One of our goals as an urban sawmill is to use as much of a tree as possible, so we are very happy when sawdust is put to good use.  We produce a lot of excess sawdust and almost always have it available to the public at no cost.  Here are some great ways to use it and some info to keep in mind for your sawdust adventures.

Chemical Free

Whether you are using sawdust for compost or for your fancy hamster, you will want to make sure the wood it came from has not been weatherproofed or pressure treated. An easy way to tell if you aren't sure is by examining the color, the chemicals are a transparent grey-green. If you come across sawdust made from this material make sure you dispose of it properly, it should never be dumped outdoors. 

Black Walnut

You're probably familiar with the warning label on snacks, "Produced in the same factory as peanuts". You should keep this same warning in mind when using sawdust from a facility that works with Black Walnut. While it is a beautiful material with a distinct dark color,  it contains a compound called juglone, which stunts growth and can kill plants and animals. It can be used to this compounds advantage to kill weeds in sidewalk cracks or to contain plants to a certain area. Black Walnut can be used in a compost because as it decomposes juglone neutralizes.

Tim and a Black Walnut sawdust pile

Compost and Garden Beds

Compost is a great option for getting rid of sawdust because it returns the material to the earth and produces a mineral-rich compost. Fresh sawdust is acidic, it takes about a year to decompose and neutralize the harsh stuff before using it in the garden. Nitrogen-rich material or "green" material like grass clippings and kitchen waste makes up the majority of a compost mixture. The "brown" material, like sawdust or dead leaves, will add carbon and balance the nitrogen. You can compost all year long, even in winter because as your compost breaks down it makes it's own heat.

The fact that the decomposition process creates heat opens up another interesting composting opportunity.  You can leverage this reaction to hot water and create methane gas.  The underrated Frenchman, Jean Pain, is a pioneer in this technique.  By circling pipe through a compacted, well planned and maintained compost pile, you can transfer the compost heat into water or antifreeze to use in your home.  A simple system could pump water through the pipe and would come out warm on the other side.  A more permanent system could pump an anti-freeze like glycol in a loop between the compost and a boiler to heat the water in the boiler. 

Sawdust can also be used as mulch or on pathways in the garden and yard.

ABSORPTION

Sawdust can be used as a cleaning agent when a rag or sponge isn't up to the task. This is why Katz Deli keeps a layer of sawdust on their bathroom floor! Where else can you use the stuff?

• Kitty Litter: This is a great alternative to kitty litter because it's economical and non-toxic, it doesn't clump but is easy clean up.
• Oil Spills: Oil spills are unseemly on the garage floor, but are also hazardous to living things. Sprinkle sawdust on the spill and let absorb for several minutes. Shovel into a seal-able bag and dispose of in accordance with your city.
• Old Paint: Trying to dispose of old latex paint can be a pain because it takes so long to dry, sawdust can expedite the drying process. In a dry and well-ventilated space, seal a cardboard box with packing tape then dump 6? of sawdust in the bottom before pouring in the old paint. Stir up then repeat, add more sawdust then more paint. Let dry completely before tossing.

Stove Heating

Have a pellet stove?  Why not make your own pellets with excess sawdust!  Small scale wood pellet mills are affordable coming in around $2000 and can produce over 200lbs of pellets an hour.