Bring Beneficial Organisms into Your Garden

Learn how beneficial organisms such as worms and even bats can help maintain the balance of your ecosystem.

Green Wizardry

“Green Wizardry,” by John Michael Greer, is a valuable resource for anyone concerned about decreasing our dependence on an overloaded industrial system and making life a great deal less traumatic and more livable.

Cover courtesy New Society Publishers

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Green Wizardry (New Society Publishers, 2013), by John Michael Greer, proposes a modern mage for uncertain times, one who possesses a vast array of practical skills gleaned from the appropriate tech and organic gardening movements forged in the energy crisis of the 1970s. From the basic concepts of ecology to a plethora of practical techniques such as composting, green manure, low-tech food preservation and storage and more, Greer provides a comprehensive manual for today’s wizard-in-training. The following excerpt from Lesson 14, “Wild Helpers,” describes how beneficial organisms can assist you with your organic garden.

You can purchase this book from the MOTHER EARTH NEWS store: Green Wizardry.

There’s a great line in Shakespeare’s Henry IV, Part One where the English nobleman, Hotspur, and the Welsh wizard, Owen Glendower, are quarreling. “I can call spirits from the vasty deep,” Glendower insists, and Hotspur comes right back: “Why, so can I, and so can any man; But do they come when you do call them?” Funny as it is, the quarrel points up one of the things that wizards have traditionally been able to do, and, as a green wizard, you need to be able to do something similar. By the time you’ve finished with this lesson, you may not be able to call spirits from the vasty deep, but you’ll have started learning to call helpful critters from the surrounding ecosystems to help maintain the balance of your garden — and yes, to forestall Hotspur’s gibe, they will indeed come when you do call them, if you do it in the right way.

Let’s start by reviewing some basic concepts. A garden is an ecosystem managed so that human beings get to eat a significant portion of the net primary production of the plants that grow there. Net primary production? That’s the amount of energy each year that the plants in an ecosystem take in from the sun and store in the form of sugars and other compounds that can be eaten by some other living thing. Everything other than plants in any ecosystem gets its fuel from the net primary production of that ecosystem, or of another ecosystem that feeds energy into it.

You’re not going to get anything close to a majority of the net primary production of your garden onto your dinner table, by the way, and it’s a mistake to try. If you do, you’ll starve other living things that depend on a share of net primary production to keep their own dinner tables stocked, and you need these other living things in order to have a healthy and productive garden. Your goal instead is to make sure that as much as possible of the net primary production diverted from your table goes to living things that earn their keep by doing something for your benefit.

Here’s an example. A certain amount of each year’s net primary production from your garden goes to feed earthworms. Any gardener with the least jot of common sense won’t grudge them their share, because earthworms break down organic matter into forms plants can use, and they improve the texture and drainage of soil as they do it. Charles Darwin — yes, the same Charles Darwin who wrote The Origin of Species — wrote a brilliant book on the role of earthworms in the creation of topsoil. What he found, to drastically simplify a classic piece of ecological research, is that earthworms are topsoil-making machines, and the more you’ve got, the better your soil and the higher your crop yields will tend to be.

According to the logic of modern industrial society, you might think that gardeners ought to run out and buy earthworms by the carload, but the logic of modern industrial society is just as wrong here as usual. There are bound to be earthworms in your soil, and since earthworms are hermaphroditic and fertile most of the time, there’s generally no shortage of baby earthworms starting out on their slimy and subterranean lives. The question, if you’ve got a worm shortage, is why so few grow up to become the big pink nightcrawlers that haunt fishermen’s dreams.

This is where another of the fundamental principles of ecology comes into play. Liebig’s law, named after the 19th-century German agricultural botanist Justus von Liebig, has the interesting distinction of being at one and the same time one of the most consistently valid principles of ecology and one of the most consistently rejected concepts in modern economics. The short form of the law is that for any organism, whatever necessary resource is in shortest supply puts an upper boundary on the carrying capacity of the environment for that organism.

To understand how this works, imagine a plant growing in your garden. That plant has a variety of needs — water, nitrogen, phosphorus, potassium, an assortment of trace elements, and so on. If the soil is short of any one of them, it doesn’t matter if all the others are abundant. The nutrient in short supply will determine how well that plant can grow in that garden. All the living things in your garden are subject to Liebig’s law, and if you want more of something living in your garden, you need to find out what resource is in shortest supply, and provide it. For earthworms, most often, the sheer amount of organic matter in the soil is the limiting factor, since decaying organic matter is what earthworms eat. Thus, the more organic matter you put into the soil — compost, mulches, green manures, or what have you — the more infant earthworms will mature to massive pink nightcrawlerhood and get to work improving your garden soil.

The Case for Bats and Bees

The same rule governs all the other useful critters you might want to attract to your garden. Bats are a good example. Why so many people fear and dislike bats is beyond me. Any animal that eats its own weight in mosquitoes in a single night ought to be a welcome guest anywhere. Still, the benefits bats bring to the garden outweigh even the simple pleasure of not being eaten alive by the insect world’s answer to Count Dracula. Many of the grubs that cause serious damage to food crops — the corn borer, the apple maggot, and more — are the larva of night-flying moths, and nightflying moths are prime bat food.

The limiting resource for bats, far more often than not, is daytime shelter during the non-hibernating months, so one very easy way to bring bats to your garden is to build or buy a bat house and set it in an appropriate place. Both the house and its placement require a certain degree of care, but their preferences are well known. Get a proper bat house in place, and, in most cases, you can count on a crew of bats finding it and taking up residence promptly, and thereafter any problems you may be having with moth larvae will become a good deal less severe.

Birds are the day shift to bats’ night shift, and some varieties of birds are well worth attracting to your garden as well. Swallows, swifts, and martins — a closely related group of birds with tapering, pointed wings and a prodigious appetite for insects — are classic examples. Until the advent of chemical agriculture, farmers across North America encouraged barn swallows to set up housekeeping on their farms because swallows do exactly what their name suggests to many daytime insects that make life difficult for crops. Like bats and most species of birds, swallows and their relatives are particular about their homes; here, though, this is a double advantage because homes suited to swallows are uninviting to starlings and other birds that damage crops.

Another set of living things your garden needs is pollinators. The collapse of honeybee populations over much of the industrial world has been all over the news in recent years, and for good reason. Without pollination by insects, many food crops don’t produce or reproduce, and honeybees have long been the primary pollinators of most commercially grown fruits and vegetables, with hives being trucked from farm to farm over hundreds of miles in season.

Exactly what is causing Colony Collapse Disorder is uncertain as yet, though a growing body of evidence points to a class of recently introduced and heavily marketed pesticides — neonicotinoids such as imidacloprid — which are highly toxic to bees and can build up to lethal levels in a hive’s honey supply. Until the issue gets sorted out, making sure that your garden has backup pollinators is crucial. Domesticated honeybees are one option, but beekeeping is not a project for everyone. Another, far less demanding option is to increase the population of local species of wild bees and other pollinating insects.

Spend some time outdoors watching flowering plants, and you’ll quickly discover just how diverse a range of insects can play the pollination game. Many of them are bees of one kind or another, for there are thousands of kinds of bees. Very few of them have the complex social structure and hive life of the honeybee, and even fewer of them have a sting painful to human beings. Most are solitary, harmless, and short-lived, hatching in the spring and mating almost immediately, after which the males die and the females spend the rest of their lives laying eggs in burrows of one kind or another. Each egg will hatch out the next spring as a bee of the next generation, thus completing the cycle. There are things you can do fairly easily to keep this cycle going, and a little research will quickly turn up options appropriate to your area.

Pollinators need something in flower to feed on for the entire period they are active, which varies by species: for orchard mason bees, for example, it extends from March to the end of May in most areas, while for bumblebees, depending on the species, can run from sometime in the late spring well into autumn. The absence of flowering plants can be a limiting factor for all kinds of bees, and if the area around your garden is short on flowers at some point in the season, a flowering shrub or two to fill in the gaps is a good investment. We have a buddleia in our front yard that serves as lunch counter for a dizzying array of daytime insects, including nearly a dozen species of wild bees; your local ecosystem will have appropriate shrubs that will fill the same role.

The same principle can be applied in many other ways. Just as you can encourage a species by figuring out which resource it needs is in shortest supply and providing that resource, you can limit an unwelcome species by figuring out its resource needs and doing your best to make sure that one of those needs is as scarce as possible. As you work with your garden and learn more about the complex ecosystem that an organic garden develops around it, pay attention to places where a little careful tinkering with variables can increase the population of something you want — and decrease the population of something you don’t want. It’s not so clumsy or random as a pesticide, to borrow and redefine a phrase from Star Wars’s Obi-Wan Kenobi: an elegant method of the more ecologically sane age toward which, willy-nilly, the pressures of the present are forcing us.

Read More from Green Wizardry:

Start a Compost Pile to Help Your Garden Grow
Be Better Prepared with a Fireless Cooker


Exercise for Lesson 14

Your task for this lesson is to research at least one kind of wild creature — insect, bird, mammal, or what have you — that benefits gardens in your area. The earthworms, bats, swallows, and pollinating insects discussed in the lesson are good examples, but there are many other living things that improve the soil, perform useful services for plants, or devour pests. A little research and a little imagination will turn up plenty of other candidates. When you’ve chosen your helpful critter, using the internet, the local library, and any other resources that come to mind, try to find out what resources your creature needs in order to survive. Which of those resources might be in short supply in your area? How might you increase the supply of the limited resource, so that you can attract more of your chosen creature to the vicinity of your garden?


Reprinted with permission from Green Wizardry: Conservation, Solar Power, Organic Gardening, and Other Hands-on Skills from the Appropriate Tech Toolkit by John Michael Greer and published by New Society Publishers, 2013. Buy this book from our store: Green Wizardry.