Known as vermicomposting, raising worms specifically for the purpose of harvesting the castings to use as garden fertilizer is both an organic and effective method for giving your vegetables the nutrients they need to thrive.
Castings are worm poop – waste – what worms “cast off” as excrement, and to a gardener, it is pure black gold.
There is a learning curve when it comes to beginning a vermicomposting project. When I bought my first worms, I simply had to trust that the retailer was indeed selling me red wigglers.
To me, a worm is a worm. However, I am going to share with you all that I learned along the way. But first:
Why vermicomposting in the first place?
Worm casting used as fertilizer provides all sorts nutrients and trace minerals (such as nitrogen, phosphorus, and potassium). It rejuvenates and conditions tired soil to better hold those nutrients in place (so they do not wash away with watering).
The nutrients they provide are naturally water-soluble, meaning that they are in a form that plants can metabolize on a cellular level … which is WHY it works.
This is because of all the microbial life (germs) at work. Worm castings also contain that slimy stuff (the mucus that worms produce). That slime helps to hold those nutrients in place in the soil during watering so that it better retains the nutrients and moisture longer. It is just nature’s way.
Castings not only provide an excellent source of nutrient-rich organic fertilizer but it also serves as a soil conditioner.
Some studies indicate that worm castings contain significantly fewer contaminants and more nutrients than just regular composted organic matter that has never seen a worm.
So while your regular compost is great, vermicompost is even better. The best part is that vermicomposting is completely chemical-free, and easy to do.
Of course, there are downsides to vermicomposting.
- Castings are not cheap to buy. A 15 lb. bag can cost as much as $35, and that doesn’t go very far.
- The castings are not fun to handle.
I have a way around BOTH problems! There are a couple methods that will allow you to grow your own castings cheaply, without having to handle the castings yourself.
Housing Your Vermicomposting Worms
Assuming you are running a small (home) worm farm operation there are two basic ways to raise compost worms for their castings.
One is the bin method and one is the tower method. If done properly, they both work quite well. This is really the first decision you need to make when starting your vermicomposting project.
The bin method of vermicomposting.
You can build a bin, buy it, create it from repurposed materials, or just wing it. Just be sure there are adequate air & drainage holes. The bin method can also make a great project for teaching vermicomposting for kids.
Consider different approaches to bin construction before settling on one because each one has its own unique set of pros and cons. Other things to keep in mind when starting your vermicomposting project:
- Don’t use metal (retains too much heat, can rust, and can leach heavy metals into the otherwise healthy compost and castings).
- If you use wood, avoid cedars and redwood because they have resinous oils that can be harmful to your worms or to your food. Choose a wood that will hold up well to very moist conditions without rotting but that has not been treated with hazardous chemicals.
- Large plastic tote bins or buckets are a pretty safe bet.
The Tower Method of vermicomposting
This method is quick and simple. Once set into place, it never needs cleaning or casting removal.
- Put a bunch of holes in a PVC pipe.
- Plant it permanently and vertically in a deep hole in the middle of the garden.
- Backfill it.
- Place in some worms.
- Start filling with kitchen scrapes a couple times a week.
There are pros and cons to each method, and you can decide what will work best for you and your homestead. Vermicomposting is not an “all or nothing” project. You can go back and forth between methods, or have both going at the same time. Some pros and cons to each method:
Now that you have your vermicomposting going, and your worms are making castings, how do you apply them?
If you are using the tower method, the worms spread their castings for you – all on their own (so no yuck factor). But with the bin method, you will have to harvest and then apply the castings to the garden yourself. There are a several ways you can do it.
- Mix the solid castings directly into the soil just like you would regular compost. That slimy mucus I spoke of earlier creates a time release fertilizer which cannot burn plants so this method is safe for your plants.
- Make compost tea and water your plants with it.
- Diluted with 50% water, you can turn it into a spray for use right on the plant’s foliage but be careful. This method is sans the slime and could be too strong. Such over-fertilization can cause nitrogen burn.
What kind of vermicomposting worms do I use and where do I find them?
Note that these worms are neither the kind that crawls up on the sidewalk after a storm nor are they the kind that anglers typically use as bait (although you can).
For vermicomposting, most folks go with red wigglers (Eisenia fetida or Eisenia andrei) because they adapt best to the shallow depths of the typical worm bin, while comsuming decomposing vegetable matter. Other species lto consider are:
- Dilong (Lumbricus rubellus)
- European nightcrawlers (Eisenia hortensis)
- African nightcrawlers (Eudrilus eugeniae).
We do not recommend the Canadian nightcrawlers (Lumbricus terrestris) or the common earthworm as they like to go much deeper and decaying kitchen scraps may not be their preferred diet. Vermicomposting worms are drawn to compost specifically. All others, not so much.
In scientific terms, Wikipedia puts it like this:
Composting worms which are detritivorous (eaters of trash), such as the red wiggler Eisenia fetidae, are epigeic (surface dwellers) together with symbiotic associated microbes are the ideal vectors for decomposing food waste.
Common earthworms such as Lumbricus terrestris are anecic (deep burrowing) species and hence unsuitable for use in a closed system.Wikipedia
Keep it simple, and get red wigglers for your vermicomposting. It’s important here is to choose a composting worm species that is
- suited your to climate
- adapts well to living & procreating in the confined space of a worm bin (assuming bins are your method of choice)
- is happy to eat rotting kitchen scrapes (or other decomposing plant matter – you know, the stuff from your garden that you won’t eat).
You can find such worms online, at garden centers, or bait stores or you can collect them yourself from existing compost piles (which tend to attract the right kinds of worms in the first place).
All that said, there is a rumor/hypothesis that says some red wigglers can be invasive in the northern US. Check this article for details: Do Composting Worms Pose a Threat As An Invasive Species.
Now you know why to vermicompost, the basic (home) methods and their pros & cons. You also know what kind of worms to buy & where, and how to make use of the gardener’s black gold … castings.
How will you start your vermicomposting project?
Heather’s homesteading journey started in 2006, with baby steps: first, she got a few raised beds, some chickens, and rabbits. Over the years, she amassed a wealth of homesteading knowledge, knowledge that you can find in the articles of this blog.
20 thoughts on “Comparing Vermicomposting Methods – An Overview”
Wow! This is an amazing source of information! I’m just now trying to wrap my head around composting in general, and hopefully that will happen soon. When it’s time to take the next step, I know where I’ll come to get my info! Definitely sharing this!
I had never heard of the tower method before! I would definitely prefer to do that over sorting out worm castings. Gross.
Thank you, Heather! I am thrilled and honored to have my post shared on your blog! It was such a fun post to write and a subject near and dear to my heart because I have seen the benefits first hand right in my own garden. I am a vermicomposting believer!
What a great source of information. I also had never heard about worm towers, and I think they are an awesome idea. I personally will be using a bin, because my raised beds and containers will need direct application, plus the kids will love the ‘yuck factor’ of seeing the worms do their thing in a bin. 🙂 Great article, thanks!
We are trying to do composting this year. Last year was the first year our garden actually turned out good so this year I want to make some nice composted soil to put on it. Thanks for the information!
I’ve never really learned about composting growing up in NYC-so this is quite eye opening to me. Thanks for making our world a bit greener and educating about it too 🙂
This is a very interesting article. I have always wanted to compost, but have never gotten around to it. I think I could easily do the tower one. Less yuck and great stuff for my garden!
Heather, I am starting a barrel garden this year. https://www.youtube.com/watch?v=ufEQ6ZljJBE
I am ready to add the soil material and worms. Do you know a good soil mix that worms find “yummy” and will remain reasonably light weight? I don’t want a barrel full of heavy mud… just a nice soil for vegtables and worms.
I personally like to add coffee grounds (I don’t drink coffee at home myself but the coffee shops offer their used grounds free) to help attract the worms
Ewwww, but completely useful. Great tips-I am garden illiterate and never really understood the exact benefits of raising worms
I love composting! It intrigues me so much to learn about everything to about it! I have a box set up that I compost in, I personally use any type of worms to throw in the box! If my kids find worms they put them in there! It is like gold for gardeners! It is easier then most people think! Thanks for sharing such a great article! http://www.janrosereviews.com
Love this Jo! I will hopefully be starting ours soon. I actually will start with the bin method until I can have enough worms to move some of the worms to the gardens in a tower method. We actually have two gardens so will need to have several towers eventually. Thanks so very much for the wonderful information.
So much great information I have to share with my mother in law who gardens.
Thanks for the great post. I was told red wigglers cannot overwinter in our Colorado climate, so keep my bins in the garage in winter. However they do survive in my compost bins. I find them next to my bins in leaves every spring. I’ve also been told my compost bins are not hot enough to be truly composting if worms live there. Meaning seeds survive. I’m ok with that. This winter I got lots of condensation under the lid, so I think I’m making progress.
Hi Terri. Red wiggler should be able to overwinter just fine so long as they able to get below the frost line, However, it sounds like you are using bins, in which case, they cannot get below the frost line. If you are keeping them in the garage in bins, and they still survive, then either your winters do not get that cold for a long enough time OR you garage stays fairly warm. Not sure which. Regardless, you are fortunate if they are surviving in spite of the temps. Honestly, I am confused by “compost bins are not hot enough to be truly composting if worms live there.” Whether or not worms are present has nothing to do with whether or not compost is truly composting. And technically, neither do temps. You can compost in subzero temps… it just takes a WHOLE LOT longer to do it. Eventually, all organic material will compost regardless of the temp. But when it is HOT outside, yes … it will compost much faster than at freezing. Make sense?
Would the tower method work in a raised garden? Since the worms would be ‘contained’. Also using the tower method, is
it cooler for the worms than if they were living above ground in a container? I’ll be living in central Texas soon and it gets hot
in the summer. Thanks
Thanks for your question, extexanwannabee! I think that would depend on whether there is an impenetrable barrier at the bottom of the raised bed and the bottom of the pipe. The worms need to be able to escape extreme cold and heat. If they cannot get below the frost line and find a constant temp, then no. I don’t think that will be good for them. Will they survive? Maybe, but without an escape from extreme weather, I cannot promise that. As for your second question, it might be cooler for the worms in a container, but it depends on how cool the room is. If in a container in a room at 70-75 degrees, then they will be cooler than in a room that is at 80-85 degrees. BUT so long as they are somewhere/anywhere within an acceptable temp range, they should be just fine. Does that answer your question?
I live in Phoenix, AZ and have been bin composting for years. I can’t stress enough how these little guys have grown on me. Once a month we get this incredible ‘mud’ to spread in our garden and they eat almost anything from fruit and vegetable scraps to dryer lint and even dog hair. I sweep our concrete floors and toss that in too. The only problem is fruit flies.
My wife finally put her foot down about the fruit flies and also wants to reclaim the shower where they reside. They have to be indoors due to the hellish Phoenix summer heat (I’ve cooked them twice before).
I’d never heard of the tower method but it makes perfect sense. I was going to just bury the bins and their contents and hope for the best. Now I can still feed them and know that they are better off in the wild.
Thanks so much for the simple solution to my problem. My wife sends here heartfelt thanks as well.
Hi Heather, love this article. Glad you had your friend share the info. The article says to bury the pipe deep, but doesn’t give any rough guides as to how deep to go. Any suggestions?
Love your site.
about 6 inches