One of the questions I often get about the Worm Sifter is how does it work with wet clumpy material. The answer is it doesn’t work well with wet material. If the castings and bedding are wet they stick together and will not sift very well at all. It is important that when you sift that the material is dry enough to crumble and fall through the 1/8 inch holes in the sifting screen.

moisture meter

general purpose moisture meter

If you have an indoor worm farm operation you stand a much better chance of controlling the moisture than if you have an outside operation. The maximum recommended moisture level is 85%. A worm breathes through its skin and it will suffocate if it is too dry, below 60% from what I have been told. If your moisture content is too high your material won’t sift properly and if it is too low your worms cannot breath.


double handful of worm poop

Sifted Castings are Crumbly and loose

It’s hard to tell from pictures and experience is the best teacher. This is about what your castings should look like when you are done sifting the worms and eggs out. Get yourself a moisture meter and measure the moisture range of castings that work well and those that don’t work well. Once you get a feel for it you won’t forget.


Too dry worms die, Too wet you won’t forget.

A good rule of thumb on testing for moisture without using a moisture meter is the “Squeeze Test”. Grab a handful of your bedding/feed mix and squeeze it as hard as you can. (with no worms in it.) If you can get more than one or two drops of water out of it, it is too wet.

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