Would 35 year old hardwood sawdust be beneficial to garden ground?
Would adding in the hardwood sawdust raise the nitrogen, or potash.
Certified GKH Gardening Expert
To use the wood as a soil amendment, the wood should be completely composted, with a dark, crumbly and uniform texture with no recognizable pieces of wood or other materials. Fresh wood mulch ties up nitrogen as it starts to decompose, although it will eventually become a source of nitrogen itself, so it should be aged before applying it around shallow-rooted, young plants.