poor_old_dad
11-18-2007, 03:06 AM
Here's what it's all about: (Air + Water + Carbon + Nitrogen) + Time = Compost
To start with just let me admit that I'm almost totally compulsive/obsessive about compost. I'll explain why I say "almost" later. If there is a key to Organic Gardening, it is compost. It is the number one source of nutriants and structure for the soil. It is the way we replenish the soil. It is what turns dirt into soil.
Enough... I'm not going to go into a big long speach about the why to make & use compost, etc. If anyone really wants to read it, just ask. For now I'll just talk (well, type) about what it is and how to make it. Note: Keep in mind, this is basic, beginners level, you might say Compost 101.
There are five things basic ingredients that go into making compost: Air, Water, Carbon, Nitrogen, and Time. And it is important to remember that thesew are all variables.
Air. Like most living things, the microbes, bacteria, fungi, worms, and insects that make up the compost ecosystem, need air. Compost scientists (yes, there are compost scientists) say compost piles need porosity. I say what the hell is "porosity"? It turns out that is means the ability for air to move into the pile. I like to think of porosity in terms of fluffiness. A fluffy pile has plenty of spaces for air to move about. A flat, matted pile does not. Even fluffy piles compress during the composting process due to settling and as the material breaks down. Occasionally turning your pile refluffs the material, moves new material into the center, and helps improve air flow into the pile.
Water. Compost microbes, bacteria, fungi, worms, and insects also need the right amount of water. Too much moisture reduces airflow, causes temperatures to fall, and can make the pile smell; too little water slows decomposition and prevents the pile from heating. Conventional wisdom says that compost should feel like a wrung-out sponge.
Carbon ingredients. The microbes that break down organic matter use carbon as an energy source. Ingredients with a high percentage of carbon are usually dry and brown or yellow in color. The most common high-carbon ingredients are leaves, straw, and corn stalks. Sometimes people call these ingredients browns.
Nitrogen ingredients. Microbes need nitrogen for the proteins that build their tiny bodies. Ingredients high in nitrogen are generally green, moist plant matter, such as leaves, or an animal by-product, such as manure. These ingredients are called greens, but in reality they can be green, brown, and all colors in between.
Time. If mix together some straw, corn stalks, and some manure, get it moist, then stir in some air, you will NOT have compost. It takes time for the microbes, bacteria, fungi, worms, and insects to "do their thing", so to speak. The amount of time can vary from about 2 months to about 2 years, depending on a few things. Probably the most important is the C/N ratio. In order for a compost pile to decompose efficiently, you need to create the right ratio of carbon (C) to nitrogen (N) (C/N). Piles with too much nitrogen tend to smell, because the excess nitrogen converts into an ammonia gas. Piles with too much carbon break down slowly because there's not enough carbon for the microbe population to expand. An ideal compost pile should have a 30:1 C/N ratio or 30 pounds carbon to 1 pound nitrogen. Grass clippings alone have about a 20:1 C/N ratio. Adding one part grass clippings, to two parts dead leaves, will give you the right mix.
Another thing that effects the time is how well you monitor the moisture. If you allow the pile to dry out the microbes stop working because they die. If you get it too wet, the air spaces will be gone and the microbes stop working because they die. To be accurate, the composting work will slow way down because most microbes, etc. die. Except under very extreme conditions there will always be some air and moisture.
Another thing that effects the time is how small the stuff in the pile is. A pile of finely chopped grass, straw, leaves, whatever will compost more quickly.... much more quickly.
Another thing that effects the time is how often you turn or stir the pile. When you turn the pile you are getting air in and the fluffing action gives small (really tiny) air spaces. You are also helping (speeding up) bringing the microbes, etc., and the to-be-composted stuff together. On the other hand, you can turn the pile too often. What that will do is cause the pile to dry and reduce heat build up.
And speaking of heat. There are two main ways to make compost: cold compost (minimum effort) and hot compost (maximum effort).
Cold: Nearly every gardener I have talked to has admitted (sometimes sheepishly) that they do this type of composting in their own backyards because it's easy. Here's how to make cold compost: Mix together yard wastes, such as grass clippings, leaves, and weeds, place them in a pile, and wait 6 to 24 months for the microorganisms, earthworms, and insects to break down the material. Add new materials to the top of the pile. You can reduce the waiting period by occasionally turning the pile and monitoring and adjusting the pile's moisture level. The compost will be ready when the original ingredients are unrecognizable. Generally, compost on the bottom of the pile "finishes" first.
Pros: Takes little effort to build and maintain; can be built over time.
Cons: Takes up to two years to produce finished compost; doesn't kill pathogens and weed seeds; undecomposed pieces may need to be screened out.
Hot: Hot, or fast, composting takes more work and the right combination of ingredients, but you can get high-quality compost in under two months. Here's how: Wait until you have enough material to create compost critical mass (27 cubic feet), which is the minimum volume for a pile to hold heat. Then mix one part green matter with two parts brown matter. Bury any vegetative food scraps in the center to avoid attracting animals. Check to make sure the mixture has the ideal moisture level. Continue adding mixed greens and browns and checking the moisture until you've built a pile that is 3 feet x 3 feet x 3 feet, or 5 feet wide at the base and 3 feet wide at the top. The microorganisms will immediately start decomposing, and their bodies will release heat. The pile will insulate the heat, and the temperature of the pile's interior will reach 120 to 150 degrees F. Turn the pile weekly and regulate moisture levels. After about a month, the hot phase will be done, and the pile will finish decomposing at temperatures between 80 degrees F and 110 degrees F. The compost will be ready to use when it no longer heats and all of the original ingredients are unrecognizable.
Pros: Produces high-quality compost within 2 months (and sometimes as soon as a few weeks); can kill weed seeds and pathogens.
Cons: Time-consuming; requires careful management of moisture, air, and C/N ratio.
Next we'll go into what to put in and what to not put in to a compost pile.
Peace,
poor_old_dad
To start with just let me admit that I'm almost totally compulsive/obsessive about compost. I'll explain why I say "almost" later. If there is a key to Organic Gardening, it is compost. It is the number one source of nutriants and structure for the soil. It is the way we replenish the soil. It is what turns dirt into soil.
Enough... I'm not going to go into a big long speach about the why to make & use compost, etc. If anyone really wants to read it, just ask. For now I'll just talk (well, type) about what it is and how to make it. Note: Keep in mind, this is basic, beginners level, you might say Compost 101.
There are five things basic ingredients that go into making compost: Air, Water, Carbon, Nitrogen, and Time. And it is important to remember that thesew are all variables.
Air. Like most living things, the microbes, bacteria, fungi, worms, and insects that make up the compost ecosystem, need air. Compost scientists (yes, there are compost scientists) say compost piles need porosity. I say what the hell is "porosity"? It turns out that is means the ability for air to move into the pile. I like to think of porosity in terms of fluffiness. A fluffy pile has plenty of spaces for air to move about. A flat, matted pile does not. Even fluffy piles compress during the composting process due to settling and as the material breaks down. Occasionally turning your pile refluffs the material, moves new material into the center, and helps improve air flow into the pile.
Water. Compost microbes, bacteria, fungi, worms, and insects also need the right amount of water. Too much moisture reduces airflow, causes temperatures to fall, and can make the pile smell; too little water slows decomposition and prevents the pile from heating. Conventional wisdom says that compost should feel like a wrung-out sponge.
Carbon ingredients. The microbes that break down organic matter use carbon as an energy source. Ingredients with a high percentage of carbon are usually dry and brown or yellow in color. The most common high-carbon ingredients are leaves, straw, and corn stalks. Sometimes people call these ingredients browns.
Nitrogen ingredients. Microbes need nitrogen for the proteins that build their tiny bodies. Ingredients high in nitrogen are generally green, moist plant matter, such as leaves, or an animal by-product, such as manure. These ingredients are called greens, but in reality they can be green, brown, and all colors in between.
Time. If mix together some straw, corn stalks, and some manure, get it moist, then stir in some air, you will NOT have compost. It takes time for the microbes, bacteria, fungi, worms, and insects to "do their thing", so to speak. The amount of time can vary from about 2 months to about 2 years, depending on a few things. Probably the most important is the C/N ratio. In order for a compost pile to decompose efficiently, you need to create the right ratio of carbon (C) to nitrogen (N) (C/N). Piles with too much nitrogen tend to smell, because the excess nitrogen converts into an ammonia gas. Piles with too much carbon break down slowly because there's not enough carbon for the microbe population to expand. An ideal compost pile should have a 30:1 C/N ratio or 30 pounds carbon to 1 pound nitrogen. Grass clippings alone have about a 20:1 C/N ratio. Adding one part grass clippings, to two parts dead leaves, will give you the right mix.
Another thing that effects the time is how well you monitor the moisture. If you allow the pile to dry out the microbes stop working because they die. If you get it too wet, the air spaces will be gone and the microbes stop working because they die. To be accurate, the composting work will slow way down because most microbes, etc. die. Except under very extreme conditions there will always be some air and moisture.
Another thing that effects the time is how small the stuff in the pile is. A pile of finely chopped grass, straw, leaves, whatever will compost more quickly.... much more quickly.
Another thing that effects the time is how often you turn or stir the pile. When you turn the pile you are getting air in and the fluffing action gives small (really tiny) air spaces. You are also helping (speeding up) bringing the microbes, etc., and the to-be-composted stuff together. On the other hand, you can turn the pile too often. What that will do is cause the pile to dry and reduce heat build up.
And speaking of heat. There are two main ways to make compost: cold compost (minimum effort) and hot compost (maximum effort).
Cold: Nearly every gardener I have talked to has admitted (sometimes sheepishly) that they do this type of composting in their own backyards because it's easy. Here's how to make cold compost: Mix together yard wastes, such as grass clippings, leaves, and weeds, place them in a pile, and wait 6 to 24 months for the microorganisms, earthworms, and insects to break down the material. Add new materials to the top of the pile. You can reduce the waiting period by occasionally turning the pile and monitoring and adjusting the pile's moisture level. The compost will be ready when the original ingredients are unrecognizable. Generally, compost on the bottom of the pile "finishes" first.
Pros: Takes little effort to build and maintain; can be built over time.
Cons: Takes up to two years to produce finished compost; doesn't kill pathogens and weed seeds; undecomposed pieces may need to be screened out.
Hot: Hot, or fast, composting takes more work and the right combination of ingredients, but you can get high-quality compost in under two months. Here's how: Wait until you have enough material to create compost critical mass (27 cubic feet), which is the minimum volume for a pile to hold heat. Then mix one part green matter with two parts brown matter. Bury any vegetative food scraps in the center to avoid attracting animals. Check to make sure the mixture has the ideal moisture level. Continue adding mixed greens and browns and checking the moisture until you've built a pile that is 3 feet x 3 feet x 3 feet, or 5 feet wide at the base and 3 feet wide at the top. The microorganisms will immediately start decomposing, and their bodies will release heat. The pile will insulate the heat, and the temperature of the pile's interior will reach 120 to 150 degrees F. Turn the pile weekly and regulate moisture levels. After about a month, the hot phase will be done, and the pile will finish decomposing at temperatures between 80 degrees F and 110 degrees F. The compost will be ready to use when it no longer heats and all of the original ingredients are unrecognizable.
Pros: Produces high-quality compost within 2 months (and sometimes as soon as a few weeks); can kill weed seeds and pathogens.
Cons: Time-consuming; requires careful management of moisture, air, and C/N ratio.
Next we'll go into what to put in and what to not put in to a compost pile.
Peace,
poor_old_dad