Posted: 03/03/2015 at 04:04
Will worms digest sawdust?
The short answer to this question is no. Worms do not possess the
digestive capability to process (and derive nutrients from)
materials such as woodchips and sawdust.
Pure sawdust has an extremely high C:N ratio. It has an
extremely resistant structure - made up of cellulose, hemicellulose
and lignin, the compounds responsible for the strength and
structural integrity of woody plants (just look at trees)
Woody wastes tends to be broken down very slowly over
time, primarily by fungi. This is not to say that you can't make
sawdust and woodchips more worm-friendly and then use it as a
food source. Some extra steps will be necessary.
If I wanted to use some sawdust in my worm systems I would first
mix it with something rich in nitrogen - farm animal manure would
be a great choice - then let it sit for at least a few months to
encourage some rotting. large hot composting piles will help.
Another opertinity is to use the sawdust to
grow edible mushrooms, such as Shitake or Oyster mushrooms, which
actually rely on woody materials for their nutrition. Then when
your crop has finished fruiting you can mix the spent substrate
(which will be full of fungal mycelium) with other worm foods,
such as manure or food scraps, and start feeding it to your
Wood digesting fungi such as these have specialized enzymes which
aid in breaking down the resistant structure of woody materials,
rendering them more prone to attack by other microorganisms.
Woodchips and saw dust can't soak up moisture the way paper and
cardboard can, so apart from offering little nutrition they can't
even be used as an inert bedding material (unless well rotted and
mixed with other materials).
Something else to keep in mind if you are thinking about using
sawdust or woodchips in your worm beds - even if you do mix them
with manure etc and allow them to rot, you are almost certainly
going to be left with some woody debris in your vermicompost.
For the casual hobby vermicomposter this certainly isn't a big
deal, but for someone who is keen to sell their castings this
might be an important consideration since your final product may
not look as finished as you would like it to (even if it may still
be an excellent compost).