Sir Albert Howard, the British agronomist who worked in India from 1905 to 1934, is known as the "father of organic gardening." He noticed the differences between plants nourished by organic material and those fed artificial substances. On the bases of his observations, he developed the methods of composting that are the precursors of that described here. He could see the results of his methods in the healthier plants, animals and people that they led to. Today, with the organic movement picking up steam, we can anticipate that the benefits of organic growing can become available to everybody.
As gardeners, we can take advantage of those natural processes to build good, healthy soil for the plants we grow, and we don't have to wait centuries for the process to take place. But first, we need to understand how the process works.
There are millions of tiny beings in the soil and in the very air we breathe, micro-organisms that feed on organic material and thereby do the work of breaking down molecule-sized bits of matter, transforming them into a form that plant roots can take up and use to build plant bodies and add nourishment to the food we eat and feed to animals. The organisms work by simply digesting the matter they contact and eliminating residues in a form the plants can use. Throughout their short lives they digest and eliminate, creating decomposition; when they die, they add their small bodies to the collected composted material they have processed. The trick is to supply enough of those organisms with enough food in the right conditions for them to do their work.
What are the right conditions? Basically, the process requires adequate moisture and adequate oxygen. (I'm describing an aerobic process; you can compost anaerobicallyÑwithout oxygenÑbut that takes longer and has some side effects we want to avoid.) The microbes need the oxygen for their growth and survival, just as we do, and the moisture is necessary as a medium in which the oxygen can dissolve and become available to the worker organisms. All of that happens in nature, but only very slowly. For our uses, we want to speed things up.
So, if we get together a pile of organic material and keep it moist and aerated, we've got it down. What kind of material is best? Start with plant materials, plant cuttings, straw, sawdust, food wastes, manures and the like. Put them all together in a pile, a wire cage or a bin, and add some water. That starts the process automatically. The little critters start chewing away at whatever they find there. But after awhile, the oxygen begins to run out. If it isn't replenished, the process stops, or slows to a crawl. That's where turning comes in. By turning the pile, we introduce more oxygen as well as a whole new population of eaters to replace those that have died out. Then the process starts over again.
The moisture content has to be right. Too much water results in a sodden mass, as the water fills up all the spaces and there is no room for air. With too little water, the microbes don't survive as well and the process slows considerably.
Since we're in a hurry, relatively speaking, it's a good idea to grind the materials of the pile down to as small a size as we can manage. That provides more surfaces for the worker-diners to chew on and speeds the process. However, with smaller chunks, we need to be careful with the moisture level, as it is easier to supersaturate the material.
Nitrogen fuels the process. The more nitrogen in the pile, the faster the process works. If all you have is a pile of dry grass cuttings, the action is slow, very slow. Add some nitrogen, in the form of manure, green manure or urine, and the pile gets hotter, the process faster. Heat helps things along.
A note about heat: the hotter the pile, the faster it works and, as well, the better the chance that you are killing any weed seeds or disease organisms in the pile. A good, well-contained pile should heat up to about 180 degrees, which is supposed to be hot enough to kill any seeds and any germs that might be harmful to humans. There is, however, some disagreement about how high a temperature is needed to kill off certain pathogens. For that reason, it's not a good idea to try to compost human, dog or cat feces in your backyard pile. Other cautions apply if you don't use a closed compost bin: meat and meat products, grains and breads attract mice and rats, so it's best to leave those things out, or use a bin system. I use a two-bin system, turning from one to the other, and I find that I can produce some fine compost in three weeks, turning the stuff twice a week. That does wonders for my soil.
For more production, I have used rows of boxes lined up next to one another, turning each into the next until the finished compost comes out at the end of the line. That provides you with a continual supply, once you get started, but sometimes it's a hassle getting enough ingredients together to keep it going.
What do we get from all that? The final product should be a dark, crumbly, sweet-smelling material, so healthy-looking you'll want to roll it up and smoke it. But if you put it in your garden, you'll get fine soil, lightened by the humus from the compost and packed with nutritious elements for your plants. The humus works as a catalyst to unlock nutrients that are chemically bound within the soil particles.
In addition to the major nutrients, nitrogen, phosphorous, potassium, calcium, etc., the compost provides all manner of trace elements which work together to make for healthy, productive plants. As we eat those plants and their products, we benefit from their vibrant health; our bodies are healthier and stronger, better equipped to hold off the various ailments that lurk everywhere to sap our energies and bring us down. We can help bring that about, as individuals in our daily lives or as communities dealing with waste disposal problems, by composting.
The Two Elements of Compost
Carbon:
Ðsaw dust
Ðplant cuttings
Ðstraw
If compost smells like ammonia, add more carbon.
Nitrogen:
Ðfood scraps
Ðurine
Ðmanure
Ðgreen grass cuttings
If compost isn't getting hot, add more nitrogen.
Copyright Mendocino Environmental Center 2003
Permission granted to excerpt or use this article if source is cited