The greenhouse has finally come full circle, and most of the plants have died off. Not because of any failure, but because like people, they have a limited lifespan. Some late-season crops we planted in September or so are doing well, like the onions and zucchini and carrots, but the rest is ready to be dug up and replanted in January. I hiked up the mountain today with a costál (giant sack), mecapál (carrying strap), and azadón (hoe) and came back with about 50 pounds of rich, loamy rotting leaves to use as fertilizer. It made the earth so tasty looking, I did it again and plan on doing it twice more, once I’ve had some rest. Whew! That’s a lot of carrying for one day.

Part of my excitement is that I am going to try a new gardening system. It’s called “Grow Biointensive“, and has been developed over the past 40 years by John Jeavons and a group called Ecology Action. The objective is to grow a sustainable, balanced diet sufficient to provide complete nutrition while using as little land and wasting as little human energy as possible. This means that crops are carefully selected based on space-to-calorie ratio, presence of vitamins and minerals required by humans, work expended to cultivate vs. calories gained from eating it, things like that. Some crops are grown simply to turn into compost, or to fix nitrogen in the soil for increased fertility in subsequent plantings. Plants are arranged so that tall ones are spaced amongst shorter shade-loving types, and plants that produce early are followed by fall and winter crops in the same bed, to get the most use out of every square foot.

It’s all very elaborate and exciting. Why exciting? Because if it’s done well, a family of four can feed themselves indefinitely with only about 1,200 square feet of earth. That’s astounding. It’s also really applicable to what’s going on in Guatemala today. Everywhere I turn, I see houses being built and farmland disappearing. Sound familiar? Also, it’s a Mayan tradition to have a dozen offspring. When grandpa’s farm gets split between a dozen kids when he dies, and they each have a dozen kids of their own, pretty soon everyone has a farm the size of five parking spaces at Wal-Mart. Obviously, getting more food from less land is only part of the answer; they really need to figure out population control as well.

But is it just Guatemala? I remember hearing about population growth rates and exponential mathematics in the 6th grade (I had a really cool teacher), and I was worried about planetary overcrowding even back then. Then Emily came across this really interesting analogy:

A quote from Suzuki and Dressel’s From Naked Ape to Superspecies:

“The University of Colorago physicist Arthur Bartlett once gave me a graphic illustration of the effects of exponential growth. Imagine a test tube full of food for bacteria. Now imagine that we introduce a single bacterium that will proceed to divide every minute. So at the beginning, there’s one cell. A minute later, there are two; in two minutes, four; and in three minutes, eight. That’s exponential growth. At sixty minutes in this example, the test tube is full of bacteria and all the food is gone. Then when was the test tube half full? The answer, of course, if fifty-nine minutes. So at fifty-eight minutes, it was 25 percent full; at fifty-seven mintues, it was 12.5 percent full. At fifty-five minutes, the test tube was only 3 percent full.

If, at fifty-five minutes, some bacterial genius spoke up and said, “I think we have a population problem,” the less astute majority would probably retort, “What are you talking about? Ninety-seven percent of the test tube is empty, and we’ve been around for fifty five minutes!” But if the doubling continued, then at fifty-nine minutes most bacteria would probably realize they were in big trouble. Suppose they threw money at scientists and begged for a solution. And suppose that, in less than a minute, those bacterial scientists created three test tubes full of food! Everyone would be saved, right? Well, no. The first test tube would be full at 60 minutes. At sixty-one minutes, the second would be full, and at sixty-two minutes all four would be full. By quadrupling the amount of food and space, they gain only two extra minutes.”

Sobering, huh? Just since I’ve been paying attention, the world population had jumped from 4.5 billion humans to 6.7 billion. In the late 1700s, a fellow named Thomas Malthus incorrectly predicted we’de be out of food by the mid-1800s, and several more of his ilk have made similar predictions since then. Many of them turned out to be wrong. The current thinking is that there will be some sort of food/space crisis in 2030 if populations continue to grow at projected levels. I’ll probably live to see it; I guess I’d better get back to gardening.

Here’s a cool article on world population on Wikipedia, by the way.