What About the Workers? – Earthworm Versus the Redworm
In reality all these worms are technically species of earthworm and have much in common physiologically. However common usage assigns the name of earthworm to the deep burrowing garden worms that inhabit the soil around the roots of plants, whilst reserving the name of compost or manure worms to the varieties that are found in dung heaps, fallen leaves or other plant trash, right at the surface.
- Improved Soil Fertility Through Worm Activity
- The Common Earthworm
- Our Hero, The Red Worm
- The Role of Microbes in Vermiculture
- Suitable Varieties of Composting Worms for Vermiculture
- Latin Names for Worm Species
- Mix and Match Your Worms
Common Earthworms – lumbricus terrestris
Improved Soil Fertility Through Worm Activity
The world would be a sad, dirtier and hungrier place were it not for the humble garden earthworm and his/her* useful cousins known collectively as compost or manure worms. The red manure worms (technically known as epigeic or detritivorous earthworms) are actually the main heroes of this web site – but homage must first be paid to the basic hard working garden earthworm, for Charles Darwin, the famous 19th century evolutionist, who wrote Origin of the Species, said of them : –
“It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organised creatures.”
*Although his/her seems very PC – the real point is that all these worms are hermaphrodites, having both male and female sex organs.
The Common Earthworm
Actually several worm varieties have always been busily hard at work, striving to promote soil fertility – and this was long before a certain species of naked ape left the trees and turned his attention towards the invention of the plough. Common earthworms such as lumbricus terrestris, are probably the most efficient biological agents to be found anywhere in the world. They specialise in removing dead organic material from the surface of the land, greatly enriching it in the process, and then the clever earthworms carry the improved residue deep underground, right down amongst the roots of plants, where it is most needed. The hard working earthworms aerate and loosen heavy soils, improve water retention and simultaneously enrich the soil’s fertility with their faeces, which we call worm castings.
Our Hero – The Red Worm
However, our own particular heroes – the more aggressive red manure worms, always remain near the surface , where they are to be found partying in heaps of animal dung, or wriggling around in layers of decaying leaf mould and other interesting plant detritus. Because they live at the surface they are “epigeic” (gk = above the earth) and as they eat plant detritus, they are “detritivorous”.
VERY ACTIVE COLONY OF EISENIA FOETIDAE
These highly active red worm colonies speed up the entire natural composting process, by many months, by literally chewing through heaps of dead organic material, whilst continually beneficiating the fertility of the resultant humus with the richness of their castings, which are eventually utilized enthusiastically by plants. Worm castings are an extremely good plant food as they are always rich in nutriments, minerals, beneficial microbes, enzymes and plant hormones. Beneficial microbes associated with vermicasts have been scientifically shown to directly reduce bacteriological pathogens in soils upon which the worm compost is spread.
The Role of Microbes in Vermiculture
The relationship between earthworms (including the various composting worms) and the aerobic microbes or bacteria that accompany them is one of nature’s most perfect examples of symbiosis. The worms have millions of beneficial bacteria associated with them, both externally, on their skin, in the mucus secretions that keep them moist and also swarming internally inside their gut.
Worms have no teeth, bills or jaws, nor a true stomach and rely on the bacteria swarming around them to actually break down the foodstuff that we put in our bins. The deconstituted foodstuff is altered considerably, such that it can be sucked up by the worms as a slimy paste-like substance. It goes directly into their gizzard and passed onward through a very rudimentary digestive tract, together with the masses of bacteria that are swarming within the slime.
Inside the worm’s gut the breakdown process continues and the worms’ digestive tract, provides a perfect environment for the ingested bacteria, who multiply further and continue to convert the complex cell structure of the original foodstuff into its basic elements and compounds, altering it into a simpler form that can be used directly by both the worms and the bacteria for nourishment. These simple elements and compounds provide the basic building blocks to sustain both worms and bacteria and are reconstituted according to the messages carried by the DNA to build up the complex cell structures that create the living physiology of both worm and bacterium. A true win / win situation for both organisms.
Large numbers of these bacteria are released back into the worm bin, together with the waste products in the faeces or castings – our vermicompost. The microbes will have multiplied in the ideal environment of the worm’s gut and now, greatly increased in numbers, are once again ready to attack new food sources and start the process all over.
Of great importance, these waste products, or vermicompost, excreted by the worms have been thoroughly processed by the microbes and are now in the form of simple elements and compounds, that are readily taken up by our garden plants, providing a highly nutritious food for them. Moreover any dangerous toxins and infected material would have been simultaneously neutralised by the bacteria within the worms gut, as complex forms of pathogenic material are also broken down into simpler, more basic (harmless) components by the microbes. In the soil the process continues and worm compost, with its load of beneficial bacteria will also tend to improve the health of soil around the roots of plants by removing pathogens. This is the beauty of using worms and their huge army of tiny microscopic helpers, for your composting.
Suitable Varieties of Composting Worms for Vermiculture
For the worm farmer, wanting to set up worm composting bins, the red manure worms are a far better bet than the more stolid greyish-brown earthworms. The lively reds, reproduce far more quickly and are much easier to manage, because their habitat is epigeic i.e. at the interface with the surface. Unfortunately the common names of the different species of composting worms are confused by loose terminology and sometimes different worms are called by the same name. Unless the scientific (latin) name is also used, there is likely to be some confusion. The most common manure worm used in worm farming in the US is the red worm, (Eisenia foetida or fetida), alias redworm, red wiggler, red wriggler, brandling worm and often confused with the similar looking tiger worms (Eisenia Andrei). In the UK the larger nightcrawlers (dendrobeana) are much favoured for worm farming, especially for fishing worms. A species of European worm, the driftworm, also known as Red wriggler (Lumbricus rubellus) is also commonly used in vermiculture, especially for fishing bait as it is large, lively, robust and is even suitable for salt water fishing.
Latin Names for Worm Species
Because there are so many overlapping common names in use, such as red worm, redworm, red wiggler, red wriggler – the safest way to know you have the right worms is to use the scientific (Latin) name to identify the species.
Usually called the Tiger Worm, because of alternate bands of darker and lighter red colour. Often confused with Eisenia Fetida (Foetida) and to make things worse they are also known as Red Worms. Like Fetidae They are quick breeders and productive in vermicomposting and good fishing worms. They are between 2 to 3 inches long and weigh in at 900 to 1000 worms per pound. They are found throughout the world and as such are no threat to the environment if they escape. Temp range – Extremes: 38ºF-88ºF/Optimum 70ºF -80ºF
Eisenia fetida (foetida):
Commonest compost worm used in worm farming and easy to obtain. Usually called Red Wigglers, but also known as Red Worms, Red Wrigglers, Compost Worms, Manure Worms and Brandling Worms.
RED WIGGLER: EISENIA FOETIDAE
They got their name of red wiggler because as fishing worms as they are active on the hook and stay alive in water for some time, although they are a bit small for this purpose. They are between 2 to 3 inches long and weigh in at 900 to 1000 worms per pound. They are quick breeders and productive in vermicomposting. They are found throughout the world and as such are no threat to the environment if they escape. Temp range – Extremes: 38ºF-88ºF / Optimum 70ºF -80ºF.
Common name: European Nightcrawler also commonly called Redworm, it is much bigger than Eisenia Fetida (foetida). It is a quick breeder and a good composter (makes plenty of castings). Much sought after for fishing bait, as it can tolerate near freezing water and is one of the few “earthworms” suitable for salt water fishing. These worms can grow up to 7 inches in length, but usually are between 3 to 4 inches. 300 to 400 worms per pound.
Common name: African Nightcrawlers. These worms are much larger than Eisenia Fetida (Red Wigglers) and are commonly over six inches long. Good compost worms and great for fishing, because of their size and as they are lively on the hook and have a firm skin. They prefer temperatures of around 75ºF- 85ºF , but can tolerate 45ºF- 90ºF, cannot tolerate extreme cold and dislike disruption of environment and handling. Weight: 175 to 200 worms per pound.
A species of European worm, the driftworm, also known as Red wriggler. It is actually an burrowing earthworm and not a true compost worm, but in nature is Endogeic and feeds close to the surface. It is a large worm of average length 4 inches and is commonly used in vermiculture, as it is very productive at cooler temperatures. The optimum temperature is around 50ºF and it only stops breeding around 40º. Rubellus is also attractive as a bait worm as it is large, lively, robust and is even suitable for salt water fishing. However there is real concern that Lumbricus rubellus, as an exotic, could become a problem invasive species in North America and there are claims that it is spreading into the northern woods and causing damage to native forests. This is because it tolerates lower temperatures and wetter conditions than most compost worms. It causes damage by breaking down the plant subterranean trash that protects the surface roots of trees. Because it can burrow deeply, it can overwinter when the surface becomes frozen, unlike most compost worms such as Eisenia fetida. So before you start your worm composting – it is important that you check local requirements and choose the right worms for your area and never throw unused bait into the forest.
Common earthworm species, sometimes called nightcrawlers . They are not suitable for vermiculture as they are a deep burrowing species (Anecic). Their burrows, are semi permanent and may extend to six feet below the surface – these burrows are lined with mucus and help aerate the soil and improve water retention.
Common name : Indian blue worm. This species has a distinctive iridescent blue sheen to its skin. It is a tropical worm and does not tolerate cold or much handling or environmental disruption. Although small, it is suitable for vermiculture as it is a prolific breeder and matures quickly. It has one major drawback though – it is known for staging mass escapes from the worm farm, for no apparent reason and is somewhat unpopular for this reason. Temperature range – Extremes: 45ºF – 90ºF / Optimum 70ºF – 80ºF.
Mix and Match Your Worms ?
Many worm farmers prefer using a mix of Eisena fetida or foetida together with Eisena Andrei . Some composters claim that yields are increased further by adding the European Red Wriggler, Lumbricus rubellus to the menagerie. Each species has different requirements as far as temperature preference and growing conditions and would produce better or worse in different situations – hence the advantage of setting up cocktails of different species. Fortunately hybridization does not seem to be a problem.
However there is some concern that the large red European Lumbricus rubellus is an invasive species in North America and there are claims that it is spreading into the woods and damaging the native forest. So before you start your worm composting – it is important that you check local requirements and choose the right worms for your area. Just remember, even if you try to separate live worms from the worm castings, you will inevitably have some egg casings left in the vermicompost that you spread on your garden.