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Vermicompost is a method of composting that involves worms.
The worms have an environment that contains them and you give them certain food scraps and other material they can break down.
(You can read about what to feed them and what not to feed them here.)
As the worms break down the food and other material, they excrete it into what is known as worm castings.
Worm castings is the worm poop, also known as vermicompost. Some people have referred to vermicompost as “black gold”.
Worm castings are a form of fertilizer and they are considered to be better than compost itself.
Is this a must-have product for the garden? In my opinion, yes, and I will explain why…
Why would you want worm castings?
There are many reasons why you would want worm castings, whether you start your own worm farm or purchase the castings. I highly recommend starting a worm farm. It doesn’t need to be anything too extravagant or cost a lot of money and for what I have seen, worm castings can cost a bit of money.
There are many benefits to vermicomposting and considering that there really isn’t too much involved once you get the system figured out and going, anyone can do it.
Here are some of those benefits…
Soil
Worm castings is the best soil conditioner you might be able to get for your soil.
The worm casting improve the soil structure by holding the soil particles and minerals together.
They create humus.
The casting help control soil nutrients.
Worm casting help retain moisture and reduce erosion.
Plants
You can add it to all of your garden plants, whether in the ground or in pots.
They will not burn your plants like a lot of other fertilizers might do, so you can use as much as you want and not worry about killing your plants.
They are the best way to increase plant growth and plant yield in the garden.
Environment
Vermicomposting reduces the amount of waste that goes into the landfill by recycling waste on-site.
It is 100% natural! This means you might be able to get rid of your chemically based fertilizers.
How do you get worm castings?
Not all of us are fortunate enough to have earthworms take over your garden bed on their own. Joy and I have had some sort of garden ever since we got married in 2006 and I do not believe we have ever had earthworms move in by them selves.
It wasn’t until recently that we introduced worms from the worm composting bins into the garden. They are now exploding in numbers.
I love seeing worms thriving in the garden beds. Seeing them stick around tells me they don’t mind the environment and they are creating castings without any additional work from me…other than making sure they have food and moisture.
So how do you get worm castings? Here are a few ideas…
Buy Worm Castings
You can buy worm castings online or in some garden departments. I wouldn’t say that buying worm castings is cheap when you can get them yourself by raising earthworms at nearly no cost, or at least at a very low cost.
But when you don’t have a worm composting bin and don’t have the space for one, you might consider buying some castings.
Buy Worms to Put in Your Garden
If you are one of the unlucky ones, like I was, that don’t already have worms in your garden beds, you can buy earthworms and put them in your garden and they will create the worm castings right there in the garden with no real work from you other than making sure they have some kind of food and moisture.
If the conditions stay satisfactory for them, their population numbers will rapidly increase without your assistance. You just need to have a spot in the garden bed to be able to feed the worms.
Raise Worms for Their Castings
The more fun way is to start worm farming.
The worm farm can be a simple plastic tote, or two, or three…however many you want and have room for.
You can buy a worm tower or any other commercial worm composting setup.
Or you can build something.
My favorite setup so far is made from 30 gallon plastic drums that we originally built for raised garden beds. But because some of my worm castings had worms when I added them to the garden bed, they started to rapidly increase in numbers within that bed. They were doing so well that we built two more barrel planters for the worms and now have three for worm composting. You can read the article on how to build them here.
There are a lot of options out there that you can explore online and see what fits your lifestyle the best.
Some systems can be stored inside your house. If the bin conditions are maintained correctly, nobody will ever notice it is there. Some people keep the bin in their closet and others might have them in their living room.
Some of the options can be very expensive, but it doesn’t have to be if you are creative.
When worm farming yourself, you will need to harvest (collect) the worm castings from the bins. There are various ways of achieving this, some easier than others and some less time consuming than others. I strongly feel that the method you choose is strictly a personal preference. Try a few different ways yourself and see what method works best for you.
Here are a few ways to harvest worm castings:
Screening
I highly recommend the screening method. When doing this method, try saving yourself some time and leave the worms and cocoons in the sifted castings rather than picking them out and putting them back into the bin.
I recommend this because it does become very time consuming picking them out and it would be best to just give them a new home in your garden and increase their numbers there. Moving the worms out to your garden will allow them to start their wonderful work of improving your garden soil without the extra work on your end.
You can use nearly any kind of screen.
I first started off using a kids play sand sifter. It worked pretty good but I really needed something bigger because the time it took was ridiculous. But hey, it was a start and got me thinking of other ideas.
I measured the holes in that sifter and they were about 1/8″ in size. That is when I found that a metal waste basket had holes about that same size and then I made the worm compost tumbler in the link below for the more advanced worm casting harvester.
Some people say 1/8″ is too small, others say it is fine. I feel that 1/8″ works great when the worm castings are a little on the dryer side.
If the castings have more moisture to them they tend to ball up more and you may want to consider going with something that has a little bit larger holes like the soffit vent in the link below for the simple worm casting harvester.
I wouldn’t go over 1/4″ openings as too much stuff will fall through.
Try different sizes yourself and see what you like. There are all kinds of pre-made metal screens that are inexpensive.
Here are a couple screening harvesters I have made so far, I am sure more ideas will come in the future:
Simple Worm Casting Harvester
The Simple Worm Casting Harvester is a very easy worm casting harvester you can make yourself with some scrap wood you may have on hand (it doesn’t really matter what kind of wood you use as long as it is not pressure treated or treated with chemicals), and one soffit vent you can find at your local home improvement or hardware store for a couple dollars.
More Advanced Worm Casting Harvester
The More Advanced Worm Casting Harvester is a little more advanced worm casting harvester you can make if you are a little handier with a few tools. This one is fairly inexpensive to make. It also contains the mess inside a plastic tote, which is a plus!
The Bright Light Method
You can open up your bin, shine a bright light or let the sun shine in. This will force the worms to move further down into the bin, which then you can grab some worm castings off the top layer. Worms don’t like light.
My experience with this is that the worms don’t move too far down and this can still be a fairly time consuming process, especially if you are trying to not take worms with you.
Another bright light method that I have tried with not very good results (probably because I tend to be impatient) is to dump out all or some of the bin onto a towel or tarp in a sunny or bright location.
With this you will have a mound of worm castings and bedding in a pile. Just like the previous method, the worms will move further into the mound and then you can scrap off the top layer of castings. You may want to have the bin completely or nearly converted over to worm castings so the sorting process goes faster.
Sorting Method
With this method, you simply move all the existing bedding and castings to one side of the worm bin and add new bedding to the other side.
You would put new food on the new bedding side and supposedly the worms would learn that the food is over there and would move there to get to the food.
I have tried this and had no luck whats-so-ever. But give it a try yourself and see if it works for you. My issue could be related to the excessive number of worms in my bins.
Once you harvest the worm castings, what do you do with them?
There are various things you can do with worm castings after you have harvested them. It all depends on what you want to do. Some are quick and easy, others require a slight bit more effort, such as making worm tea.
Seed Starting
They can be used for starting seeds. Use about 1/4 worm castings and 3/4 soil or sand. I wouldn’t use 100% castings, only because that would be a waste of worm castings. It is best to mix it up to save on worm castings even though you can’t add too much since they won’t hurt your plants.
Use as a Soil Conditioner
They can be used as a soil conditioner by sprinkling the castings over the ground and lightly tilling them in. You can apply the worm castings directly next to the plants and they won’t hurt a thing.
Make Worm Tea
You can make worm tea, which is a liquid fertilizer. Take about 1 cup or so of worm castings and mix with about 1 gallon of water and let it sit for a few days.
This liquid contraption can be used as a fertilizer or spray.
When used as a spray, you can spray the leafs of the plants.
Supposedly, this also helps control insects.
Apply to Potted Plants
You can apply them directly to potted plants, indoors or outdoors.
Books I recommend on Worm Composting
Here is a list of books on Worm Composting that I recommend checking out…
Worms Eat My Garbage
This is a great book and I want to say it has nearly everything you need to know on how to start and maintain a worm composting setup.
The Worm Book
This is another good book if you are wanting to learn about worm composting. It does have some very interesting recipes for cooking with worms. Yes, you read that right. Disclosure – I have not and will not try the recipes out of this book!
What Every Gardener Should Know About Earthworms
This book and every book in this series are actually bulletins…approximately 32 page booklets. Short, simple, and for the most part, straight to the point. I have various books from Storey’s Country Wisdom Bulletin Library and find their booklets, or bulletins, useful for a quick read.
Improving Your Soil – Updated and Revised
This is another from Storey’s Country Wisdom Bulletin Library. They have a very short section on earthworms in the garden. As they state, it would be incomplete if earthworms were not mentioned in a gardening book. Even though the section on earthworms is very short, this bulletin is still worth mentioning here.
The Rodale Book of Composting
This book is not just about worm composting, but they do have an entire chapter dedicated to just this. It is a great book on composting in general and lists all kinds of methods of doing so.
Conclusion
There is a lot more information out there than I am able to present here in a single blog post, but I hope it was more than enough to help give you an idea on what vermicomposting is and what the benefits are, along with what might be involved.
If you haven’t tried vermicomposting yet, I highly recommend you do. If not, at least go out to the garden center and see if you can buy some worm castings.