What are Earthworms?

  • mini‐rototillers. They move through the soil, breaking up compacted soil so air and water can circulate more freely. Healthy organic soil may have enough earthworms to move forty tons of soil per acre every year.
  • nature’s recyclers. They voraciously consume decaying leaves, grassclippings, and kitchen scraps. As the material goes through their bodies, itchanges from waste to fertilizer. A worm will eat the equivalent of its weight each day. As they produce 2,000 to 3,000 offspring each year, they can consume a great deal of waste product.
  • producers of nature’s fertilizer. As the food processes through their bodies, they expel what is called “castings” which are very rich in nutrients and minerals.
  • truly a farmer or gardener's best friends.

Where do they come from?

Worms are present in all soil that has sufficient organic matter. A healthy soil should have at least ten earthworms in every square foot. Earthworms play an important role in the soil ecosystem. They are an essential part of healthy fertile soil. They are able to take organic material such as vegetable food waste, leaves, grass clipping etc. and produce organic humus in the form of castings. These castings have five times the nitrogen, six times the phosphorus, and ten times the potassium of most potting soils you would buy at a garden center.


Earthworms increase the water absorption in soil:  Heavy silt and clay soils cause water to run off before it can be absorbed. The need to conserve water and help it reach into the root zone of the soil is very important. Increasing organic matter and the worm population in soil makes it more receptive to water infiltration. Through a research project, the USDA found that a silt loam soil without worms had an absorption rate of .2 inches of rainfall per minute. The same soil, after hosting earthworms for only a month, increased water infiltration by 350% to .9 inches per minute. Earthworms provide tunnels and openings to the surface and their castings help to keep the soil loose and able to accept and retain water. Cultivated soil with little organic matter and few or no earthworms will lose its water stability after a few rains or irrigations.

Starting your worm farm: Worm farms can be started in five to thirty gallon containers or in a layered compost pile in the yard. A bin can be easily made out of cinder blocks. Form a “U” or square shape, two or three feet high. Start with a small area. Make this your “worm compost” area. Pile up plant clippings, grass clippings (except Bermuda grass), and all kitchen waste that originated from a plant. When the debris reaches four or five inches, throw on a thin layer of soil. This is important because soil contains many small organisms that contribute to the acceleration of the decaying process.

The compost pile should be about two feet or higher to heat up properly. If there isn’t a large quantity of debris, reduce the diameter. If the material is chopped or shredded, the decaying process will be accelerated. It is good to have a mixture of brown (carbohydrates) to green (nitrogen). A ratio such as 25:1 or 35:1(brown to green).

Will earthworms sting or bite? They don’t have stingers, stinging hair, or a hard outer protective skin. They can’t jump or fly. If caught by a predator, earthworms will detach portions of their posterior, or wiggle violently, or give off fluids from their dorsal pores. Their main protection comes from spending much of their lives in the soil, only coming out in the dark or when flooded.


The life of the earthworm: Earthworms are sexually mature in 60 to 90 days and can produce egg capsules every seven to ten days. The eggs hatch in 21 to 28 days. Each capsule produces two to twenty baby worms. Worms are hermaphrodites so they can all produce eggs. They reproduce by slipping their heads under the band or collar of another worm. They like to breed and settle in the center of the container where the temperature and moisture are the most constant. Under ideal conditions, one thousand worms can produce one million in a single year.

Harvesting worm compost: After three to six months, begin to harvest compost and add new bedding materials. There are two simple ways to accomplish this: the first is to place the bin under a bright light, (not direct sum as it will heat the compost and the worms). Worms do not like bright light. They will more further down into the container as compost is removed. Worms or eggs that are found can be placed back into the bin. The second way is to move all the compost to one side of the bin and add new bedding material and food waste to the empty side. In several days, the worms will move to the side with the new bedding and food, making the harvest of the compost very easy.

Using worm compost: Worm compost is rich in nitrogen, phosphorus, and many other nutrients and minerals important to healthy plant growth. It can be added as a mulch layer over the potting soil of houseplants allowing the nutrients to leach into the root area of the pots with each watering. It can be used as or mixed with potting soil. The nutrient-rich amendment can also be used in the garden with no worry of burning roots or over fertilizing as with chemical fertilizers.

What to do with the extra worm crop: The worm population will need to be thinned from time to time so they will not over‐produce for the size of container. Harvest as needed and put the extra worms in the garden or other compost bins, or give them to friends and neighbors. When planting extra worms in the garden, place about 200 worms in a 12‐ in. x 12‐in. hole with worm bedding. Space the holes 10 feet apart. Keep the area moist, but not flooded. A good worm population can run from 300,000 (7/sq.ft.) to 2,000,000 (45/sq. ft.) per ac. Some soils produce yields as high as 6,000,000 (140/sq. ft.).

To speed the process, use steer manure or other organic fertilizer and water well. Do not forget to water often enough to keep the pile damp, but not wet or soggy. In cooler weather, covering the pile with plastic for a week or so will build heat and speed the decaying process.

  1. Oxygen is an important part of the process. Turn the pile with a garden fork every week or two to provide oxygen and keep things stirred. If a compost pile doesn’t have sufficient oxygen, it will begin to smell, so the more it’s turned, the faster the organic matter will turn into compost.
  2. When the material is well into the decaying process, there will be earthworms in the compost pile. IMPORTANT: Once earthworms are in the compost, it is IMPERATIVE to keep the pile moist. Worms do not have lungs. They breathe through their “skin”. If it dries out, the worm cannot breathe and will die. Too much moisture will drown the worm.

IMPORTANT: Once earthworms are in the compost, it is IMPERATIVE to keep the pile moist. Worms do not have lungs. They breathe through their “skin”. If it dries out, the worm cannot breathe and will die. Too much moisture will drown the worm.

For the complete article use the link below to download the PDF version of this special report.

Robinson, M. L., and Rider, M. 2000, Starting A Worm Farm, Extension, University of Nevada Reno, SP-00-26

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Also of Interest:

Soil Properties, Part 2 of 3: Biological Characteristics
Since the introduction of synthetic fertilizers during the industrial revolution, most of the research has been focused on maintaining the nutrient balance in the soil. However, more researchers and agricultural producers are realizing that not only are the nutrients in the soil ...
Foster, S., McCuin, G., Schultz, B., Neibling, H., and Shewmaker, G. 2012, University of Nevada Cooperative Extension

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