Worms need a moist environment to thrive. Wood chips don't work well for consistent moisture holding, they can not hold on to water molecules as most of the "accepted" bedding materials can.
Another problem with wood chips is that they will attract fungi and wood rotting bacteria that are not such a good thing for the worms, I don't think either would harm the worms but I also don't think they can eat these particular organisms.
If you had a good source for already decomposing wood chips, these should work fine, the cellulose in them is already being broken into smaller compounds, can both hold and release water quite well.
If you want to do the experiment: regular wood chips in a heap on a known worm harboring bit of soil. a little distance from this heap, put a heap of shredded cardboard or news paper. a little distance from both of these heaps, put a heap of decomposing wood chips.
Water each heap with the same amount of water. Wait five days, turn each heap and note presence or non-presence of worms which would have come up from the ground to inhabit the heap(s).
Record your findings. This experiment should give you loads of quality information on what worms prefer.
I don't do worm composting, so I'm hardly a credible witness on this, but I do use tons and tons of wood chips throughout my food forest. I know that after the chips have begun to break down, they are worm heaven.
So perhaps you could use them as worm bedding after they've spent a year breaking down and composting a bit.
I've seen Youtube videos of people digging in chip piles that are public-accessible (Free Wood Chips -- take all you want!), and those piles that have sat in a pile for 2 years are worm nurseries.
Fresh wood chips = bad bedding. Aged and composted wood chips = good bedding? Maybe keep a few cubic yards of chips off to the side somewhere, and allow them to slowly break down over a couple of season. This could be the pile you pull from for your worm box.
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hau Gilbert, If you want to use the wood chips the fast way to get them breaking down so worms will love them is to soak them in a tub or barrel for about a week then dump them in a pile on the ground.
If you can find some mushrooms in your area, break up the caps and throw those in/ on your soaked pile of wood chips. Some spent coffee grounds in the center of your pile of chips will help them break down too.
The trick is to get those chips breaking down before you use them for worm bedding, once that happens, worms love the bacteria and fungi that are doing the decomposition and they will thrive.
I made several beds around January (Australia temperate zone) under a shaded area with cardboard underneath and woodchip on top followed by a generous layer of moist horse manure and it's September now and so full of worms it aint funny.Different horse's for different course's I would suspect but the woodchip was a very finely ground up and almost fluffy like without huge "Chunks" of wood in it.We have had heaps of rain this year and the chip is full of organisims.....if that's the right term,I'm so happy I'm planting veggies in it already but I do believe the fresh edible vegetable matter is what attracts the worms regardless of the medium it is mixed with.
I've been doing vermiculture for years now and don't hesitate to put wood into my systems. If I had a lot of free woodchips to use as a base bedding instead of my usual paper, I'd put them in a layer at the bottom of the bin, then add kitchen scraps, aggressive regrowing plants pulled from the yard, fresh leaves, coffee grounds, etc. on top. Then I'd put in a handful of worms from an established bin, including a good chunk of the old bedding for temporary food and to seed the bin. (I use closed bins and always have too much liquid once things get going, which is quick.) The worms will find their way around and avoid what's not ready for them, until it is. I'd keep adding kitchen scraps etc. until the level of castings is where I want it, then I'd put the whole thing except maybe a handful of worms and castings into the garden and start over.
If I had a whole bunch of woodchips, I'd still do the above with a few pounds of the chips, leaving the rest outside to age. In Colorado you might need to water the chips for the best effect. Then after some months, when the outside pile is looking dark and tasty, I'd put some or all of the worms and castings on the pile and let the worms get to work.
I think it depends to some extent on the chips. Conifers are slow to break down and, depending how resinous they are, can be nearly water proof. They are not so good at soaking up the liquid.
On the other hand I get lots of loads of chuips delivered here for pathways etc... they spend 6 months or so rotting outside before getting spread usually. After that time they are partially on their way to being hummus anyway, and would likely be better for the worms.
Worst case - try a few batches and see what works. Spending money on bedding materials seems foolish though - they are supposed to be breaking down waste for you, not costing you cash.
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I've been raising redworms for more than 25 years, and this is what I've found. My worms don't really like a bin that's 100% fresh wood chips/sawdust, but I've never had a problem with them accepting used sawdust from my pocket pets (rats) or even a few quarts of unused sawdust, when I just throw it on the top.
I have found that if I have a lot of unused wood chips/sawdust do deal with, I mix it with alfalfa pellets and wet it down. In a few weeks, after the heat up and cool down, it will be much more palatable to the worms.
I've also started bins with as much as 30% sawdust, mixed with other bedding materials (paper, leaves, weeds, coconut coir, etc.) and they have been entirely happy with the situation - meaning that they don't die off and they continue to reproduce. As more organic matter is added to the bin, it slowly breaks down whatever carbon there is (of any kind) and things continue on happily. Also, some sawdust in the bin creates a lighter, fluffier bin with air pockets throughout. The worms like that.