Compost F.A.Q.

What is Compost?

Compost is man-made humus. Nature’s humus is the product of the ancient process that recycles all things that were once alive. Everything that once was alive dies and rots or decomposes over time. It’s the law of return; the circle of life. Even while a creature is alive the elements of Nature are cycling through it. Air, Water, sun and earth power life. They move through living beings creating new life and powering their bodies. In the cycle of life, these elements are taken apart by Nature’s recyclers and made available for reuse. Humus is the rich living part of the soil that helps keep life alive in the soil. Healthy soil makes healthy food which makes healthy people. Composting is the process of intentionally providing all the materials and conditions necessary to rapidly make humus.

What is Humus?

Humus is the rich, usually dark-colored, component of rich soil. Soil contains minerals (like clay, silt, sand and rocks) as well as living things, newly dead things and really dead things. Humus is made of the last two categories. It forms slowly and naturally under grasslands and forests. The soils richest in humus are in the temporate climate zones that experience a cold winter.

How do you make compost?

In a compost pile bacteria and other living creatures (We’ll call them “the composters”) “eat” the raw materials (leaves, grass, etc.) The goal in building a pile is to accumulate, prepare and position the materials so that the composters have everything they need to grow and reproduce rapidly.

The composters need a carbon source often called browns. Browns are often brown in color like leaves Other examples are straw, sawdust, paper, etc. They contain carbohydrates which yield energy when “eaten”. This is just like the “carbs” humans talk about in our diets, lot’s of energy and very little protein.
The composters need nitrogen. They use the nitrogen-rich foods to build more protein in order to grow and reproduce themselves. Nitrogen comes from a category called greens. Greens are often wet and smelly. Common examples are grass clippings, food scraps and manures. Greens need to be handled rapidly. They can dry out losing both moisture and nitrogen. They can also feed disease organisms and cause bad smells.
The composters need a big home or a large mass of materials. Compost piles are usually built at least three feet in all dimensions. This is because the moist, warm, oxygen-rich conditions can only occur in a large pile. Small piles dry out and cool off quickly. Above about five feet in size oxygen may not be able to penetrate the pile. As the composters eat the materials they breathe out carbon dioxide just like we do. If the pile is too big, it’s hard for air to penetrate fast enough and the pile may lack oxygen or go sour killing the composters and stopping decomposition.
The composters need moisture. The pile should be about 50% water or pretty moist throughout. If you can squeeze the ingredients and get a drop of water to form as you wring out the materials, that’s about right. Actually the composters need a coating or layer of water on all the materials. This lets them stay moist themselves and add their digestive juice to the water. This juice is what dissolves or digests the food. If the materials are dry, they can’t eat or grow. I build my piles with a garden hose and spray nozzle handy. After adding a layer of materials I spray down the whole pile. Most home compost piles fail because they’re too dry.
A container or compost bin is helpful but not necessary. A bin functions to make the pile more cubic instead of just a lump on the ground. Very large piles almost never use a bin because they do have “critical mass”. Backyard piles can really benefit from the mass effect and protection from drying that a bin can provide.

What are the benefits of Compost?

Compost has many benefits when added to soils.

Compost adds both huge numbers of living creatures and the food for more living creatures to the soil. These bacteria, fungi and protozoa can pull nitrogen from the air, minerals from the rock particles and help prevent diseases
Humus is a sponge-like substance that holds moisture. This property can reduce the need for watering by helping the soil absorb rainfall and by holding moisture longer.
Compost has the property of holding particles together. In soils with very small particles, it “glues” many of the small clay particles together providing air spaces for the soil to breathe and for water to soak in. Amazingly compost can help sandy soils retain moisture through the same action.
The compost itself contains mineral nutrients that plants need. Although it is not as concentrated as most commercial fertilizers, its nutrients are easily absorbable and in an organic form that never burns the plant or damages soil life.
Composting yard trimmings, food scraps and many other waste products keeps them out of landfills. Burying these materials in the landfill can cause the production of methane, a powerful greenhouse gas, which also has an awful odor. Diverting these materials into compost is a great win-win action for our environment.

How do you use Compost?

Compost can be used to modify soil or as an additive to soil mixes. Natural soils can contain as much as 4-8% organic matter (humus). It is recommended that no more than 30% of a soil mix be compost. In gardens till one inch into the top three inches of soil or add one fourth inch as a top dressing to the lawn. Compost can be put into trenches or holes near fruit trees to rejuvenate their growth. The root will migrate to the compost.

Why does a compost pile get hot?

When conditions for the growth of bacteria are good they will reproduce rapidly. By reproducing so fast they come to be the equivalent of a large active animal in the middle of the pile, an animal with a body temperature of 150 degrees. Imagine that there are 500 pounds of bacteria in your compost pile eating and breathing and living their lives at high speed. In fact about 30% of compost is the skins of the dead bacteria that ate the raw materials.

Why is Compost a part of global warming reduction strategies?

Of all the things that can happen to organic materials, composting is the best. Burning puts the materials in the air as CO2. Burying in a landfill causes the production of methane gas, which is 20 times worse than CO 2 as a greenhouse gas. In composting about 60% of the carbon is slowly returned to the atmosphere, but the other 40% is very helpful in stimulating rapid plant growth and soil life which can absorb CO2 for many years.

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