Earthworms are useful for fishing, gardens and compost bins. You can purchase worms at fishing stores, but it is much easier and cheaper to simply harvest them yourself. Instead of breaking your back by digging up your entire yard, encourage the earthworms to come out of the ground by taking advantage of their natural instincts. In no time, you will have more worms surfacing than you know what to do with.
Work in the evening or at night. Earthworms are less likely to come out in the daytime, especially in sunny areas, because they are vulnerable to drying out.
Soak the ground with a garden hose or sprinkler. Some experts believe earthworms come out of the ground to mate when it rains, according to an article about earthworms on the Nature North website. Saturate the ground thoroughly to begin encouraging the worms to head for the surface.
Plunge a pitchfork into the ground deep enough that it can stand on its own.
Hit the pitchfork handle with a stick to cause the handle to vibrate. The vibrations attract the earthworms, encouraging them to come to the surface. This technique is similar to a method used by worm hunters called "grunting."