Worms are invaluable aerators of garden soil. They turn organic matter into rich compost and help break up soil that would otherwise become too compacted to support healthy plants. There are even some worms that attack garden pests underground, thus eliminating a problem before it ever becomes visible. Buy some specialized worms and dump them in the garden. Or enrich the soil, forego pesticides, start planting and the worms will find you. Whether you import your worms or encourage the native earthworms to proliferate, they will soon be hard at work improving the soil and the health of the garden.
Red Wigglers - Worms known as red wigglers are the favorite of vermiculturists who dump a pound or two of the small active worms in the compost bin right along with the coffee grounds. Each worm can consume about a half pound of compostable food waste a day. Red wigglers like the warm surface areas of soil so they are also referred to as litter dwellers and may be called compost worms or manure worms. They will produce rich, abundant worm poop when they are allowed to munch away in the top few inches of soil or in a well-stocked compost bin in the dark. Get a supply of them from a reputable dealer and ask for red wigglers, Eisenia fetida, to get the right worms.
Red Worms - Red worms are a different manure worm, similar to their cousin, the red wiggler. They are smaller and lighter in color but are as voracious as the larger worms and will eat anything organic they can find as well as other substances that contain some organic matter. They are not as widely sold for compost bins but are cultivated for commercial use.
European Night Crawlers - European Night Crawlers are tunneling worms. They like to hang out as deep as ten feet below the surface burrowing through extensive tunnel systems. Their digging aerates the soil, even when it is tightly compacted and their castings enrich the soil at the same time so they are invaluable contributors to the garden. Night crawlers aren't good for compost bins because the material in the bins heats up and they don't like warmer temperatures. They also need to tunnel, but worm bins aren't deep enough to accommodate their incessant digging.
Nematodes - Nematodes have a bad reputation that is fairly earned. However, there is a type of nematode that is actually good for the plants and the garden. Roundworms, predatory entomopathogenic nematodes, live in lawns and garden soil and eat microorganisms. According to the University of Georgia Center for Urban Ecology, the roundworms that are helpful prey on insects who destroy plants, injecting them with a horrible roundworm bacteria that turns the insects to mush. Then, the roundworms eat them. This type of nematode is specially packaged and sold and must be released in the garden annually.