Can I use sawdust in my garden?
What can I do with oak, cherry, maple, and poplar chips from my dust collector? Can I use them as flower garden bedding material or mulch? I think this would be great on flower beds, as it would decompose quickly and add nutrients to the soil, but I'm not sure.
—Jim Shipman, Boonville, Ind.
We ran the idea by Garden Ideas and Outdoor Living editor Luke Miller, who didn't recommend sawdust as a bedding material, Jim. Instead of adding nutrients, the fungi and soil bacteria that break down the sawdust extract nitrogen from the soil that your plants need to thrive, sometimes turning them yellow.
Instead of using sawdust straight from the collector, create a compost pile where the wood chips can be mixed with grass clippings and other yard waste. That allows the sawdust to break down and turn into mulch, rich with the nutrients and microbes plants need.
The wood species you mention will convert to compost, but avoid sawdust from walnut, hickory, and Ailanthus (such as Chinese sumac), as well as any pressure-treated lumber, MDF, and particleboard. These contain natural or synthetic chemicals that impede plant growth.