Pine shavings are commonly used as a growing medium. Sawdust has a finer particle size but is sometimes used as well. But the smaller particle size doesn't allow a lot of oxygen to get to the roots. But it has been used. Also you don't to use any from treated wood, or ceder. Not sure about hemlock or spruce.

Hi art3427,

In fact all kinds of wood savings, from bark to rough chips and even finer saw dust are used typically in drip to waste or "semi-hydroponic" culture (only). Special or even standard growing bags (from various materials) are used for the purpose. In your particular case, having access to savings from different particle sizes, I'd in fact mix them and even try various mixes for a first trial. The use of wood savings of any sort is generally disrecommend with any kind of recycling hydroponics, because of the rather quick breakdown of the media. Also (in the case) of finer saw dust, it isn't exactly easy to filter (keep) out of the nutrient solution.

The savings do not need any pretreatment, although it might be a good idea to rinse one time with water. On a more advanced level, you may even consider the extra Potassium you get from the breakdown of wood savings, or even have a glimpse at NPK analyses of various wood types you work with or have access to.

Another option, is to mix wood savings with other natural, but bigger particle sized- perhaps less quickly breaking down media. Like coco peat or peat moss - but yet to be used (as a warm recommendation) exclusively with so called semi hydroponics or with a "drip to waste" technique, where ideally there is only little waste of nutrient solution, btw. Which is in fact a simple, practical and fine - often underrated technique, perhaps because of "too little prestige". ;-)

Good luck with it!

Cheers,
Jean-Luc