Recycling Sawdust, Wood Chips, and Shavings

Instead of throwing out sawdust, wood chips, and shavings that are produced in your woodshop, there are a number of uses for these materials in and around your home and garden. Here are a few ideas.

Sawdust Mulch

Sawdust can be used as an organic mulch that is very effective at controlling weeds, insulating soil, and conserving soil water. Sawdust can also be used to improve soil quality, especially if it is combined with other organic materials as part of a composting program. Sawdust tends to be acidic and is best used on acid-loving plants such as blueberries, raspberries, strawberries, roses, and rhododendrons. Oak sawdust in particular is quite acidic.

Fresh sawdust tends to form a crust that is impervious to rain water. This can be mitigated by frequently raking the sawdust to break up the crust (no fun) or by combining the sawdust with larger mulching materials such as bark or wood chips. It also helps to apply the sawdust mulch conservatively, generally in a layer no more than a couple inches thick.

Although some people do it, it is not recommended to incorporate sawdust directly into the soil because it has a high carbon-to-nitrogen ratio (300-500:1) and tends to rob soils of plant-available nitrogen. Instead, it is better to first compost the sawdust over time with items high in nitrogen such as grass clippings and then add the "fully-cooked" compost to the soil. The composting also moderates the acid levels in the sawdust. When used as a mulch on top of the soil, nitrogen depletion is less of an issue but be ready to apply the nitrogen fertilizer if your plants turn yellowish-green and grow slowly. Also keep the lime handy.

Many gardeners use sawdust mulch for lining garden walkways. It compacts nicely, keeps the weeds out, and breaks down slowly over time. If placed near grass, sawdust's nitrogen depletion tendencies will help to keep the grass in check so it won't overrun your walkway.

Wood chips and shavings can also be used for mulch or pathways. Compared to sawdust, these materials are less likely to be blown or washed away, or to form a water impermeable surface crust. They make for a long lasting mulch that weathers to a silver-gray color. However, because they are larger, wood chips and shavings will take longer to decompose, and as they decompose, microorganisms use nutrients from the soil that might otherwise be available for plant growth. So, consider mixing wood chips with organic mulching materials like shredded bark before applying around plants.

Note: Sawdust and wood chips from some woods such as walnut and cedar produce phytotoxic (plant-killing) chemicals and should not be used for mulch or compost. The same applies to CCA pressure-treated wood.

Other Uses for Sawdust, Wood Chips, and Shavings

• Use wood shavings for animal bedding. Most fruit woods are safe, as are woods with low aromatic properties such as aspen and poplar. Cedar is not recommended as a bedding material because it emits aromatic hydrocarbons that can contribute to a variety of respiratory diseases in small mammals. Pine can also emit strong odors, but is ok for bedding as long as it is kiln dried. Walnut shavings are toxic to horses and should be avoided.

• Use wood chips for smoking meats and fish. Each type of wood imparts its own unique flavor to foods. Mesquite is probably the strongest flavored wood and has been very popular in recent years. Maple, and fruit woods such as apple, pear or cherry give off a sweet, mild flavor that is good with poultry or ham. Alder has a light flavor and is the traditional wood for smoking Salmon. Hickory adds a strong flavor to meats and goes well with beef and lamb. The same for oak although it's not quite as strong as hickory. Pecan is also somewhat similar to hickory but it imparts a more delicate, subtler flavor.

• Use sawdust for soaking up oil spills. Just sprinkle it on, let it sit for awhile and then sweep up. Sawdust can also be used to clean greasy, oily hands and tools. Sprinkle it on, massage thoroughly, add more sawdust as necessary. Better than using messy newspapers or wasting paper towels.

• Donate your sawdust to schools for use in pottery making classes. Some special firing techniques (e.g, the Raku process) involve packing the pieces in sawdust and firing in a pit.

• Use wood shavings as a packaging material in place of Styrofoam peanuts, bubble wrap, and other synthetic material.

• Heat your woodshop with wood chips. There are wood-burning units on the market that are specially designed to use wood chips or pellets.

• Line the floor of a chicken or turkey coop with sawdust. It can also be used for composting poultry manure.

• Use sawdust for bedding in a worm composter. Mix it in with other bedding materials such as shredded newspaper and cardboard, hopped up straw, seaweed, and compost. Worm composting is a great way to recycle your kitchen wastes year round.