During the past year or so (especially the last 6 months) I’ve had the opportunity to spend a lot more time working with European Nightcrawlers (Eisenia hortensis / Dendrobaena veneta), and as you can probably tell from my writings, I’ve really come to respect them a lot more.
It’s funny to think that my frustrating experience with Euros in my VB48 actually helped lead me down the path to my new found appreciation of these worms. I guess you could say it’s one of those “making lemonade out of lemons” situations that actually panned out (as you may recall, I came up with a skirt-tray system down below the VB48 that’s been working very well).
Spending as much time with these worms as I have, I’ve come to realize that some of my previous assumptions (you know what they say about ASSumptions! lol) were a little off target. As such, I thought it would be of value to put together a post based on my current knowledge-of/experience-with Euros.
Here is a run-down of interesting tidbits (my own observations supplemented with information obtained from reliable sources) about Euros:
NOTE: These are certainly not ALL new revelations (I have categorized accordingly) – and others who have worked with this worm will likely have some different experiences/perspectives. As always, please don’t treat my info as “gospel”.
1) Euros do not thrive in acidic conditions – This is something that needs to get added as a footnote to my “vermicomposting requirements” list. Unlike Red Worms (who seem to do just fine even when pH dips quite low), Euros shy away from acidic food/conditions and will tend not to thrive in a system that is excessively acidic. I first learned this from world-class worm-breeder and friend, George Mingin (who has been wonderfully generous with sharing his “trade secrets” on the WFA member’s forum), but it’s something I’ve also recently seen evidence of in my own systems.
When I’ve added deposits of coffee grounds in my VB48, these zones end up crawling with Red Worms, yet there is nary a Euro in sight (they are, however, found in high densities close by). Interestingly, a large deposit of mixed food waste – including some acidic materials like pineapple – recently added to an enclosed plastic tub system has also ended up devoid of Euros.
As a bit of an experiment I’ve added some (calcium-rich) rock dust (and will continue to do so when feeding) to see if helps a bit.
Just for fun I also sprinkled some on the surface in my VB48 in one small location. I can’t say for sure that the Euros were attracted to it, but I did find a fair number of them in that zone not too long afterwards. This is definitely something I need to investigate further.
2) Euros are very heat tolerant – I’m pretty sure not everyone will agree with me on this (including some academics). Once again I am relying on George Mingin’s vast experience with these worms since I myself have never had the opportunity to test this out. George says he’s had Euro beds reach 35 C (95 F) without any obvious signs of stress from the worms – whereas his Reds tend to start crawling out of the beds once temps reach 33 C (91.4 F). In “Vermiculture Technology” (and various other publications connected with Dr. Clive Edwards) Edwards & Dominguez suggest that 25 C (77 F) is the upper limit of this worm (35 C given as the upper limit for Reds).
I seem to recall, however, that Larry “Garbage Guru” said his Euros died off when it got really hot, while his Red Worms survived.
Bottom-line, you can take all this with a grain of salt! Lots of different factors come in to play here (moisture content, for example, can have a huge impact on tolerance of higher temps).
My main recommendation is simply NOT to assume they don’t handle heat well.
3) Euros are considerably larger than Red Worms (Eisenia fetida/andrei) – Although closely related to Reds, and similarly well-suited for vermicomposting, Euros are definitely a larger worm, and don’t really need any sort of super-nutrient diet (or other requirements) in order to attain and maintain that size.
Naturally, this means they are very well-suited for those also interested in raising live food organisms (for turtles, snakes, larger fish etc) and/or bait worms.
4) Euros don’t like to be disturbed – Anyone with a good memory of my “vermicomposting requirements” list will know that one of them is “peace and quiet”. This was added almost more as an afterthought (and as a bit of a joke), since I was focusing mostly on the requirements of Red Worms at the time (and they are actually pretty tolerant). In hindsight I’m glad I left it on the list because it is definitely applicable to European Nightcrawlers.
If you’ve ever given a Euro bin a good bump, or have started digging around vigorously, you likely know that this will almost always bring at least some of them (often the larger ones) to the surface – and some may even attempt to escape from the bin. It’s not too surprising, then, that they tend to be very restless after being shipped! My recommendation is add a really thick layer of dry, absorbent bedding over top of the worm habitat zone (not a bad idea in general) and/or keep the lid off and shine a bright light over top for a day or two to help them settle in.
All in all, this is definitely NOT something to worry too much about – just something to get used to if you’ve only ever worked with Reds. As a side-note, I want to point out that I’ve never witnessed a mass-exodus of these worms (such as can happen with Blue Worms), so I don’t actually consider them “flighty” or unpredictable.
And who knows – perhaps and advantage of this behavior is that you could use some sort of “grunting” technique for harvesting lots them at once!
5) Euro reproduction and maturation is somewhat slower than in Red Worms – A population of Euros will tend to grow at a slower rate than a population of Red Worms. Here are some numbers George M. shared with me from his own operation
Cocoon Laying – 3 cocoons per worm per week
Cocoon Incubation – 14-21 days
Viable worms per cocoon – ~3
Time to Maturity – 42 days
Cocoon Laying – 2 cocoons per worm per week
Cocoon Incubation – 21-28 days
Viable worms per cocoon – ~1
Time to Maturity – 56 days
Numbers from the literature (those from research conducted by Dr. Clive Edwards and associates) aren’t too much different, although incubation and maturity times for Euros tend to be greater. In all honesty, I tend to trust numbers from “real world” worm farming systems a bit more than experimental lab set-ups – but the long and the short of it is that all these stats should simply be used for comparative purposes, and even then it’s always going to totally depend on a variety of different conditions (eg. both George and the academics seem to keep their worms at 25 C / 77 F).
6) Euros often move in “reverse” (lol) – When Euros are disturbed, they commonly seem to first stick their tail out and then to emerge backwards. What’s interesting is that when I attempted to grab one of these tail tips one time it actually popped off. Makes me wonder if this is a protective mechanism? Obviously the head region is a lot more valuable to the worms than the tail tip (which they can easily grow back).
7) Euro coloration can vary a fair bit – In the past I assumed that Euros were always brownish in color (with their distinct banding pattern), since all the ones I’d dealt with had looked that way. I recently realized (when I started getting some from a new supplier up here in Canada) that they can actually be quite red in color, similar to Red Worms.
I think their diet can play an important role in this. I’ve noticed that previously-red Euros seem to gradually take on more of a brownish (even yellowish) color over time if they are feeding primarily on manure.
8) Euros prefer deep systems with higher moisture content – I am NOT going to claim here that these worms don’t thrive in deep, moist systems. What I WILL say, though, is that they clearly seem to do just fine in shallower – even open – systems. As I’ve mentioned, plenty of them have come out the bottom of my VB48 – but it’s important to note that there are still LOADS of them hanging out near the surface still.
What they really seem to like is sitting directly below sheets of newsprint or something similar. Most of my current Euro systems (VB48 included) are simply open bins with flyers, paper bags etc acting as a cover. The worms seem to be thriving!
Even shallow concrete mixing trays with NO cover whatsoever seem to work great!
9) Euros aren’t as good as Red Worms for processing waste materials – I’ve always just naturally assumed that Red Worms were a lot better for vermicomposting, but seeing the way my Euros voraciously feed on wastes and bedding alike, I’m not nearly as convinced of this! While it’s clear that vertical flow-through systems may not offer the best way to separate Euros from their castings, something I definitely would like to try out is some sort of horizontal flow-through, such as a multi-chamber composter or “walking windrow” (aka “wedge system”).
I am testing Euros in a number of other ways this season – in : 1) Typical “Backyard Composters”, 2) “Worm Towers”, and 3) Pet waste vermicomposting systems. I think they will have the potential to do very well in all of these – especially since these types of systems will be less prone to disturbance than your typical home “worm bin”.
All in all, I am very excited to have the opportunity to work a lot more with European Nightcrawlers, and my hope is that a lot more people will start to try them out as well.
I’d like to extend a big “THANKS” to George Mingin for his role in educating me (and many others) about this cool species!
As always – I’d love for readers to share their experiences here (in comments section) as well!