Sawdust uses

Various idaes for putting wood waste to use. March 20, 2001

What can sawdust be used for?

Forum Responses
I mix it with dirt and chicken manure for compost in my garden. Any excess goes on the pine plantation. Other farmers use it in chicken pens, cow pens, horse stalls, etc, with the ultimate destination being the fields. Commercially it is used as mulch and compressed into fire logs for heating. The pulp mills (paper) use it under air pressure for immediate heat in the furnace for the boilers. They call it "white dynamite." There are a multitude of commercial uses, from pressboard to insulation.

You didn't mention what type of wood this sawdust is coming from. Some sawdust is bad for animals and plants.

Almost all sawdust in the US is used for energy production.

Gene Wengert, forum technical advisor

I've seen red oak sawdust used on blueberry plants. The acid helps the plants produce. We burn most of ours in the boiler to make the steam to dry wood.

Humus, the product of decayed wood, gives soil nutrition and structure, which is important to plant health. If soil is gloppy, it does not provide a plant's roots with the air they need for proper absorption of nutrients.

I do not know of any woods which are toxic after they have been adequately decomposed, as most of the toxins in these woods will break down in the presence of detritovours (sp?). Give old wood back to the earth, so that it can give life to new trees for more wood.

Caution: Walnut, when put back into the soil, acts as an herbicide. There are other woods with similar properties, including insecticide activity.

The bacteria decomposing any type of wood will tie up all the nitrogen, and any plants present will have the "yellows," unless you add substantial amounts of nitrogen. (This is one reason why using wood for animal bedding before spreading is a good idea.) Fine sawdust is the worst for tying up nitrogen; big hunks are not so bad.

Also, if you add lots of sawdust, you are adding trace amounts of various elements, including some heavy metals. If you add too much wood, you will increase the concentration of these heavy metals above "safe" levels. The forest does the same things, albeit much more slowly and not as concentrated. I believe that in some states you must have a permit to spread wood and/or wood ash on agricultural fields.

Be careful when using wood as a soil amendment.

Gene Wengert, forum technical advisor

Juglone is the stuff in walnut that is repulsive to some plants. Corn is not bothered by it, and walnut husks (which have a much greater intensity of juglone than walnut wood does) have been used as a natural herbicide in cornfields. Juglone breaks down within a few years, so you can put it in a longer rotation pile.

A company in my area started grinding stumps into mulch to use for landscaping. The EPA shut them down, saying that, other than the human body, the second biggest collector of heavy metals was tree stumps.

Comment from contributor A:
Most timbers probably provide good compost for the soil, but what if there is MDF dust mixed with it? Same issue with sawdust use with animals. Also, I appreciate that most wood shavings are okay with animals, but what about fine dust - if it's dangerous to humans, surely it's dangerous to animals also.

Wonder if there is an efficient and cheap compacting machine out there so that summer waste can be reduced in size, handled and stacked in blocks and burnt for fuel in winter?