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I feel that one of the easiest ways to collect the worm castings is with the use of a harvester. It is quick and easy to use. It is easy to collect all these worm castings and it keeps all the big stuff separated.
I have tried to separate the castings from the worms with very little success. I felt that the method of placing the worms and castings in piles under a bright light, such as the sun, was a very inefficient method. The worms don’t move that fast and there is still bedding and food in the way.
I found there was no easy way of separating the castings from the worms, the bedding, and the food that was not yet broken down by the worms. Everything took time, time that I would rather use having fun or for getting other things done.
I wanted something simple to make, very low cost, very easy to use, and contains the mess. This system does all that!
Doing a bunch of research online, I found the trommel systems. Those seemed to make a lot of sense to me, but they all seemed to require a lot of work to make. Some looked flimsy. Others looked like they would make a mess since there was no way to contain the castings.
For the first couple times of filtering the castings, I used our kids sand sifter from their sandbox. It worked great but was a very slow process. But, the holes were only about an ⅛ inch in size and separated the castings nicely.
Doing some more thinking, I thought about what what might have that same size holes. ⅛” hardware cloth! Wait a minute…that stuff is not cheap!!
Back to the thinking board…a metal mesh wastebasket…what size holes might they have? Sure enough, they are about ⅛ inch as well!
The wastebaskets are cheap!
I was later shown one other design that incorporated a wastebasket. This one was okay, but it did not contain the castings.
Now, some experienced worm farmers might say that the ⅛ inch holes are too small. For me, this size works just fine. Try it out, see what works for you.
The next problem I wanted to solve was on how to keep all those castings in one spot while rotating the wastebasket.
My wife, Joy, thought of a plastic tote. Brilliant! Problem solved!
I did come across one other design online that used a plastic tote, but the basket design was not as simple.
One more problem…how do I incorporate the wastebasket with the plastic tote?
Well, I needed something to allow the wastebasket to spin on. The only thing I thought of at the time was a threaded rod that I could screw a wooden lid on. This threaded rod went all the way through and rested on the top of the plastic tote.
This worked okay, but it was a pain to open the lid! The nuts would occasionally come loose, and the threaded rod would catch on the plastic tote. I needed something smooth for it to spin on, rather than the threads spinning on the edge of the plastic tote, which would pull it one way or another…causing more issues.
My father-in-law and I were talking about how to improve this system. I wanted to be able to remove the lid easily and not have the spinning get caught on anything. He thought of using the coupling nuts on the inside of the wastebasket that I could then screw into through the lid. This solved everything for me. Now to implement it!
The next day, Joy talked me into going to Lowes and buy some supplies. The whole thing was assembled within an hour the following day. Mind you, I already had the lid and wastebasket made.
Here is a complete list of supplies you will need to make this worm casting harvester:
- (1) Plastic tote – approximately 13” wide, 20” long, 15” high
- (1) ⅜” x 10¾” long threaded rod (verify the length with your wastebasket)
- (2) ⅜” coupling nuts
- (1) ⅜” x 6” eye bolt
- (1) ⅜” x 2½” bolt
- (8) ⅜” nuts
- (6) ⅜” washers (mine are a little bigger, but was what I had on hand)
- (1) wire mesh wastebasket
- (1) fence board, cut down to:
- (1) 16¼”
- (2) 12”
- (1) 12” (for the lid – verify actual size with your wastebasket)
- (1) ⅜” plywood (12” square – verify actual size with your wastebasket)
- (4) 1⅝” drywall screws
The whole cost of this system was very affordable and I feel that just about anybody can make it.
The castings end up beautiful!
Check out my video here for some step by step instructions on how to make it:
Let me know if you have any questions on this and I will be more than happy to answer.
What about the cacoons? Cacoons typically fall through with the castings, how do you seperate them?
Hi Rexx! Good question. That is one that comes up a lot on some of the vermicomposting Facebook groups I am on. I have not tried keeping the cocoons separated from the castings, but everyone who answers this question seem to state to use no larger than 1/8″ mesh. The mesh on this trash bin is approximately 1/8″. It does hold some back, but there are still some that make it through. Honestly, since I don’t sell my worm castings, I never worry about the cocoons passing through. I am fine with having the worms populate the areas I put the worm castings giving them a new home.
If you go with a mesh any smaller than 1/8″, you will have to have some pretty dry castings in order for them to flow through. I feel that this would really depend on the type of vermicompost system you have that would allow this. When the castings are moist, they tend to stick together and ball up.
You could try:
1. I have also read about people sifting their castings and let the sifted casting sit around for 6 weeks or so. This should allow time for the cocoons to hatch. From there, you can sift again and try to get the new worms out. I don’t know how effective this is as I would assume most of these baby worms could still make it through the holes just like pot worms and other baby worms do when ever I sift.
2. I suppose you could also sift the castings, let them sit the 6 or so weeks, and then give those newly hatched worms a food source away from those castings so they migrate over and away from the sifted castings giving you castings that are mostly free of cocoons and worms. This might be your best bet.