EARTHWORMS
(Lumbricus & Helodrilus)

They are a pretty good food source for all sorts of reptiles including skinks, dragons and are a favourite for tortoises and axolotl's.

Nightcrawlers (Lumbricus terrestris) , which is up to 8 to 10 inches long.
Garden worms (Helodrilus caliginosus) are found in damp soils and are about 5 to 7 inches long.
Manure worms (Helodrilus foetidus) are found in manure-rich soils and are about 4 to 5 inches long.
Red worms (Lumbricus rubellus) are about 3 to 4 inches long and the easiest to culture. Commercial hybrid red worms are best for rearing.

1. Earthworms must mate to reproduce, even though one earthworm contains both male and female reproductive organs. 
2. Eggs are formed in a slime tube that slips over the worm's head and forms a cocoon or capsule that incubates them. 
3. Eggs develop into tiny worms in the cocoon and crawl out through one end when ready to emerge. 
4. Cocoons vary in size and shape and are about 1/25 to 1/3 inch long. 
5. Some fast-maturing worms mature three to four months after hatching and will start their breeding cycle. 
6. 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.

Temperature Range:

Maintain cultures at 60 to 65°F (15° - 18°C)

METHOD:

What you'll need:
wood to build a box
cheap hinges
fine plastic screen
outdoor rated paint
peat moss
bricks
good loam soil
corn meal

What you'll do:
Build a box out of wood (any size is fine, a bigger box = more worms) (apartment dwellers can make do with a 1' x 1' x 8" box)
Attach the top with two cheap hinges.
Drill/cut two 2-inch holes in the front of the box in such a way as to line up the bottom of the hole with the bottom of the inside of the box
Paint the box with any outdoor rated, oil based paint.
Place a small piece of fine plastic screen against holes that were drilled/cut. Make sure the screen is placed on the inside of the box. Firmly nail the screen into place. The screen will allow the box to drain, but will not allow the worms to escape.
Mix three parts peat moss with one part loam soil.
Fill the box with this mix (remember the peat moss will compact after it gets soaking wet).
Place the peat moss in the box and completely soak the peat moss (stir it up until it is uniformly wet).
Place one brick at each front corner and two bricks at each rear corner so that the box slopes forward and can drain from the holes.
Place a pan under the holes to catch the future runoff (unless the box is placed outside).

A culture can be started by adding 100 worms and covering with a damp sack to prevent evaporation.

Every three or four days, sprinkle a light layer of corn meal on top of the peat moss. Note: before each new layer is applied, use a small, tined garden hand tool to stir up the peat moss and to mix the corn meal left over from the previous feeding into the peat moss.

After about a month, there will be literally millions of worms ranging in size from tiny little young worms to fully adult worms.

To feed:

Earthworms can survive for several days submerged in water in your refrigerator, which allows most of the soil in their gut to pass through their system, so that you won't dirty your tanks as much. 

I usually stick earthworms under very hot tap water to kill them humanely prior to chopping them up with a razor blade (or cutting large ones apart with surgical scissors) to feed them to smaller fish, like killifish. It is important not to overfeed!

Housekeeping:

Worms must be fed periodically to maintain production. 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.