The 411 On Separating Worms From Castings

Written by Jo Lynch on March 24th, 2015

A worm’s value can be equated to what their castings are being used for.  Worm castings could be coined as a gardener’s “black gold” and is one of natures most potent fertilizers.  When composting with worms it is always prudent to maintain the bedding in which the worms are living.  By separating the worms from the castings not only are you gathering this fertilizer for use in the garden or flower bed, but at the same time you can place the worms in fresh bedding.  Keeping the worms in fresh bedding is a key element to their health and productivity.  The tricky part is how to separate the worms from the castings and this can be accomplished in many different ways, but today we will focus on what I have found to be the top three methods.

  1. Screening:
    • This method is exactly as it sounds, using screens to separate the worms and the castings.  This method is very effective and is the quickest way out of our three methods.  In order to perform this method you will need a tub of worms, a 1/4 inch hand screen (Currently being sold on our website, check it out!), and at least two empty worm tubs.  Start by placing the tub of worms and the two empty tubs side by side on a work table.  Now it seems to work better if you mix your worms and the castings up a little by hand in the tub before proceeding.  Then take the hand screen and place it on top of the empty tubs, and scoop about two handfuls of worms and castings onto the hand screen.  Now shake the screen side to side over the middle empty tub, thus having your castings drop into this tub.  Once the worms are relatively clean, empty them out of the hand screen in the remaining empty tub.  Repeat this process until you have fully separated all the worms and castings (Note: there may be a few smaller worms that slip through the screen in with the castings, you may want to collect them or you can leave them depending on what the castings may be used for).  Now you should have a tub of castings and a tub of clean worms, be sure to immediately re-bed your worms in fresh bedding in order to maintain their health and productivity.  Besides the 1/4 inch screen, there also is a 1/8 inch screen available to separate worm eggs from the castings, this is accomplished by using the same method above using the castings just collected.                                                                                                                                                                                                 
  2. Light:
    • Using light is also a very effective at separating worms from castings.  This a more simple method, but takes a little more time and care.  To perform this method take your tub of worms and place them underneath direct light (Note: this can be artificial light or sunlight).  Worms are sensitive when it comes to any form of light and instinctively move deeper depending on how intense the light may be.  Once you decide your light source, place the worms there and using your hands gently clear the top layer of bedding and castings into an empty tub exposing the worms underneath (Note: if using sunlight, take care that the worms are not left for long periods of time causing overheating of the worms).  Repeat this process, driving the worms deeper and deeper until they are gathered at the bottom of the tub and you have the majority of the castings in another tub.  Immediately re-bed your worms in fresh bedding, this can’t be stressed enough.
  3. Migration:
    • This method isn’t just for the birds, but it is simple to perform.  To perform this method take your tub of worms and place food on one side of the tub and then you just simply wait.  How long you wait varies depending on the concentration of worms that may be in the tub and how hungry they may be.  A rule of thumb on when they may have migrated to where you want them to go, is watching for the food to be cleared from the top of the bedding.  It may actually take more than one feeding in this manner to draw the majority of the worms to the side that you want them to be.  The worms will migrate to the side that has the food, clearing the other side and allowing for you to collect castings from that side. This method works well, but may not be as effective as our first two methods.  After the removal of the castings, just add enough fresh bedding to the tub to replace the amount of castings that were gathered.

Now that we have discussed these three methods, go get some “black gold” and grow those gardens! 


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