Survive Peak Oil: Survival Gardening: Composting
All plant material that you don’t eat should be put on the compost heap. This includes various parts of your vegetables, but it also includes weeds. If you pull up the weeds before they go to seed, you’re not going to be re-infesting your garden when you spread the compost; also, if the compost is properly decomposed it will heat up enough to kill any seeds that have already developed. Left for 6 months or a year, the compost will turn into organic soil. As the compost heap is maturing, you might give it water from time to time, and turn it over once in a while, but don’t worry about precision. The compost heap should not be taking up land that you need right away for crops, but at the same time a central location is preferable, so that you don’t have to travel too far when it’s time to spread the compost on the garden. Of course, since valuable minerals will be leaching down into the soil from the compost heap to some extent, don’t build that heap on a piece of land you’ll never be using; it would be foolish to create fertile unused land. Ideally, you would have two or three compost heaps, started about a year apart. The oldest heap is the one that is put on the garden; if you allow that finished compost to dry out, it will be easier to carry. Put the mature compost on the garden in the fall, when you’ve finished harvesting. You might even dig it into the ground, ensuring looser and warmer soil in the following spring.
Because of composting, you don’t have to worry too much about “wasting food.” With supermarket food, anything you throw away is money out of your pocket. With food you have grown yourself, you can be fairly prodigal about throwing away plants that have grown too old or too tough, since all that unused material goes back to the compost heap to become new soil and eventually new vegetables. In fact, the more you add vegetation to the compost heap, the more you increase the organic content of the soil.
One of the purposes of recycling (composting) is to prevent the loss of essential elements. In particular, you must try to preserve nitrogen, phosphorus, and potassium (N-P-K), not because these three are necessarily the most vital elements, but because they are the three that are most likely to be in short supply. It is helpful to bring in material from outside the farm: almost any kind of plant, animal, or mineral material will make some (although not necessarily an adequate) contribution in N-P-K. Farmers in eastern Asia used mud from irrigation canals, animal and human manure, and grass and other vegetation from the hills. Nitrogen, however, which is the most susceptible to loss by leaching, is also the one element that can literally be “got out of thin air.” Any legume, such as beans, peas, clover, or alfalfa, will draw nitrogen out of the air, and if those plants are dug back into the soil (preferably without removing their seeds for food), the nitrogen supply of the soil is renewed.