With temperatures rising and spring in the air, you may be looking forward to harvesting some of the contents of your worm bin. Worm castings are perfect for giving new plants a great start, but how do you separate those hard-working worms from their castings?
Well, if you have a multi-level worm bin and have been adding new food scraps to the top bin, then you’ll find the most castings–and the fewest worms–in the bottom bin.
But what if your worm bin doesn’t have more than one level? Well, there are several ways you can sort your red wigglers from their castings.
Sorting Worms With Food
Sorting with food is one of the slowest methods, but also one of the easiest. To sort with food, you simply feed your red wigglers in one corner of the bin for a few weeks. Over time, the worms will congregate around their food source and then you can harvest castings from elsewhere in the bin. Place new bedding in the empty part of the bin or spread out the remaining castings and worms, and you’re ready to go.
If you don’t want to wait for the worms to gravitate to their food, then you can use light to sort your worms.
Sorting Worms With Light
Sorting with light is faster than sorting with food, but it does take some consistent attention. Worms will naturally move away from light, but too much light can cause your worms to dry out.
To use the volcano or mound method of light sorting, first dump the contents of the worm bin onto a stable surface and mound it up. Then place some new bedding and food scraps in the bin, ready for your worms when you’re all done sorting.
In a few moments, the worms will burrow down into the pile and you can harvest the other materials from the surface. Place those surface materials in a separate container and allow the worms to continue burrowing away from the light before you harvest the next layer. Place the worms and remaining materials back in the bin.
Alternatively, you can use burlap to separate your worms. First, gently remove the contents of your worm bin. Place them in a temporary location and then put some new bedding and food scraps in the emptied worm bin. Put a piece of burlap (or other material with worm-sized holes) over the top of the new worm bin material. Then place a one- or two-inch layer of the unsorted material on top. Place a light above the worm bin, but not close enough to heat it up. In about 20 minutes, your worms will migrate away from the light and you can use the burlap to move the remaining material off the worm bin.
Using a Sifter to Sort Your Worms
If you need finer worm castings, you may wish to use a compost screen to separate them from the rest of the worm bin contents. To use a compost screen, you simply place the sifter screen over a wheelbarrow or other large container. Then put some of the worm bin contents on the screen and shake it until the worm castings fall through, leaving the worms and unprocessed compost on the top.
Sorting Your Worms by Hand
Hand sorting is one of the simplest of all sorting methods. If you just need a few handfuls of castings and don’t mind handling your worms, this may be the best method for you. Simply scoop out a small amount of material and sort through it by hand—returning worms to the bin and setting aside castings for your use.
No matter how you sort your worm castings, do not worry too much if a few worms end up in the compost. If the castings are excessively muddy, you can expose them to the air for a day or two to help dry them out. Store your “black gold” in a bag or bucket, keeping them moist and protecting them from heat until you are ready to use them.