Soil Preference of the red worm, Eisenia fetida

by Amy Aerni and Sadie Ferguson


     Looking for Worms...                                                                                        Worms Found!                                                                             Massing Worms




Research Question

How will the masses of the composting red worm, Eisenia fetida, vary when they are placed in different soil mixtures over a period of five weeks?


The red worm Eisenia fetida will gain the most mass in the soil mixture consisting of potting soil and fruit matter because fruit contains a greater amount of calories when compared to the rest of the mixtures.


The fruit mixture will have the greatest change because fruit has the greatest number of calories compared to the rest of our mixtures. Here is a link that lists the calories of many of the fruits and vegetables we used in our experiment. Our vegetable mixture and leaf mixture boxes should have a less significant amount of growth compared to the fruit because these are also common composting materials that worms ingest, but they contain fewer calories. The newspaper box should have the second to least amount of growth because it is made mainly of fiber, which is not a usable calorie source for people or worms. Our control should have the least amount of growth since potting soil is not rich in nutrients compared to our other variable boxes. It is also possible that the worms in our control may perish because of lack of nutrients.

What did we accomplish?

We taught our class about the wonders of the earthworm, Eisenia fetida, and its composting preferences. By reading and understanding correlating research journals we gained much knowledge on this amazing worm and informed our class about what we learned. We involved the class when they helped us water the compost boxes and mass our worms. The environmental teaching group went on to teach young children about the benefits of composting and used our worms to make a compost pile in their classroom.


The purpose of this experiment is to study the growth of the red worm, Eisenia fetida, in a variety of different compost types (fruit matter, vegetable matter, newspaper shreds, and leaf litter). They will all be mixed with potting soil in an equal ratio. We will look to see which compost/soil mixture yields the most massive worms over a period of time inferring that increased mass equals a preference of the worm's soil type.

General Information

Eisenia fetida, commonly referred to as red worms, are earthworms that usually reside in the top ten inches of decomposing soil. They thrive in areas where they have access to leaf litter and organic matter. They turn this organic matter into fertile soil and are thus great composting worms.

How do worms work? Well, Eisenia fetida ingest the food particles through their mouth, digest it in their gizzard and absorb nutrients through their intestines for themselves and then excrete 'casts' or droppings that are rich in nutrients. These casts contain helpful bacteria that increase the cycling of nutrients into a form that plants can take up through their roots. Therefore as soon as the worms excrete the nutrients they are ready to be used immediately by the plants. Worms also help to speed along the process of humification, in which the organic portion of soil is created from the partial decomposition of plant or animal matter.

Worm History

Worms are not given a whole lot of recognition. When most people think about worms they do not think about them existing for millions of years or give them credit for the important decomposition they perform. The truth is that "worms have been around since 'long before the days of the dinosaurs' says Martyn Robinson, Naturalist with the Science Communication department of the Australian Museum. They appeared in at least the early Cambrian period, 570 million years ago or even earlier in the pre-Cambrian. It is even thought by some scientists that a species of flatworm was the world's first predator.

Fossils of worms are so far impossible to find because of the worms soft body that does not fossilize well. They do leave behind wormholes which fossilize. By looking at these wormholes we are able to determine their size and what type of habitat they lived in.

Worms have a variety of habitats ranging anywhere from the most inhospitable places on Earth like deep sea volcanic vents in the deepest darkest parts of the oceans and even on glaciers to nutrient rich habitats like rainforest floors. Worms are capable of surviving for long periods of time in arid environments without water by burrowing deep into the soil, covering themselves with a protective layer of mucus and hibernating.

Most of the worms in your garden are imported earthworms, which travel the world with humans as minute baby worms in the soil or orchard plants, and now thrive in the altered environment (Lennon, 2002).

Common Misconception about Earthworms

Chopping an earthworm in half does not create two worms! The end with the head will survive and grow a new tail but the tail end will die. There are, however, some aquatic annelids that fragment and both parts grow as new worms, a type of asexual reproduction (Lennon, 2002).


As the population of humans increase, the volume of waste increases as well. The corresponding landfills that the waste is deposited poison the surrounding area including ground water and soil. In an article by Margie Weitkamp called Background on Landfills and Use of This Exploration, it is pointed out that even when landfills are lined with plastic and monitored for waste spillage that runoff can still contaminate nearby groundwater sources (1997). This threatens not only the ecosystems around the landfills but also the living space that humans use.

Environmentalists are constantly devising plans to solve the landfill problem, but it persists and is growing out of control. Recycling is one way to cut down on landfill space but simply is not effective enough because of its high cost (Recycling, 2000). A cost-cutting solution that is not commonly utilized is composting. Recycling of wastes through vermitechnology (decomposition by worms) utilizes 'agro-waste' (Bhardwaj, Tripathi p. 275). By utilizing this organic waste, garbage sent to landfills is dramatically reduced and land space is saved. Landfills were created as a place to collect this trash until the space is filled and a new trash area is needed. By separating organic waste from man-made waste a large percentage of the garbage put in landfills can be eradicated.

The red worm Einsenia fetida is an ideal tool in breaking down organic matter. Here is an illustration of the digestive system of an Earthworm (Wormpost Northeast). They are often added to compost piles to increase the rate of decomposition (Farrell p. 76). Worms improve the condition of the soil as they search for food. They excrete castings, which contain five times the available nitrogen, seven times the available phosphorus and three times the exchangeable magnesium (Acosta, 2004). According to Bhardwaj and Triputni, 'earthworms should be considered keystone organisms in regulating the nutrient cycling processes in many ecosystems' (p. 275). The quality of the food that earthworms eat reflects their ability to create vermicasts, returning nutrients to the soil.

Worms are useful for their vermicomposting abilities on farms as well. They are added to treat 'livestock organic waste' which has become a problem because of the large amounts of cattle in one area. (Loh, Lee, Liang, Tan p.11) Not only are the worms used on livestock farms to break down wastes but they are also used to improve the soil. When a crop is harvested in the fall the barren ground is left behind. It is then tilled again in the spring by machines that break up the compacted soil. Eisenia fetida's castings would add an abundance of nutrients to the soil but they cannot survive in the hard-packed ground where crops such as corn and soybeans are grown. If all farmers had their own compost with the Eisenia fetida not only could the castings be added to increase the growth of their crops without harmful fertilizers but they could also use animal wastes as the compost material.

Another place composting occurs is in well-populated cities. Urban composting takes place in many different areas ranging from a bin in an apartment to large cities in New York and California. Composting is an ideal solution to garbage disposal costs. Some cities in California must reduce their landfill waste by fifty percent from 1994 to 2004 or face a 10,000-dollar fine. Many of these people turn to our little friends the Einsenia fetida to make their fruit peels and vegetable trimmings into nutrient rich soil. (Why Worms?)

As Aristotle once said "earthworms are the intestines of the earth." Without them, much of the world’s decomposers would be lost. The dead organisms that fell to the ground would take much longer to become soil again. Landfills would take up much more space than they already do. We need worms whether our world finds them appealing or not.


Research Design/ Materials and Methods

We used a scale, boxes, black garbage bags, watering can, worms, potting soil, organic fruit and vegetable waste, newspapers, and leaf litter. Our class will monitor the worms as well as keep them moist. The location that we chose to use is the room inside of Boyd right in front of the green house. This location was chosen because it maintains a constant temperature that is favorable to the worms. It also does not receive excessive amounts of sunlight, which would hinder the worms' vermicasting abilities. The twenty boxes were placed on the ground in the room off to the side so they were not in the way.

We purchased half a pound of worms. Since they exist at the surface of soil we did not need large volumes of soil and small cardboard boxes sufficed. We lined them with plastic to keep the worms from ingesting our containers, and poked small holes in the bags so there would not be any standing water. We lettered the soil types A through E. Their corresponding boxes were numbered A1, A2, A3 and so on. There were four boxes for each soil type. Four boxes contained only potting soil as a control. The rest of the mixtures were sectioned in four boxes; every four boxes had half vegetable matter, fruit matter, leaf litter, or newspaper shreds along with half of a potting soil mixture. Once we received the worms and set up our boxes filled with soil we let the contents settle for a few days.

We set everything up and placed ten worms in each box. We tried to distribute the sizes of the worms equally so that the masses would be as similar as possible in the beginning of the experiment. The red worms were washed off and massed every week as a group. We recorded our data for five weeks. Our class was involved in making sure the moisture levels of the boxes were maintained. They also helped us mass the worms during two of the weeks. The boxes were covered in order to keep in moisture and the worms. It was important to keep the soil moisture at 75% or more and the temperature between sixty to eighty degrees so the worms could be the most productive (Red worm (Eisenia fetida), 2004). A spray bottle was supplied along with a watering can. The worms were monitored and watered weekly. Greater moisture was proven to keep the worms the most active and healthy.

By massing the worms over time, we hoped to see a greater mass in the worms that had access to the best nutrients. We presumed the best nutrients to be in the fruit compost. The worms digested the potting soil control as well as the additive and grew to become larger and heavier. The red worms that gained the most weight should have been contained in the soil that they prefer. After five weeks passed, our data was analyzed to see if our hypothesis was correct.

Preliminary Data Chart

Figure 1. This is a comparison of the beginning weights of our red worms and their corresponding p-values.

Chart Information

This chart displays and compares the first masses taken of our worms. It is shown that the masses of the worms within the different boxes are not statistically similar. When we separated the worms for the different boxes we did not notice that the first worms we massed were smaller than the later worms. Since this happened, our first two boxes contained lighter worms and the last three contained heavier worms. After calculating the differences over time, we must remember that the beginning masses did not all have a similar starting point. Our results will have to rely on the average change in mass of each category of box over time.

Timeline/ Calendar

Week of 10/10: Prepared soil mixtures Monday 10/11. Week of 10/17: Rinsed and massed new worms, add them to prepared soil mixtures on Monday 10/18. Checked moisture on Tuesday 10/19. Checked moisture and watered boxes on Thursday 10/21. Week of 10/24: Took second mass of worms on Monday 10/25  Took pictures of setup and worm massing. Checked moisture on Tuesday 10/26.Checked moisture and watered boxes on Thursday 10/28. Week of 10/31: Took third mass of worms on Monday 11/1. Checked moisture on Tuesday 11/5. Week of 11/7: Took third mass of worms on Monday 11/8. Checked moisture on Thursday 11/11. Week of 11/14: Took fourth mass of worms on Monday 11/15. Checked moisture on Thursday 11/19. Week of 11/21: Took fifth mass of worms on Monday 11/22. Took pictures of baby worms. Week of 11/28: Clean up. Sent worms with Educational Group for children's composting.



Figures 1-5 show the average masses of each type of compost broken down by week. Our controls were the boxes that contained only non-fertilized potting soil. These masses of the worms did not significantly change throughout the five weeks.The boxes that contained vegetable matter mixed with potting soil averaged the heaviest worms after five weeks. Each type of compost contained worms that increased in mass from the first to last week except for our control.

                              Figure 1: Worm Weight in Fruit Compost Over Time

From looking at this graph the worms that were placed in the fruit compost had a definite increase in mass.  The average mass in the beginning of the experiment was around 0.16 grams and by the end of the experiment the average mass was about 0.28 grams.  When comparing the weights there was a steady increase of approximately 0.05 grams per week for the first four weeks.  During the final week of the experiment there was an insignificant increase in the average weight of the worms.  The P-value comparing the weights over the five weeks is 0.0001. This provides evidence that there was a significant change in the mass of the worms from time A to time E.  Therefore the null hypothesis, that the masses of the worms would remain the same, can be rejected. However, when comparing the last three average weights the P-values are 0.068 and 0.737, which fail to reject the null hypothesis. 

                                Figure 2: Worm Weight in Leaf Compost Over Time

This graph shows an increase in the masses of the worms for the first four weeks.  The overall P-value is 0.0001. There was an increase of approximately 0.04 grams in the average masses during the first week followed by slight increases during the next two weeks. The changes from time B to time D produced P-values higher then 0.05, thus these differences in weight did not reject the null hypothesis. In the last week there was a drop in mass of about 0.035 grams. This large drop in the last week brought the average mass back to the same weight as in Time B. This is the reason that when comparing Time B to E there is a high P-value of 0.94.

                            Figure 3:Worm Weight in Paper Compost Over Time

The graph above shows a large increase in the average weights of worms from time A to time C. It follows with a decrease in the weights from time C to time E. The P-value for all the weights over time was 0.0001. This was significant enough to reject our null hypothesis. Although there is a visible decrease in the last three average masses of the worms, the weights did not change enough to be considered statistically different. When comparing the last three average masses, we cannot reject our null hypothesis.                          

                        Figure 4: Worm Weight in Potting Soil Over Time

   The graph above does not show any significant change in average mass of the worms over the five weeks producing a P-value is 0.75.  It is never possible to compare any of the times and get a statistical difference.                          

                                Figure 5: Worm Weight in Vegetable Compost Over Time

The graph above shows an increase in average worm mass from time A to time D.  The P-value for the entire time period was 0.0001.  The last three changes in average worm masses are not statistically different with P-values of 0.086, 0.344, and 0.457.  So, when comparing these three times, the null hypothesis cannot be rejected.

Figure 6: Comparisons of Final Average Worm Masses

When looking at this graph the final averages of worm masses are shown.  The worms that were placed in the vegetable compost were by far the heaviest with average mass of about 0.35 grams.  The worms placed in the fruit compost were the next heaviest with an average mass of about 0.29 grams.  The remaining three compost groups, leaves, paper and potting soil, were all very similar with averages at around 0.21 grams.



Our results did not support our hypothesis that Eisenia fetida would gain the most mass in the fruit matter compost mix.  From viewing the graphs it was shown that in fact the vegetable matter produced the heaviest worms followed closely by the fruit matter mix.  More evidence that the worms preferred these two varieties was that baby worms and worm cocoons were found in decomposing grapefruit and decomposing carrots.  Possible reasons for these results were that although fruit contains more sugars and calories it has less fiber than vegetables.  The fiber may have been an element, which caused the worms placed in vegetable matter to do so well.  Another possible reason that the fruit matter worms were not the heaviest may be related to the fact that the fruit decomposed more quickly.  This meant that there was less food for the worms to eat over time.  The vegetables decomposed more slowly when compared to the fruit allowing for a slow release of nutrients throughout the whole experiment rather than a huge amount in the very beginning.  The fruit compost also attracted a large number of fruit flies.  While the fruit was abundant the flies were seen eating the decomposing matter leaving less for the worms to eat.

Figures 1-5 above show the statistical data of what happened to our worms over time.  Figure 1 shows the worms average masses in the fruit compost over 5 weeks.  If matter had been added every week the increase of the masses would have likely continued.  Because matter was only added twice during the 5 weeks the worms were not given enough nutrients to continue growth.  Figure 2 shows the worms average masses in the leaf compost. The leaves took longer to decompose which made them difficult for the worms to ingest.  This is why the weights stayed relatively low over time.  Figure 3 shows the worms average masses in the paper compost.  The paper compost did not offer sufficient nutrients for the growing worms.  The masses of these worms stayed very low during the whole experiment.  The B time section is missing from the data because of miscommunication between the experimenters. This error makes it look as though there was a large increase in mass during the first two times when really there is one time missing in-between.  Figure 4 shows the worms average masses in the potting soil.  The potting soil was used as a control so we did not expect the worms to gain a considerable mass.  Worm growth was not possible because the potting soil lacked any sort of nutrients for the worms.  Figure 5 shows the worms average masses in the vegetable compost.  Since the vegetables decomposed at a slow but steady rate the worms were able to receive sufficient nutrients and grow to the heaviest masses.  Figure 6 shows the final average masses of each compost type.  It is clear from this chart that the worms preferred the vegetable compost because the masses are by far the highest.

If we were to revise this experiment we would start off by distributing the worms equally by mass. Our preliminary data illustrates that the fruit and leaf boxes contained lighter worms at the beginning of our experiment. In an ideal situation, all of the weights of the worms would be equal. Our second revision would be to mass the amount of matter and soil added to each box. This way all the worms would have the same opportunity to find and ingest nutrients that would allow growth. Third, we would set up impermeable boundaries to keep the worms in their appropriate boxes. We found that many worms had migrated from dryer boxes to moister ones. We never found any worms in the process of migration, but missing worms were counted in nutrient rich and moist boxes. Fourth, we would follow stricter watering schedules. Worms were found fighting to stay alive and may have tolerated nutrient poor conditions if they were kept moist. Fifth, we would have used non-biodegradable boxes. By the end of the fourth week, a few boxes were found with soggy bottoms. If we used plastic containers, we would not have this problem and it would have kept the area cleaner for Harry, the greenhouse keeper. Finally, we should have added matter to our boxes every week. This way we would be sure of adequate nutrients for the worms. If we added nutrients every week and kept the boxes moist, we could find out just how large the worm, Eisenia fetida could become in ideal conditions.

After our experiment was over, John, Emily, and Gina's group used our worms to educate young children about the benefits of composting. They used the information we gave them in order to pass this knowledge to the youth of Tallawanda Elementary School. Even though only approximately thirty children were educated on the benefits of composting using earthworms they will pass this information on. Education is the answer and John, Gina, and Emily's efforts will help to solve the waste problems of today and tomorrow.

"Earthworms play a vital role in many soil ecosystems, but quantitative information on their feeding habits is scarce" (Jager et al. 2002). We were not able to find any experiments that attempted to answer the soil preference of earthworms, but our experiment successfully helped to answer many of these questions. Even though we were not able to find any professional journals dealing with the soil preference of earthworms, many citizens are involved with worms because of their composting abilities. Composting supporters are found all over the world. One article by Heather Rigney gives information on the positive uses of vermicasts in her garden (2001). Worm sites are easily accessible on the internet if the public is interested in starting their own worm gardens.

Why does this interest us?

Worm growth and soil preference are interesting to us because worms are underappreciated. They are the natural equivalent of fertilizers without the harmful side effects toward the environment. They not only benefit the soil but they provide a food source for many secondary consumers and the fish that we like to catch and eat.

We find this project interesting for several reasons. Sadie and I are taking some small slimy creatures that we call worms and transporting them into a foreign area. Then we just let them create nutrient rich soil and grow without any other help from us other than to keep the soil moist. It's amazing. By weighing the worms every week we hope that we can see which soil best suits them and hopefully in the process get to know how the Eisenia fetida really works.

Amy has recently taken up fishing with her dad out in Lake Erie. They used worms similar to the Eisenia fetida to catch their delicious perch. Worms are remarkable creatures and now we can be truly aware of all their special capabilities.

All of Sadie's life her parents have been gardening enthusiasts. They decided to start composting to use left over fruit and vegetable waste from the kitchen and to create nutritious fertilizer for the plants. Ever since the compost bin was constructed the whole family has been involved in adding leftovers. Even the dogs like to check it out every once in a while.

Literature Review

Campbell, N., & Reece, J. (2002). Biology. 6th ed. New York: Benjamin Cummings.

*It is important to understand the anatomy of the worms that we are studying. This is why we have chosen a descriptive illustration of the anatomy of a common earthworm. The Eisenia fetida is a species of earthworm and since we are measuring their composting abilities it is vital that we know how its digestive system functions.

Farrell, Molly. (1998). An urban adventure: Vermicomposting food residuals in two steps. BioCycle 39, 11.

*This article is relevant because it looks at the bigger picture of composting to help a large community in New York control its organic waste disposal. The resulting nutrient rich soil is then sold to the corresponding community. The article also talks about ideal conditions for the Eisenia fetida including temperature and light preferences.

Feeny, C. (1999). The worms crawl in, the worms crawl out. Environment, 41(3), 22.

*Composting saved the school in this article six thousand dollars per year in waste disposal cost. This information is useful because it highlights the benefits of composting, not only producing nutrient rich soil but saving a significant amount of dough in the process.

Gonzalez-Prieto, S. J, & Carballas, T. (1995). N biochemical diversity as a factor of soil diversity. Soil Biology Biochemistry, 27(2), 205-210.

*This article infers that worms and other soil-dwelling animals increase the chemical variation of soil. This makes the soil usable by a variety of nutrient dependant organisms. Worms are an important factor in producing this nutrient rich soil and are therefore vital to quality compost.

Grobe, K. (1999). Worming the way to finished compost. BioCycle, 34-35.

*Because large cities have little room for garbage disposal, composting is a useful tool to cut down on land fill space and it produces fertile soil in the process. The Eisenia fetida is the main factor that makes the organic matter into the fertile soil instead of useless landfill sludge.

Gunadi, B., Edards, C. A, & Blount C. (2002). The influence of different moisture levels on the growth, fecundity and survival of Eisenia fetida in cattle and pig manure solids. Soil Biology, 39, 19-24.
*Our red worms will be contained in an area that must keep them healthy and alive so we can measure their mass over time. Moisture levels must be kept at a specific percentage so the worms will be productive. This article pertains to how we will provide the worms with a suitable and moisturized habitat.

Jager, T., Fleuren R., Roelofs W., and de Groot, A. (2002). Feeding activity of the earthworm Eisenis andrei in artificial soil. Soil Biology Biochemistry, 35, 313-322.

*Although earthworms prefer being in nutrient rich areas like leaf litter or manure, they still need to consume the less rich mineral soil as a part of their daily diet. The soil we will place our worms in will not only contain the nutrient rich ingredients, but it will also be mixed with potting soil because the article claims regular soil is also an important part of the worm diet.

Kaushik, Priya and Garg, V.K. (2003). Dynamics of biological and chemical parameters during vermicomposting of solid textile mill sludge mixed with cow dung and agricultural residues. Bioresource Technology, 94, 203-209.

*This article shows how farmers who work with solid textile mill sludge can use vermicomposting as an alternate technology for the management of the sludge mixed with cow dung. It provides inside that we will be able to use as to the benefits of using worms for controlling pollutants.

Loh, T.C., Lee, Y.C., Liang, J.B., and Tan, D. (2003). Vermicomposting of cattle and goat manures by Eisenia foetida and their growth and reproduction performance. Bioresource Technology, 96, 111-114.

*This article is important for our experiment because of the descriptions of vermacast and its relation to compost and also because of the detail it provides in how to go about massing and taking care of the worms used in the study. Because we are not worm experts, any sort of information on worm care is beneficial to us.

Manna, M.C., Jha, S., Ghosh, P.K., and Acharya, C.L. (2002). Comparative efficacy of three epigeic earthworms under different deciduous forest litters decomposition. Bioresource Technology, 88, 197-206.

*This article talks about the benefits of earthworms in preventing forest fires. When earth worms are present in forests they will decompose the leaf litter making the forest floor less fire friendly. This adds another important reason as to why studying our Eisenia fetida is extremely important on multiple levels.

Paradise, Christopher J., (2001). A Standardized Soil Ecotoxicological Test Using Red Worms (Eisenia fetida). The American Biology Teacher, 63,662-668.

*Vermicasting is an extremely helpful tool in breaking down detritus, increasing the rate of soil formation and nutrient cycling, improving water infiltration rates, neutralizing soil pH, and stimulating microbial population. This article points out the ways in which worms are able to do all of these tasks as well as why our chosen specimen, Eisenia fetida, is an ideal test species for the job.
Rigney, Heather. (2001). Looking for Mr. Goodworm. Organic Gardening,48,48.

*Heather Rigney, a composting enthusiast, offers to us the point of view of a "regular" person using composting for her own benefit. Her article offers insight into how easy it is to cut down on
one's personal waste out put while creating a nutrient rich fertilizer for the garden.

Tripathi, G. and Bhardwaj, P. (2003). Comparative studies on biomass production, life cycles and composting efficiency of Eisenia fetida Savigny) and Lampito muritii (Kinberg). Bioresource Technology, 92, 275-283.

*This article was extremely informative! The study is close to our own test and it offers a large amount of background information on our worm of choice (Eisenia fetida) such as optimal living conditions (temperature, moisture levels, etc.) and the benefits of using earthworms to balance ecosystem problems.

Website References

Acosta, E. Biconet, (2004). Earthworms: Eisenia fetida. retrieved Oct 06, 2004, from Earthworms, Red worms, red wigglers etc. Web site:

*It is important to know how our Red worms will improve the condition of the soil. This website has a paragraph dedicated to exactly what Earthworms excrete that makes the soil so fertile.

Lennon, Troy, (2002). The World of Worms: the intestines of the Earth. retrieved Oct 19, 2004. Web site: takchall. Worms/tkcharc_worms_intor.html.

*This site helped us a lot on getting to know the history of the worm. It was very informative on topics such as when worms first appeared on Earth and varying habitats that they live in today.

Weikamp, M. (1997). Background on landfills and use of this exploration. retrieved Oct 06, 2004, from

*Landfills are the reason that many people are turning to worms to lessen their waste output. This site points out the downfalls of landfills and what can be done to improve them.

Recycling: can local authorities afford it? (2000). Retrieved Oct 06, 2004, from

*Recycling is expensive. The link to this site gives a clear-cut fact sheet on why Recycling is so expensive along with other pros and cons that come along with it.

Happy D Ranch, (2004). Red worm (Eisenia fetida). retrieved Oct 07, 2004, from Happy D Ranch Web site:

*Happy Ranch is an expert red worm user and supplier. The site gives tips on how to manage our own composting area and what to expect over time. If we are wondering what is going on with our worms we can probably find an explanation in the Happy D Ranch website.

VermiCo, (n.d.). Why worms?. retrieved Oct 06, 2004, from Why Is the Worm Industry Expanding? Web site:

*The 'Why worms?' website is posted by an environmentally friendly group called VermiCo. They support using compost to reduce wastes and are highly into utilizing worms for this reason. They also point out that red worms are wonderful fish bait.

Wormpost Northeast, (n.d.). Vermicomposting. retrieved Oct 06, 2004, from Worm Biology Web site:

*Wormpost Northeast has excellent diagrams of the digestive system of a common earthworm. It gives the difference of the Nightcrawler compared to the red worm that Sadie and I will be using. It is an overall informational guide to the Eisenia fetida.