Worm composting / Vermicomposting


Traditional composting uses microbes to do the heavy lifting, but there are other natural processes that can work even faster. Worms are popular compost helpers – these little workers eat more than half their body mass every day. Worms burrow through garbage and eat soil that’s rich in anaerobic bacteria. They excrete soil with even more bacteria, and their waste has helpful aerobic bacteria instead of foul smelling anaerobes.

Worm Composter

Photo found on Flickr.com courtesy of CleanAirGardening.

Before you start composting with worms, its important to figure out how large of a composter is needed. You’ll need roughly one square foot of surface area for every pound of organic refuse that you generate per week. It’s okay to overestimate the area, but underestimating can result in waste that isn’t processed. Most earthworm activity takes place in the top inches of soil, so most of the waste they digest will likewise be found in the top inch or two of a worm compost bin.

Worm compost bins can be made from wood, plastic, styrofoam, and metal. The metal and wooden bins tend to weigh the most and they can rot or rust over time. Worm bins often include a drip tray for collecting moisture from the compost; that compost tea is prized for watering houseplants. Some worm composters also include a sieve tray to collect worm castings (that’s the polite term for worm poop). Worm castings make a great fertilizer and they can be used to restore biological activity to inert soil.

The two most popular worms for composting are Red Wrigglers (Eisenia foetida) and Red Earthworms (Lumbricus rubellus). These red earthworms are also known as manure worms, and they are different from Nightcrawlers (Lumbricus terrestris). Nightcrawlers (which are also known as Common Earthworms, Dew Worms, and Lob Worms) are found much deeper in the soil – except when it rains. Nightcrawlers don’t do well in compost bins, because they are always trying to burrow out of the bottom. Red worms can be found in leaf piles, compost heaps and old manure piles.

Red worms are quick workers. Finished compost will be ready in about two to three months, and redworms are also quick breeders. It takes about three weeks for fertilized eggs to hatch from their cocoon, and multiple worms will hatch from each cocoon. In three months the young worms will start laying their own eggs. Worm composting not only produces lots and lots of usable soil, it also produces an endless stream of bait for trout fishing!

There are a few quick steps to prepare a worm bin before adding worms. First, you need to install a bedding. The bedding will keep worms inside your bin without clogging the drainage holes in the bottom. The bedding should be made of organic material that the worms will nibble at, but its best to use something with a high carbon content, such as tree leaves, shredded paper, strips of cardboard, or coir (aka coconut fiber). You shouldn’t use peat moss or any other material that has high acidity – this can hurt the worms and make them work slower. Line the bottom of the compost bin with this bedding material, then sprinkle on water until the bedding is as wet as a wrung out sponge. This bedding should be kept damp to help regulate the temperature of the compost bin and so that worms have a supply of moisture to stay alive. On top of the bedding, put a good layer of soil. Then, put in the worms and your first batch of compost!

Worms vs Grubs

Grubs are an increasingly popular animal to use for composting waste. Grubs are voracious – they eat and breed even faster than earthworms, and they convert a higher percentage of compost into biomass. A popular grub is the larvae of the Soldier Fly – a type of fly with a long larval lifespan that lives for only about 7 days after growing wings. The adults have no mouth and are much less of an annoyance than stinging house flies. Soldier flies convert about 5 percent of the waste into friable compost and 20 percent of the compost will turn into additional grubs. They work extremely quickly – a bin full of grubs can process 5 lbs of compost daily.

If you have pet fish, birds, or reptiles, grubs make a nutritious animal snack. You can save money on pet food by raising grubs, and you’ll also save time by cutting down on trips to the store to pick up food.

{ 13 comments… read them below or add one }

Anne July 2, 2009 at 9:31 pm

There’s something I’ve been very curious about and maybe you can answer this. I have a wooden 2 layer composter that I am just starting to get the hang of using. The compost happens on the bottom level while new stuff is added to the top.. occasionally I look at the bottom level to stir it a bit, and also catch some worms to feed my snakes.

The thing I want to know is, how often is it optimal to stir or disrupt compost so as not to stress the worms and cocoons? Is once a week ok? More, less?

Also, if i take out the finished compost, right now I just pick through and remove the worms I can see and replace them in the new compost — is this the best way to do it? Am I losing all the babies? I honestly spent a lot of money on those worms! and, I was hoping to use them pretty regularly for my snakes. its been since last fall and they are making compost, but there really aren’t that many worms and I thought maybe I was stirring too often. I don’t want to deplete them, and I want them to be able to breed the most successfully.

Thanks so much for any info :}}


I’m actually more of a regular composting expert than a vermicomposting expert, so I’m going to have to admit that I am not sure about the answer to your question on this one.

So I’m going to recommend the best book on worm composting, Worms Eat My Garbage!

In general, I would say that if it looks like your worms are disappearing, you’re probably feeding them to your snakes faster than they can reproduce. I don’t think that the stirring is really going to cause any major problems for you per se, and that it’s just that the worms aren’t breeding fast enough to keep up with your pace.


Jan MacDonald September 2, 2009 at 12:39 pm

I live in West Scotland where New Zealand flat worm is present; I’ve found them on my allotment. My soil is relatively short of worms, but my compost heap seems to have a healthy enough population. I was considering ordering some Dendrobaena venata. I was told by someone that NZflat worm doesn’t eat all worms with the same relish. However another expert tells me they do and are a curse to wormeries!! Any advice Please


I’m based in the United States and unfortunately don’t have any knowledge of the New Zealand flatworm.

If you’ve got a healthy enough population now near your heap, my inclination would be to leave things alone rather than mess with it.


T Money November 25, 2009 at 1:13 am


I read on this page that the worms dont eat their bedding.
*So how does the newspaper disapear into compost?

* How do I get rid of fruit flies & ants

*What if the worms try to escape my bin at the holes in the bottom


I’d like to recommend this site that is specifically about worm composting.

I think I must have worded this page badly. Worms do also consume the bedding material over time. So shredded newspaper or coir or shredded cardboard will disappear and turn into worm castings.

For ants, you can keep the worm bin in a garage or inside or someplace where ants can’t easily find the bin. If you have an ant problem, you could try spraying the outside of the bin with something non-toxic like Orange Guard. Don’t spray it inside the bin though!

With fruit flies, you want to make sure any fruit scraps are buried way down in the bin under the bedding. Or alternatively, you can stop adding fruit scraps completely, and stick to vegetables and other materials that don’t attract fruit flies. They are very hard to get rid of, once you have them.

If massive amounts of worms are trying to escape, you probably have some kind of problem in the bin and the worms aren’t happy there. If it’s just a few, it’s not a big deal. In one of my bins, the worms go back and forth between the top tray where the food and bedding is, and the bottom moisture collection tray. It just depends on where they want to be.


Falkor March 10, 2010 at 3:39 am

Is shredded cocoanut alright for vermiculture red worms? What about food that has preservatives in it?

Also, for the ants(T-money), we put each of the legs of our worm bin into cups of water; kind of like a little moats. It has worked well.


Falkor March 10, 2010 at 3:42 am

Is shredded cocoanut alright for vermiculture red worms? Also, food with preservatives in it?

T-money: We put each leg of out worm bin into cups of water, kind of like little moats. It worked pretty well.


Roch April 16, 2011 at 2:53 pm

Is there a link between the moisture and the appearance of mites in the bing? My bing is quite moist and there’s white a bit of those bugs in there?


Steve April 18, 2011 at 2:09 pm

@Roch, Bugs will find a place with moisture and food so it’s hard to keep them out. It’s not unusual to have them and they will not hard anything.


Sock Lady April 19, 2011 at 2:45 pm

I am having a problem with grub worms. What should I do to get rid of the many grub worms that are in my bin right now?


Steve April 22, 2011 at 11:02 am

@Sock Lady, Not knowing which type you have there are several options. In the past I had a similar problem. I had large white grubs in my bins; I dumped out my finished compost on a tarp and picked them out. If they are large you can try that, or use something like this: http://www.cleanairgardening.com/grub-beater.html


Anna September 18, 2011 at 5:38 pm

I have a worm composting bin which I started with redworms. A neighbor, unsolicited, dumped a handful of grubs in the bin. Are the grubs and redworms compatible? Upon discovery, I removed all the grubs that I could find on the surface but I am sure some must have submerged.


Steve September 19, 2011 at 10:40 am

@Anna, Yes red worms and grubs are compatible and should live amicably together.


Rusty June 7, 2012 at 4:35 am

I’m a former worm composter and want to share a cautionary tale: do not (DO NOT) put pineapple refuse in your worm bin! It’s tempting because pineapples produce a lot of leftover material. The problem is acidity; it dissolves the worms. Poor little boogers. I still feel bad and there’s a lingering stench three years later!


Steve June 12, 2012 at 12:59 pm

@Rusty, Thanks for sharing rusty, good advice.


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