Vermicomposting FAQ's

We start this new section with six popular questions about earthworms and vermicomposting. Visit us again often as this section will add new questions and answers periodically.

Click here to read updated questions on Worm Castings (updated 2-22-06).

1. What is meant by vermiculture, vermicomposting, and vermistabilization?
"Vermiculture" refers to the science of breeding and raising earthworms. Such methods provide a unique opportunity to recover large quantities of organic wastes, converting them, as in manufacturing, into valuable products for agriculture, forestry, horticulture, and pollution management. Though quite different from conventional thermophilic composting, these methods are commonly referred to as "vermicomposting."

In vermicomposting, earthworms obtain their nutrition from the microorganisms thriving on the decaying organic matter. As the worms multiply, they can consume more material. Their feeding also increases the surface area of the material being treated, thus increasing microbial growth. As this process continues, complex changes occur and eventually a finely structured material, known as worm castings or vermicompost, is produced. Worm castings are suitable as both a plant growth medium and an agricultural soil amendment.

"Vermistabilization" refers to the use of earthworms to stabilize (also condition or cure) organic materials that have been predigested through aerobic composting or other means. Again, the earthworms consume microbes and small particles of organic matter to produce worm castings.

2. So does an earthworm "hear," "see," or "smell"?
Yes and no. Like a snake, the earthworm uses its setae to sense vibrations and "hear." The body wall contains many nerve receptors that taste chemical changes (or "smell") and other nerve receptors that detect light changes (or "see") in their environment. One interesting fact is, earthworms can't "see" the color red. (Question and answer excerpted from The Worm Book.)

3. How much do redworms eat?
The feeding rate, also known as the loading rate, for vermicomposting systems is governed primarily by the amount of food that the population of worms can consume. Composting worms are capable of ingesting one-fourth to one-half of their body weight in wastes each day [Haimi and Huhta, 1986]. Other researchers claim worms can consume one to two times their body weight per day. The varying rates may be attributable to variations in temperature, pH, or other environmental conditions. Experience from existing projects suggests that for planning purposes, a loading rate of 0.25 to 0.5 lb. (or kg.) feedstock per 1.0 lb. (or kg.) of worm biomass per day should be adequate for the low and high feeding potential.

Thus, the estimated total weight of the worm population in a vermicomposting system will be used to determine the loading rate. This relationship is often referred to as worm density (the average weight of worms per some measure of area or volume). Worm population samples are used to estimate worm density throughout the entire system. Because worm populations can grow quite rapidly, maximum worm densities can be achieved quickly under optimum conditions.

4. How long will a wooden box last?
Used continuously, without ever letting the box dry out, unfinished wooden boxes should last about two to three years. Longevity can be increased by letting the box dry out for several days between set-ups. Some people prefer to rotate between two boxes for more convenient maintenance and to allow the boxes to dry. A good finish that seals all edges, such as polyurethane varnish, epoxy, or other waterproofing material, should extend box-life considerably. (Question and answer excerpted from Worms Eat My Garbage).

5. How many worms are there in a pound?
That's a bit like asking how many people are there in a ton? It depends? The size, influenced by age and diet, of the people or worms determines the number per ton or pound. Of course, we can talk of averages. One old, often used rule of thumb is that there are on average 1,000 redworms of various sizes and ages in a pound. Our experience is that the average may vary on either side by the hundreds.

6. How can gardeners increase the population of earthworms in their soil?
The best way to attract and nourish earthworms is to feed them lots of organic matter. Peel back a layer of mulch that has been in place for at least a few days, and you will see the evidence of their activities--little piles of castings next to their tunnel entrances-and the worms themselves, working on your behalf. (Answer excerpted from Start with the Soil).

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