrel when dry spells occur (chlorine in municipal water can kill the organisms in your living system). |
| Surface Area | Maximize this by shredding and chipping all clippings and waste into small pieces with a chipper/shredder. The more surface area you expose for microorganisms to attack, the faster the decomposition. |
| Carbon: Nitrogen Ratio | Organic materials rich in nitrogen are referred to as GREENS (fresh veggie scraps or grass clippings), while the others can be lumped together as BROWNS (hay, twigs, dried leaves). A good general rule of thumb is use 2-3 parts brown to 1 part green. When initially building your pile, always remember to layer, layer, layer! Alternating layers ensures proper mixing. |
Let’s review how to setup a composting station:
- Choose a moderately sunny, accessible area for your composter. If you’re using a compost bin, turn the soil in your chosen location.
- Start your green and brown layering process, beginning with a layer of small branches at the bottom that will allow for proper circulation and drainage.
- Top off your new pile with finished compost or good garden soil to ensure an introduction of bacteria to your waste.
- Aerate regularly by mixing, checking moisture content.
Harvest the finished compost, and you’re all set to enjoy a beautiful, healthy garden!