What is it?
Sawdust is the powdery by-product of cutting wood with a saw. Pretty simple really.
What is the primary benefit?
Sawdust is a great source of organic matter for our fertilizer and our soil. Depending on where we live, we may have access to large amounts of sawdust. Where I am right now in Turkey, there are a number of lumber mills near me. Each year I am frustrated by the site of men pouring gasoline on huge piles of sawdust and just burning it off. Remember, Permaculture Principle Six tells us to Produce No Waste! What a great way to repurpose this “waste” product… instead of just burning it.
How is it used?
The first thing to keep in mind before using sawdust, is to make sure that it is well rotted (2-4 years) before incorporating it onto our land or into our compost piles. Just leave piles of it out in the weather, and time will do all the work.
The reason it should be rotted first, is that the process of decomposition of wood binds nitrogen, and nitrogen is needed by our plants. Unless you are using sawdust in a Hugelkultur application, then let it rot first. If you apply sawdust directly to your soil, then watch for nitrogen deficiency (pale green leaves and slowed growth). Add some additional nitrogen fertilizer (Blood Meal would be a good choice) if needed.
Note – Do not use sawdust from chemically treated lumber. Just ask before you collect it!
Add rotted sawdust to your soil or compost directly.
Add fresh sawdust sparingly to established plants or mix 2-3:1 with manure or other nitrogen-rich source (2-3 parts sawdust to 1 part manure).
Add fresh sawdust to an area of land you are planning on improving in the future (2-4 years) and let it rot in place.
If your soil has adequate organic matter levels: 100 lbs per 1,000 square feet
If your soil has medium organic matter levels: 150 lbs per 1,000 square feet
If your soil has low organic matter levels: 250 lbs per 1,000 square feet
NPK Ratio: 0.2-0.0-0.2
A GENERAL NOTE ABOUT FERTILIZERS:
Always test your soil before adding any fertilizers. We can easily damage our plants and the soil by indiscriminately adding soil amendments.