Rearing Earthworms

Ohio State University

By William F. Lyon

Earthworms are used by fishermen more than any other bait. They are the top choice for fish bait and will catch just about anything from bass and walleyes to channel catfish and bluegills. Unfortunately, earthworms are plentiful only in the spring and late autumn when the soil is moist. Rather than pay high prices for earthworms during the off-season, it is possible to collect and store nightcrawlers for the future or raise red worms.

Kinds of Earthworms

Fishermen favor native nightcrawlers because of their large size, which is up to 8 to 10 inches long. Garden worms are found in damp soils and are about 5 to 7 inches long. Manure worms are found in manure-rich soils and are about 4 to 5 inches long. Red worms are about 3 to 4 inches long and the easiest to raise, representing 80 to 90 percent of the commercial market.

Obtaining Earthworms

Nightcrawlers can be collected by flashlight after dark, following a steady, warm spring rain. Look for them near lawn edges. Cover the flashlight lens with plastic red cellophane to reduce light and keep worms from fleeing. Garden worms can be dug from moist soil under boards and stones, whereas manure worms can be dug from manure piles or manure-rich soils. Red worms can be obtained from a reputable worm dealer, usually advertised in gardening and fishing magazines.

Cages

Use wooden boxes, washtubs, steel drums cut lengthwise or other tight containers. Wooden containers 60 x 36 x 18 inches or metal tubs 2 feet in diameter and 12 inches deep are used as rearing boxes. Wooden containers should be well tarred on the outside and coated with hot paraffin wax inside. Metal containers should be coated inside with hot tar or two coats of good house paint.

Cage Preparation

Good loam or other porous soils containing organic matter work well. Organic matter (rotted or dead vegetation) may be added and mixed one part to three to four parts of soil if needed. Avoid using sandy or heavy clay soils. Fill the container to a depth of 8 to 10 inches with the soil used. Moisten soil throughout, but do not soak. Add food (1 pound of 15 percent protein mash such as hog or broiler mash mixed with 1/2 pound of lard or cheap vegetable shortening) within the top 3 inches of soil. Cornmeal can be substituted for the mash in the mixture if desired. This amount of food provides one feeding ration for the rearing containers described.

Biology

Commercial hybrid red worms are best for rearing. A culture can be started by adding 100 worms and covering with a damp sack to prevent evaporation. Earthworms must mate to reproduce, even though one earthworm contains both male and female reproductive organs. Eggs are formed in a slime tube that slips over the worm's head and forms a cocoon or capsule that incubates them. Eggs develop into tiny worms in the cocoon and crawl out through one end when ready to emerge. Cocoons vary in size and shape and are about 1/25 to 1/3 inch long. Some fast-maturing worms mature three to four months after hatching and will start their breeding cycle. Eggs are laid on top of the ground at one-month intervals, with each egg capsule containing 5 to 15 baby worms. If starting with two breeder beds, the crop will be ready for harvesting in about five months and continuing thereafter with proper care. Nightcrawlers are difficult to impossible to raise in homemade containers. Most resort to picking these worms from lawns, gardens and orchards for storing and future use. Worms live 10 to 15 years.

Feeding

Worms must be fed periodically to maintain production. Feed is added at the rate of one pound for each cubic foot of rearing space per month. Feeding once or twice each week is sufficient as uneaten food will contaminate the bed. Wetting the soil whenever food is added usually provides sufficient moisture.

Other Factors

The rearing container must be in a cool, protected place with the temperature about 60°F. A good place for the worms is a house basement. Maintain cultures at 60 to 65°F during the coldest weather by covering with a cardboard box. Be sure to have a thermometer. Heat may be provided by stringing a light bulb inside the cover, carefully avoiding any fire hazard. One finds young worms five to six weeks after "planting."

Provide good drainage with small holes covered with fine wire screen. Keep soil moist but not wet by spraying with water.

Worms can be harvested by emptying the box and sorting out those of suitable size. Some remove worms from the soil by transferring to a 10-quart bucket and allowing to stand for 30 minutes. Put top soil back in the tub and most worms will be found in the bucket bottom. The loam can be saved and transferred to a fresh box as egg capsules are present to start a new colony. Unused worms can be used as breeders.

Before sale or use, worms should be placed in sphagnum moss to "scour" for three to four days. Worms will become almost transparent but tough and lively. Haul worms to the lake in a moist bait box with damp sphagnum moss or in cans, cups, etc., that sit in the cooler with soft drinks. Keep worms cool and out of the hot sun.