Quick Facts About Worm Composting

Worm Bin

New to worm composting? Looking for some quick and dirty info before jumping in head-first? Well this is will be a great place to get started.

Worm composting (also known as vermicomposting) involves the breakdown of organic wastes via the joint action of worms and microorganisms (although there are often other critters that lend a hand)

Regular (soil and garden) earthworms cannot be used for worm composting. They will die if added to an indoor worm bin.

Soil worms will however congregate in the lower regions of outdoor bins (if open to surrounding soil)

Composting worms are specialized surface dwellers (not burrowers), typically living in very rich organic matter such as manure, compost heaps or leaf litter

Most common variety used is Eisenia fetida (also spelled ‘foetida‘), although it’s larger cousin, Eisenia hortensis (a.k.a. the ‘European Nightcrawler’) is commonly used as well (more commonly to be sold as bait worms)

Common names for E. fetida include: red worm, red wiggler, brandling worm, manure worm, tiger worm

You won’t likely find this species on your property (unless you live on a farm, or happen to introduce them into your compost heap).

Lumbricus rubellus is another species (and also a small reddish worm) sometimes used for vermicomposting, but is not as effective as E. fetida

It is widely believed that a composting worm can process the equivalent of it’s own weight in waste each day. Under highly optimum conditions (not likely to be attained with a small home system) red worms have been found to process multiple times their own weight! This is very much dependent on the foodstock and how well managed the system is.

A reasonable guideline to follow is 1/4-1/2 total worm weight in waste per day. So if you have a pound of worms, they should be able to process roughly 1/4-1/2 lb of food waste per day. Keep in mind however that you may need to feed them less during the first couple months since they usually require a period of acclimation when added to a new system.

Red worms technically graze on the microbial community that colonizes waste materials - not really the waste itself (although they certainly ingest some of the rotting waste in the process). Some research has indicated that protozoans are the primary food source, while there is also evidence that fungi and other microbes are consumed as well.

There have been a number of research studies indicating that vermicomposting can significantly reduce levels of pathogens in waste materials, such as biosolids.

Red worms love (and can tolerate) very high levels of moisture content (80-90%), but they also require oxygen so it’s important to find the right balance

One lb of composting worms is estimated to consist of approximately 1000 individuals, and can cost anywhere from $15 to $40 USD

Surface area far more important than depth when it comes to worm bins (ie tubs work much better than buckets)

Regular light is harmful to worms but red light is not

Red worm eggs look like tiny straw-coloured lemons

Baby worms look like very small versions of the adults (but have less red pigment)

Adding crushed egg shells (or other calcium sources) can help stimulate worm reproduction

Stay tuned for more Worm composting ‘Quick Facts’!

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28 comments

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ronald thomson
#1. June 8th, 2007, at 1:19 PM.

Very good introduction. All facts necessary to understand the basics very clearly given. As a lecturer in vermicomposting to local garden clubs and organic people in general, I can recommend your site to anybody starting out. Your list of references is extensive for the more advanced person.
well done

ronald thomson from western cape, south africa

Bentley
#2. June 11th, 2007, at 3:55 PM.

Hi Ronald,
I sent you an email, but just thought I’d reply here as well. Thanks very much for your kind words! Given your extensive experience in the field, your positive feedback certainly makes me feel like I’m on the right track here.

Unfortunately I haven’t had nearly the amount of time necessary to really develop the site as much I’d like, but all in good time I’m sure!

Thanks again

CHADWICK THOMPSON
#3. August 30th, 2007, at 2:16 AM.

I have a worm bin and have tons of little white spiders crawling all over the worms, lid, just every where. Can you point me in a direction on what these may be and how to get rid of them. It seems like the worms are not happy with the spiders all over them.

thank you,

chadwick
chadwwwick@gmail.com

Adriana Michael
#4. August 30th, 2007, at 4:42 AM.

Very nice introduction and reference material, especially to newcomers. I started a bin a couple of months ago and notice it is a real trial and error process until you find the right balance. A couple of times I left the bin totally closed for more than 4 days and it became too humid. I found red tiny spiders once, white tiny creatures another. I simply sprayed a little bit of Citrofresh (www.citrofresh.com) on the surface. I was told that once the worms mature at around three months I should not let their eggs go along with the nice black soil, because they are not native to where I live now in Ottawa, Canada. Should they always stay in a closed bin or indoor planter?. Thank you for your comments. I would like to include an editorial on this topic in an upcoming edition of Organic & Wellness News.

Bentley
#5. August 30th, 2007, at 3:45 PM.

Hi Chadwick,
The creatures you have in your bin are almost certainly mites (which are in fact related to spiders). Worm bins can attract a wide variety of these creatures, and for the most part they are not harmful to the worms. Some are scavengers, while others can actually prey upon the larvae of annoying flying pests like fungus gnats.
In my experience, the round white mites that crawl over the worms are usually a sign of a system that is out of balance. I’m pretty sure they get rid of the dead bodies of the worms (and perhaps even start feeding on the dying worms as well).
How long has your bin been active? Are there any odors coming from it when you open it up?

I’d more than likely start up a second small bin and once it was aged, would add a bunch of the healthy worms from the other bin.

I have a picture of a brown mite and will see if I can get some pictures of other mites. In the meantime you can check out this page:
http://www.happydranch.com/87.html

Bentley
#6. August 30th, 2007, at 4:03 PM.

Hi Adriana,
Thanks for stopping by and for your nice comments! I will definitely be adding a lot more content in coming months.

The worms typically used for composting, Eisenia fetida are totally fine in either an indoor or outdoor system. They are very much adapted for life in rich organic matter, not soil, so the risk of them escaping out into the local environment isn’t that high.
Plus, I can pretty much guarantee that there are already many farms in the Ottawa area (and Ontario in general) that already have aged manure piles inoculated with redworms (can in fact be a great place to find a large free source of composting worms).

My first experience with red wigglers was when I found a huge pile of aged horse manure at a farm near Stratford. It was absolutely LOADED with composting worms!

Rich
#7. November 3rd, 2007, at 6:07 PM.

Thank you for taking questions regarding vermicomposting. I have trouble distinguishing between the pictures I’ve seen of the brownish mites and eggs. I have a lot of whichever it is, though my bin is only 3 weeks old. I also have thousands of very tiny white spider like creatures that crawl on the surfaces and walls. They don’t look like the mite pictures though. I feed my worms a few times a week juicing pulp, coffee grounds and eggshells because this is about the only waste I have. They seem to like it, but I’ve read that too much juicing pulp could increase the mite infestation. Any suggestions would be appreciated.
Thank you!

Bentley
#8. November 4th, 2007, at 4:26 AM.

Hi Rich,
I assume you are talking about worm eggs? If so, they are much bigger than any mites you are likely to encounter in your bin.
If you are lots of them they are almost certainly mites - some varieties seem to move very slowly.

If you have small insect-like creatures and they are hugely abundant, they have to be either mites or springtails - the fact that they are spider-like make me think mites. There are many many species of mites, and it is quite possible that you just haven’t seen a picture of the variety in your bin. I’m actually going to be writing a post about mites fairly soon.

If your juicing pulp is solely citrus you may encounter some issues with acidity. Hopefully you are adding bedding on a fairly regular basis to help soak up excess moisture. Glad to hear you are adding egg shells (I typically dry mine and grind them up as much as possible).

Sounds like you are doing a pretty good job to me!

Jesse
#9. November 6th, 2007, at 2:07 AM.

Hello!
I have a new composting bin with only about 50 worms right now. I am realizing that I am overfeeding them. About a dozen have “jumped ship” today out of their cedar home. I found them all over my kitchen floor this evening. As I was cleaning out their wooden bin, I found hundreds of small, white, round things- what I think are eggs- all over their boddies and in the compost material. I just wanted to double check to make sure these are in-fact worm eggs. Or are they something else caused by the overfeeding? They are about the size of the period at the end of this sentence.

One other thing- I live in a very dry environment (Wyoming). I have a hard time keeping the worm bedding moist from day-to-day. I am worried that if I go out of town, they will dry up very quickly. As I mentioned above, my worms live in a cedar box. Does anyone have any suggestions for how I might keep their bedding more moist?
Thank you for your help!

Bentley
#10. November 6th, 2007, at 2:53 AM.

Hi Jesse,
Thanks for popping by.
Overfeeding when you have lots of worms is quite easy to do (especially early on), so I have no trouble believing you could do it with 50!
What kind of worms are they by the way? Given the small number I’m curious if you are using soil dwelling worms (since composting worms come in much larger numbers when you buy them).

Aside from overfeeding, the oils in cedar wood could potentially cause issues in a worm bin as well (but I suspect its the food).

The “small, white, round things” are in fact mites. Worm eggs are straw coloured and much larger. The type of mite you have described does look a lot like some sort of egg and often increases in abundance when you overfeed and/or when the worm are dying in general. While they don’t actually attack healthy worms, I have seen these mites coating worms that were close to dying, presumably finishing them off. They certainly get rid of the worm bodies in a hurry. Anyway, definitely leave the bin without new food for awhile (maybe as much as a couple weeks) then add some more (composting) worms. You chances of starving your worms are a lot less than overfeeding, so definitely err on the side of caution early on (once they are well established in the system worms will be able to process wastes faster).

Re: your drying issue (and the fact that you are using cedar) - I would definitely line the inside of your box with 1 or 2 layers of cardboard. This should help to keep some of the moisture in while still allowing the bin to ‘breathe’. Adding lots of water-rich foods should help as well (but again, use caution when first starting out).

Jesse
#11. November 6th, 2007, at 8:42 PM.

Bentley,
Thank you for the helpful information. I am using redworms. I recieved as small bunch of them from a friend. I’ve been hoping that their numbers will increase. And I do think that is the case. Many of the worms I see now are very small. This leads me to believe they are young, while the older worms are dying out.

The mites make sense. I cleaned out the worms’ large cedar bin last night, and put them in a small, open plastic container with fresh bedding and a tiny bit of food. There were still mites covering them, but hopefully I can restor the balance and they will survive.

I will experiment with lining the cedar home to keep it more moist. The box that I ordred has three levels, each about 4 inches deep. The bottom of each level is large wire mesh. This is how some of the worms “jumped ship” as I mentioned earlier. I had the bottom lined with paper towel, but they must have gotten out around the edges.

One more question- why would the levels have such large mesh? Is it intended so that the worms can move up and down through each level when I have that much compost?

Thanks again for your help!
Jesse

Bentley
#12. November 6th, 2007, at 8:57 PM.

Hi again Jesse,
Glad to hear that you are using redworms! Also glad you were able to get some from a friend (always a great option when possible).

Your multi-level worm bin sounds like a ‘worm chalet’ or ‘worm factory’ (or something similar). The idea behind these stacked systems is that when the layer is almost full you can put new bedding and food in the next level and the worms will migrate upwards. You continue this process until you’ve almost finised the top level (4 or 5 levels would probably work better than 3) - by this time the very bottom tray should be free of worms and the compost can be used so you can dump it out and add it to the top of the system (filled with new bedding/food).

When conditions are ideal in the bin you shouldn’t encounter too much migration (although no matter what you’ll likely find a few worms in the bottom reservoir from time to time) - in your case, once conditions became intolerable the worms simply used an escape route that was available to them.

Rebekah
#13. January 20th, 2008, at 1:05 AM.

Can dog poop be used in a worm bin assuming that the dog is a small breed (not large amounts of feces every day in other words), healthy, free of internal parasites, and not receiving medications? I would really love to find a use for the waste our little house dog produces from her expensive organic dog food…..but the books always say to keep it off the garden due to pathogens. Can worms help with this?

Bentley
#14. January 20th, 2008, at 5:41 AM.

Hi Rebekah,
That’s a good question! While I’m sure some of the concerns are warranted when it comes to certain types of feces, I personally feel these things get blown out of proportion somewhat.

That being said, I personally wouldn’t add cat and/or dog feces to any of my ‘regular’ bins . Aside from any potential health issues, the material wouldn’t be very enjoyable to work with (lots of bad odour and potential issues with ammonia). But setting up a separate system, dedicated to pet wastes isn’t a bad idea. Ideally it would be an outdoor system, but if you have enough bedding material and make sure all the feces is buried, you could potentially keep an indoor bin as well.

Anyway, I’ll leave it at that for now - hoping to write a post about this topic before too long.

Thanks again

Lynda
#15. March 8th, 2008, at 5:36 PM.

My new favorite site! I have just ordered a worm bin (tower Type) and I am excited about composting all of the kitchen waste i have have. I just hate throwing it out. Your site has answered so many questions I have, but I am concerned about one thing. I live in Texas and the summers can been extemely hot. Will I need to move the worm bin indoors? I was planning on keeping it in a shady spot in the yard or patio. I’m having trouble getting used to the idea of having worms in my kitchen, so I’ll need time to figure out where in the house they can go.

Bentley
#16. March 16th, 2008, at 1:22 PM.

Wow - thanks Lynda! Apologies for the delay replying!
In hot climates it is definitely important to make sure your worms are kept somewhat cool - they are much more tolerant of heat than ‘normal’ earthworms, but do have limits. I can only imagine how hot a stackable worm system would get in the hot Texas summer sun!
If you have a nice shady spot on your property you might be ok. Alternatively, you could build an outdoor system partially set in the ground - just dig a hole then partially fill it with lot of shredded cardboard and food waste - make sure you add some water as well. Leave it sit for a week or so then add your worms (make sure everything is starting to rot and well moistened before doing so). You can then put a framed structure over top and start adding your kitchen scraps. It wouldn’t hurt if your composter was painted white (lessening the heat absorption) and well ventilated. You will likely need to add quite a bit of water to keep it moist since it is an outdoor summer system.

Of course you COULD also work on your fear re: having worms in the house too!

In a Rubbermaid tub bin you can literally keep them anywhere without offending anyone (assuming the bin is well maintained).

Hope this helps!

Jorge Luis Ricardez
#17. April 1st, 2008, at 5:49 PM.

I have a question about the vermocomposting culture… Is the pH important for a Esesnia foetida culture? How dos is it matter?
Thanks! My reason its because I have a lot of goat manure and want start with vermicompsting…

Bentley
#18. April 1st, 2008, at 6:50 PM.

Hi Jorge,
Red Worms have a very wide range of pH tolerance (something like 4-9), but there are other factors to keep in mind. Higher pH tends to favour the release of ammonia gas from waste materials (and soils), thus lowering the value of your compost and potentially harming the worms. The pH can also have a significant impact on the ecosystem of your worm bin. Lower (acidic) pH tends to favour fungi over bacteria.
Generally, I’d recommend a somewhat acidic pH (maybe between 6 and 7), but really I don’t worry too much about it.
If I was going to be using goat manure, I would likely mix it with shredded cardboard or straw and let it age for at least a week or two before adding the worms (even then you should add only a few and see how they respond). If you have a worm system up and running already, you may actually be able to add fresh goat manure directly on top (I’d still recommend adding some carbon-rich material at the same time though)

Mike P of Virginia
#19. April 16th, 2008, at 11:36 AM.

I have been using a general compost pile for over twenty years, but I thought I would venture into vermicomposting. I purchased the 5 tray wooden worm farm/condo and I am getting ready to set it up. Unfortunately the instructions provided with the unit was just general instructions on vermicomposting from the US-EPA (Environmental Protection Agency). It did not provide the specifics associated with the 5 tray system I had hoped they would provide.

I was planning to start with the first three lower bins. Place a single layer of newspaper in the bottome of each. Fill each of the three bins with shredded computer paper, partialy composted grass clippings, peat moss, and soil. Let the unit sit for a week and then add a pound of the red worms to the lowest bin. I am going to monitor the temperature of the 3 lower bins and the ambient temperature with a four channel recording thermocouple. I want to see if I can detect the worm movement from the lowest bin to the upper bin via a change in the bin temperature. After about two weeks, I will set up the fourth bin and the fifth bin will follow a week later. After the fouth or fifth week with worms in the bin I plan to empty the lower bin and rotate it to the top with fresh shredded computer paper, partialy composted grass clippings, peat moss, and soil. I will also occasionally monitor the pH and the moisture content of the bins.

Do you have any additional suggestions?

Bentley
#20. April 16th, 2008, at 1:21 PM.

Wow Mike,
Sounds like you are a serious composter! You also seem to be taking a different approach when it comes to the use of a stackable bin system.
Generally, these bins are designed based on the ‘continuous flow’ vermicomposting concept - i.e. waste materials are continually added in a given direction and worms just naturally follow, occupying the zones with the best food and leaving their waste (castings) behind or below them.

Usually, with a bin like the ‘Chalet’ you would simply start the bottom tray and treat it as an independent worm bin. Once it has reached it’s capacity you then added the second tray (which ideally has had some wastes and bedding aging in it for a bit) and the worms then start to migrate upwards into it, and so on and so forth.

Putting newspaper down on the very bottom tray is definitely a good idea. I’m not sure I would recommend doing so for any of the other trays since this will impede the movement of the worms.

Your idea for measuring temperature differences sounds intriguing! I’d love to find out how it works out for you.

Mike P of Virginia
#21. April 17th, 2008, at 1:54 AM.

How much time would you recommend for setting up each successessive bin? Should it be based on observations of the first bin or based on time, or what? Should food be added to a worm occupied bin or just to a new bin?

As far as the setting up the first three bins in my experiment I just thought I would collect some data to see if I can determine if the migratory habits of the worms can be determined by a change in the temperature in the bins. My hypothysis is that temperature should increase with the increased activity in a bin as the worms start eating in a bin. After the initial testing of the first three bins, I plan to go to adding a bin after a set period of time and after the fifth bin addition I would start to rotate the lower bin to the upper bin after collecting the castings.

Bentley
#22. April 18th, 2008, at 3:11 PM.

Hey Mike - sorry for the delay responding.
It’s not so much about a specific time to wait as it is about the amount of material in the tray, and how well processed it is. If the tray is nearly full and there is a lot of dark vermicompost present then it might be time to add another tray with some bedding and food scraps. At that point you should no longer add food to the first tray, and should wait for the worms to move into the second tray and start feeding on whats there before adding new food waste to that tray.

ali
#23. April 23rd, 2008, at 4:18 PM.

Hello all.
Very informative here! I noticed that someone was using paper towels rather than newspaper. Isn’t there a chance of harming the worms with bleach that may be contained in paper towels and napkins? I’ve read somewhere not to use papertowels for spills on fabrics due to how they’re made.
Thanks!
Ali

Bentley
#24. April 24th, 2008, at 2:48 PM.

Hi Ali,
That is an excellent question. I generally only use any sort of white paper (including paper towels) in moderation for that very reason. I recall adding a LOT of shredded office paper to one of my worm bins a a number of years ago, and the worms did not seem to like it at all. I’m pretty sure there was something in the paper that was causing them irritation.

S Bates
#25. May 6th, 2008, at 7:14 PM.

At what external temperature can my plastic worm container, with worms, be moved outdoor? There is no odour but space is a concern.

Bentley
#26. May 7th, 2008, at 3:12 AM.

As long as you are not going below freezing at night you should be able to take the worms out at any point

Free
#27. May 7th, 2008, at 3:20 AM.

The internal temp of my bin is quite warm. I live in Las Vegas, so I have my bin indoors to keep from overheating. My house is about 78 degrees - do I need to worry about the internal temperature of the bin.

Also, some maggots grew on the inside grooves of the bin and then died when the few food particles that were there were eaten. Is there ever a problem w/ maggots growing in the decomposing food?

Bentley
#28. May 7th, 2008, at 6:16 PM.

Ahhh ok - didn’t realize we were talking about the other end of the spectrum (too hot). You would definitely need to keep the system well shaded if outdoors in a hot climate like that. Creating some sort of in-ground system might help to keep the worms cool.

I have never had house fly maggots (what I generally associate with the word “maggot”) crop up in my systems. Not sure if this is the sort of maggot you are talking about. There are also Soldier Flies which are common in warm regions. Their larvae consume organic waste but won’t harm your worms or anything like that.
Generally speaking, I wouldn’t say there is too much of an issue with large maggot infestations developing (other than the tiny maggots of Fruit Flies and Fungus Gnats).

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