The soil in a garden has many types of insects and worms that you don't see until you start digging. While many people cringe at the sight of these creatures, they are actually a sign that your garden is healthy. Worms in particular greatly benefit a garden by aerating the soil near plant roots and by providing natural fertiliser to the soil. There are several types of worm species found in a garden.
Insert a garden spade 5 to 6 inches into the soil of the garden and dig a hole. You should see one or two worms wriggling in the soil. If you do not see any worms, fill in the hole and choose another location.
Examine the colouring of the worm to see if it has a red tint. If so, then you have identified a red worm, also called a red wiggler. They thrive in areas of decomposed matter and probably were transferred to the garden via the addition of compost.
Pick up the worm with your fingers and watch it to see if it wiggles very quickly. If so, you have identified a manure worm, which is also called a bandling or an angleworm.
Wait until nightfall and point a flashlight at the surface of the garden to search for worms. If you spot worms on the surface, these are night crawlers. During the day, nightcrawlers dig 5 to 6 feet into the ground. You will only see them at night.
Look for any worms that are short and stubby, and have a white body. These worm are called grubs and are actually the larva of the Japanese beetle. They are harmful to plants, and you should treat the garden with grub killer to remove them.