Anaerobic (without oxygen): decomposition that is often called fermentation or putrefaction. It is usually accompanied by the release of methane or the foul odor of hydrogen sulfide (rotten egg smell). Anaerobic decomposition occurs slowly and little heat is generated.
Aerobic (with oxygen): a naturally occurring process in nature where organic waste is converted into humus. There is little to no smell. The process creates lots of energy in the form of heat. The heat is an advantage as it destroys pathogens and parasites.
The cast of characters that aid in composting are: bacteria, fungi, millipedes, earthworms and other living inhabitants.
There are 3 types of bacteria:
- Psychrophilic (low temperature bacteria)
- Mesophilic (40 – 110 degrees F) they do most of the work in the compost piles
- Thermophilic (104 – 200 degrees F)
All bacteria need nitrogen and carbon to survive and thrive. Nitrogen provides the microbes with the raw element to multiply. Carbon is the energy source. Bacteria get a complete meal when the carbon to nitrogen ration is 30:1.
Moisture content of 40% – 60% is ideal for bacteria. If it is less than 40%, the bacteria slow down and go dormant. If the moisture content is 60%+, it is too wet which means the pile looses too much air and anaerobic conditions set in.
Turning the pile brings fresh air to the microbes in which their numbers multiply quickly. More microbes = Faster decomposition = Quicker compost
As the pile cools or in the later stages of decomposition, other larger organisms settle in.
- Fungi are major decomposers in the compost pile however, not as efficient as bacteria.
- Nematodes or roundworms
- Fermentation mites
- Wolf Spiders
- Sow bugs
- Ground beetles
A slight detour. One cool factoid about Grass Clippings:
Grass clippings can be directly recycled by letting them fall back in the lawn as you mow. Clippings are 90% water and break down quickly, releasing nutrients equivalent to one or two fertilizations a year.
- Improves soil condition and structure
- Increases the soil’s ability to hold water
- Support living organisms
- Helps dissolves mineral forms of nutrients
- Buffers soil from chemical imbalances
- May provide biological control of certain pests
- Helps return organic materials to the soil and keep them out of landfills and waterways
Here are some simple composting terms:
- Composting: Controlled decomposition of organic materials
- Compost: Partially decomposed organic matter
- Humus: Completely decomposed organic matter
- Mulch: Organic or inorganic spread on soil surface
- Browns or the Carbon component in the composting process: Leaves, sawdust, wood chips
- Greens or the Nitrogen component in the composting process: Manure, food waste, spent flowers, nitrogen fertilizers, grass clippings
The Ideal Mixture of Brown to Green when composting is a ratio of 30:1 (30 Brown : 1 Green)
Now, depending on what method of composting you participate in will determine the material input that can be composted. Of course through industrial composting where machinery, technology, manpower and time are readily available, many more things can be composted including dog waste, meat and dairy products. These three items are not normally recommended for home composting.
This is a sample of items that should be A-OK for your home composting.
- Fruit and vegetables left overs (stalks, seeds, peels, skins)
- Breads, grains, rice, flour, cereal, pasta
- Yard trimmings, wood chips, plants, flowers, leaves, straw, hay
- Natural fibers (cotton, wool, linen)
- Hair (human and animal)
- Herbivore manure
- Coffee grounds and filters as well as tea leaves and bags (no staples)
- Newsprint, paper, cardboard, paper plates, cups and napkins
How to Compost
Types of Compost Units
Compost units can be classified in many ways but the two most popular are “holding units” and “turning units”. Holding units include bins which have been constructed from wire, wood, masonry, plastic, or combo of these materials. Turning units normally include barrels that are turned horizontally or end to end.
When setting up a holding or turning bin, make sure it is in an area protected from drying winds and where it can be reached by a garden hose. It is also a good idea to place the unit/bin in a shady area, away from direct sunlight.
Holding Bin Units
Holding Bins are most popular type of home compost unit. They are the simplest and least expensive type of bin however, they are slower to product compost. Depending on the maintenance, these can take 6 months to 2 years to produce finished compost.
No matter if you are using wire, wood or plastic, the bin composting units should be at least 3 feet wide, 3 feet long and 3 feet high. Larger constructed units will work even better because of better heat retention.
It is very beneficial to construct two or three units/ segments. These type of units facilitate turning and maturing of the composting material. You start at one end of the unit by adding your mixture of browns and greens (30:1). As the first pile decomposes, you move it down to the second section and start all over in the first section. As the second section breaks down even more, you move it to the third section for final curing. Once the third section is finished composting and the compost has been collected, you move the second into the third, the first into the second and start all over again with the first. You’ll always have compost in its different decomposition stages.
Whether you use the sectional holding bin or a single section holding bin, the best way to go about creating a compost pile is the Sandwich Method.
- Alternate layers of green and brown material
- Water each layer until moist (not wet) before adding an additional layer on top
- Keep layering until the pile is about 3 feet tall, ending with a layer of browns(Smaller particles decompose faster so try to mulch or cut up the larger yard and food scraps)
The turning units should produce compost more quickly than a holding unit, if they are attentively managed. They can produce compost in two months or less. Barrel units tend to have smaller capacities than most other bins, including holding bins, which make them better suited for people with small amounts of yard trimmings and food scraps. Turning units are a great option for deterring pests however, organic waste shouldn’t be continuously added but stockpiled until the first batch as been processed. As you can imagine, stockpiling organics in itself can be problematic.
The most commonly used turning units are plastic barrels. Barrel compost units can be turned on either the vertical or horizontal axis depending on the manufacturer set up or how you build one.
Maintaining Your Pile
Once you have decided on which type of compost pile you wish to have – a holding unit or a turning unit – it is time for the fun part – composting!
Composting might appear to a novice as terribly complicated and only for the green thumbed gardener, but anyone can do it! The below outline of how to manage a compost system is mainly for a holding unit.
Location, Location, Location!
Location is one of the most important factors when setting up and maintaining your bin. The most ideal place to put your compost bin is in a shady area where it is shielded from harsh sun and winds. Direct sun can cause your pile to dry out quickly. Having a water hose close by would also be smart so that if watering is needed, you have it nearby. Also, make sure it is in a spot that is convenient for you to add your kitchen scraps. The more efficient and easier it is, the bigger the chance of success!
How to Make Your Neighbours Green with Envy
Once your compost unit is built and in a prime location, you are now ready to add the ingredients! It is recommended that you add mixed green and brown materials in layers, using the sandwich method mentioned above, making sure to water each layer separately as you add them.
In the early days your compost pile will be very warm. It might even steam a little, but no need to sound the fire alarm since this is normal. Heating indicates that the material is composting normally.
In order to maintain your neighbours envy with the perfect compost, you will need to turn your pile frequently with a pitchfork, shovel or tool. By turning the pile frequently you are helping provide oxygen to the compost-creating microbes. More microbes = Faster decomposition = Quicker compost.
Check the temperature of your pile on a regular basis and turn the pile when it reaches about 140F+ or below 100F. If it is too difficult to monitor the temperature on an ongoing basis, just try to turn the pile about twice a week.
Also, regularly check the moisture level. Add water to the pile if it looks too dry. A good rule of thumb is to add water every time you turn the pile. If the compost looks too wet, add more dry browns to the pile.
Make sure you monitor the odor as well. Too much water in the system causes overly strong, odorous piles. If this is the case try adding more browns to the pile like mentioned above.
Identifying finished compost and how to apply it correctly
Here are some simple tips that let you know all your hard work, and the efforts of the microbes, have paid off.
DING, Compost is Done!
The compost should be ready to use after 1 – 12 months, depending on the thoroughness of your management and how finely the pieces of organics were shredded when added to the pile.
The compost pile isn’t generating a substantial amount of heat as it did during the most active cycle.
The material will look dark, will be crumbly, fairly dry and have an earthly odor. You shouldn’t have any recognizable organics.
Where to put It, What to do with it?
Depending on the intended use, the compost can be put through a ½ inch screen before using. The larger particles can be returned to the pile for further decomposition if needed.
Soil Amendment: The compost can be worked into the garden soil adding beneficial nutrients. Do this by adding a layer of 1 – 3 inches. The compost also increases a sandy’s soil ability to retain moisture, improves drainage of clayey soil, increases biological activity of earthworms, reduces the adverse effect of excessive acidity and allows the plant to hold more nutrients for longer periods of time.
Potting Mix: Compost can be blended with perlite, soil, sand and other potting materials to make a great potting mix for your plants.
Mulch: Compost as mulch is extremely valuable because it reduces rainfall runoff, decreases water evaporation loss, helps control weeds and keeps the soil cooler in hot weather and warmer in cold weather. Apply a 2 – 3 inch layer on the top of soil around trees, flowers, shrubs and other plants.
Compost Tea: “Compost tea” can be used to water your plants, adding the advantageous nutrients from the compost. Fill a burlap bag with compost and place in a barrel of water, then use the water to fertilize and hydrate your plants.