Background Research

Introduction
Vermiculture is the process of raising worms in a controlled environment in order to produce castings. Worm castings are what is left behind after worms have taken the nutrients they need out of the scraps that you have fed them. Vericulture is also called worm farming. Vermiculture provides a cheap source of natural fertilizer, while it also gets rid of leftover scraps of food. Commercial worm farmers sell the castings to gardeners to make money. Commercial businesses do worm farming, and private citizens also raise worms. Worm farming is done all around the world in many different countries, including India, the United States, China, Australia, Argentina, and Canada.

Lately, people have been paying more and more attention to organic vs non-organic foods. With the increase in interest about organic foods, people are creating quantities of both organic and non-organic table scraps. The results of this project will help people know if they are feeding the worms the right things to produce the most castings possible.

Body
Research has started to show that food plants that are grown with organic fertilizers are better for humans and Earth than plants grown with chemical fertilizers. For example,the following statement is from an article published by a company promoting the use of organic fertilizers:

"Most experts agree that plants require a host of trace elements for optimum growth, but most chemical fertilizers do not include specific trace elements. Organic fertilizers provide a constant flow of amino acids and fatty acids where necessary."

Also it appears that non-chemical fertilizers are better for the soil than chemical fertilizers:

"Organic fertilizers continue to improve the soil condition while increasing crop/plant productivity. Most farmers will admit when asked if their soils seem to require more and more chemical fertilizers each year to achieve the same productivity. This common occurrence for farmers using chemical products is not the case for organic farmers; due to the improved soil condition each season, less fertilizer is used to achieve the same (or better) results" (http://www.deutrel.com/organic.html).

In another article published by Boston Gardens the point is made that that fertilizers made from living things are better for plants than non-organic fertilizers:

"Organic fertilizers are made from materials derived from living things. Animal manures, compost, bonemeal and blood meal are organic fertilizers. Chemical fertilizers are manufactured from nonliving materials. Rock phosphate for example, is a common source of phosphorus in chemical fertilizers. Inorganic fertilizers - Although they are immediately available to plants, inorganic fertilizers have three main disadvantages. They are subject to leaching, which occurs when the fertilizers are washed by rain or irrigation water down below the level of the plant roots. Nitrogen is particularly susceptible to leaching. As well, a heavy application of chemical fertilizers can "burn" seedlings and young plants. This is actually a process of drying out, or desiccation, due to the presence of chemical salts within the commercial fertilizers. A third problem associated with the use of commercial fertilizers is that overly heavy applications can build up toxic concentrations of salts in the soil and create chemical imbalances"

From Boston Gardens Website (http://www.bostongardens.com/bostongardens/detail.cfm?id=1186&catid=14&webid=1).

It seems logical that since organic fertilizers are better for plants, the Earth, and humans than chemical fertilizers, then waste from organically grown plants will be better food for worms than waste from chemicly grown plants.

Another aspect of casting production by earthworms involves pH balance. It appears that worms prefer to live in soil with a relatively low acid level. In an article published by Paul Backman on the Grounds website, he states:

"Many researchers have reported declines in earthworm populations directly related to declining soil pH (increasing acidity). Consistent with this is the fact that earthworms are scarce in soils with a pH of 5.0 or less, and plentiful between 6.5 and 7.0."

According to Mr. Backman, it also seems that when acid levels in the soil increase, it can affect how many castings worms can produce:

"It is possible that instead of population reduction, acidity merely shifts species composition to non-casting earthworms that are more tolerant of acid conditions."(http://grounds-mag.com/mag/grounds_maintenance_earthworm_casting_creates/)

In her book, Worms Eat My Garbage, Mary Appelhof believes that:

"Redworms can tolerate a fairly wide range of acidity in their environment, but slightly acid conditions are the best."

Based on the evidence that we have, it would logicly seem that if the pH balance in the soil is important to earthworms than the pH balance in their food would probably beimportant to them as well. In my project I will need to keep track of the pH balance in their food and in their bedding.

As part of my project I will need to measure the castings produced by my worms. In my research I did not find many ways to measure castings. In fact I found only one auctual description of a way to measure castings:

"To estimate annual casting production, let's assume that the worms are active only 150 days of the year, giving 102, 093pounds per acre per year, or over 51 tons of castings per year. Charles Darwin's approach in1881 to estimating castings production was to collect, dry, and weigh all the castings from a square yard of frass for a whole year. He recorded from three to 16 tons of dry earth annually ejected by worms in the form of castings." ( Mary Appelhof. Worms Eat My Garbage. Flower Press, 1997; Charles Darwin. The Formation of Vegetable Mould, through the Action of Worms, with Observations on their Habits. New York:D Appleton and Co, 1898, 1881.362p)

In the spirit of scientific discovery I will attempt to use Charles Darwin's method for measuring my worm's castings.

Conclusion
Since organic fertilizers are better for plants, the Earth, and humans than chemical fertilizers, waste from organically grown plants will be better food for worms than waste from chemically grown plants. Also, if the pH balance in the soil is important to earthworms, then the pH balance in their food will probably be important as well. It may turn out that waste from organically raised plants produces a more suitable pH environment for worms than waste from chemically fertilized plants.By observing these and other factors, and by using Darwin's method for measuring castings, my hypothesis is that organic food scraps will help worms produce more castings than will non-organic food scraps.