Eisenia fetida commonly called the red wiggler worm versus Eisenia hortensis which is know as the european red worm or the night crawler. Both worms can be used as a composting worm but what are the differences and which one will work the best in a given scenario.
Ok, so the title of this post could use to be a little shorter, but the topic here is to discuss the two different worms and compare them to each other. The Eisenia fetida is the scientific name for the most common composting worm that is known best as the red wiggler worm. Often times it is called by other names such as; composting worm, red worm, manure worm, tiger worm, trout worm and they are other names as well. The second most common worm is Eisenia hortensis. It goes by a number of names as well and is even more confusing because of the fact that it is often called a nightcrawler when in fact it is not. It is a composting worm and does not live in the dirt as a nightcrawler would. With out going on a tangent here, it is important to note that composting worms do not live in dirt, they live in organic material. Here is a post on the living substrates of worms. E hortensis is commonly called European red worm, european nightcrawler, dutch worm, super worm, and confusingly enough it is commonly sold as a red wiggler. The problem with people selling E hortensis as red wigglers is, when someone buys the real red wiggler expecting to get what they had been sold as such but was actually E hortensis, they see the worms and they are much smaller then what they were used to.
Eisenia fetida makes an excellent composting worm for many reasons. It is a fast multiplier and can lay an egg capsule every week under good conditions. Each egg capsule can contain up to 5-6 worms but 3 or so is common. It takes about 90-120 days for the young worms to reach maturity after hatching. Hatching can take anywhere from 21 days to never. The eggs can go into a hibernation state and wait on proper conditions before hatching. This is very helpful to the worm farmer. If something should happen to a worm bin and a farmer was to loose many or all of his worms, it would only be a matter of time until the beds would be repopulated with more red worms. Not only is the red wiggler a fast multiplier but it also can tolerate a wide variety of conditions. This is important because some times worms bins can get very hot and then nearly freeze at other times. Also this worm can tolerate a wide pH. The pH in a worm bin can change a lot as organic matter decomposes. Further more they can tolerate a different moisture levels. I have seen E fetida in bins that were soaking wet and I have seen them in nearly dry bins. They seem to be fine in either although they do best in when the moisture levels are somewhere in the middle.
Eisenia fetida worms feed on the top of the bin and move up through the food. This helps make feeding the worms easy and allows for easy separation of worms and the castings. This can create problems though if feed gets mixed into the bedding the red wiggler will not eat it and the food may sour. Souring food in the worm bedding can lead to problems. This is why I always emphasis not mixing feed into the bedding. It is ok to bury food a couple inches deep under the bedding, just don’t mix or stir bedding if there is food in it.
Eisenia fetida likes to stay put and not to run out of the beds. Many other species of worms will leave your nice prepared and safe home that is well fed just to spite you. It is true that under some conditions even this mild mannered worm will crawl away, but usually there is something wrong which is causing this.
It is easy to see why the common red wiggler is so widely used and has become the number one composting worm. This in itself is an advantage for this worm, as much has been written about it and information is easy to find. However the european nightcrawler has some merit as a composting worm as well. In the next post I will describe the good and bad of Eisenia hortensis.