An earthworm needs moist, loose soil mixed with scraps of decaying vegetation. When the ground freezes hard, he avoids disaster by tunneling deeper, sometimes six feet below the surface. There he nestles in his burrow until things upstairs improve. Very often he is joined by another worm. The two of them twine together while reposing in a deep sleep, somewhat like hibernation. Earthworms also take such rest periods during hot, dry periods of drought.
Nowadays, we need tons of earthworms to help us build up our neglected soils. Many young ecologists have worm farms in their backyards to help solve this problem. Naturally, they want to know how to keep their little geniuses healthy and happy. When everything suits them, earthworms multiply at a great rate. Their market price is about one cent apiece and ecology minded farmers and gardeners buy them by the thousands.