The Earth Moved: On the Remarkable Achievements of Earthworms

by Amy Stewart (Algonquin Books, 2004, 221 pgs.)

Aristotle called worms “the intestines of the earth.” Charles Darwin wrote, “Without the work of this humble creature, who knows nothing of the benefits he confers upon mankind, agriculture, as we know it, would be very difficult, if not wholly impossible.” In The Earth Moved, Amy Stewart (author of the bestsellers Wicked Plants and Wicked Bugs) aims a spotlight at these fascinating creatures, which are so often ignored, misunderstood, or written off as mere fish bait.

A story about earthworms is essentially also a story about soil, and serious gardeners are often obsessed with soil. Stewart interweaves her exploration of the ecological role of earthworms with the more personal story of her own worm-keeping endeavors-she uses the castings from her small worm composter in her garden. She provides some useful tips for readers who are tempted to try this composting method in their own gardens. She also discusses other life forms that play  a role in soil health, such as nematodes, bacteria, and fungi.

Stewart starts the book with an engaging discussion of Charles Darwin’s earthworm research, which culminated in the 1881 publication of his book with the kind of lengthy title that was typical in the nineteenth century: The Formation of Vegetable Mould, Through the Action of Worms, With Observations on Their Habits. In addition to observing earthworms for decades, Darwin conducted a wide variety of earthworm experiments, such as tests designed to determine whether they could discern a variety of shapes and whether they were influenced by noise.

Earthworms were apparently first distributed throughout the world as a result of geological changes that occurred many millions of years ago. Now there are a wide variety of worm species all around the globe, including giant three-foot-long earthworms in Australia and bright blue ones in certain tropical rainforests. One issue that Stewart explores in some depth is the problem of invasive earthworm species and their impact on the environment, particularly in the United States. This is a manmade problem, as the earthworms are transported both purposely and by accident as a result of human endeavors that range from fishing to commerce. Non-native earthworm species are having a negative impact on forest ecosystems and other environments nationwide and are pushing aside native species that play a vital role in the web of life. “Dig up an earthworm from any backyard in the United States, and that worm will most likely be non-native,” Stewart writes.

Stewart includes a wealth of scientific information about earthworms here, but manages to make it engaging rather than tedious. She includes insights from a variety of earthworm researchers (scientists known tongue-twistingly as oligochaetologists), as well as anatomical and life-cycle details. She also touches on earthworms’ vital role in agriculture. There can be millions of earthworms per acre, and their castings contribute to healthy soil. “Worms, through their actions, substantially change the earth,” Stewart writes. “They alter its composition, increase its capacity to absorb and hold water, and bring about an increase in nutrients and microorganisms.” Stewart also includes an interesting discussion about attempts at large-scale worm composting, where cities are using worms to process solid waste.

The Earth Moved provides an interesting glimpse at the minutiae that make up an earthworm’s existence. It also explores the bigger picture of earthworms’ impact on the environment around us, both in our gardens and in the larger landscape. If you read this book, you probably will never look at your garden soil the same way again.



Reviewed by Andrea Kingston, RCGC library volunteer, June 2012.