Sawdust mulch has been around since the first leaf fell off the first tree. Leaves and needles rotted and matted together into a protective layer that protected the dirt beneath. The word mulch comes from the German “molsch” translated it means soft or decay. There is also the old English “melsc” rotten hay. By 1650, the noun “molsh” meaning soft appeared in Middle English.
All civilizations have used some form of mulch to control weeds and prevent moisture evaporation. Mulch will trap warmth and halt soil erosion. It will loosen the soil and make a home for earthworms. Mulch also cuts down on garden maintenance. Mulch was used by Greeks and Romans and Egyptians.
Commercial mulch is available at your local garden supply center or you can make your own. There are a lot of materials that can be use. Well-rotted compost, dry grass clipping, and shredded bark add nutrients to the soil. You can also use newspapers, plastic or gravel. Mulch should be 2 to 5 inches thick.
When using sawdust or wood chips as mulch, you must be careful. Both sawdust and wood chips can rob the soil of nitrogen. This causes the soil to become acid. Sawdust also is very compact and decomposes rapidly. Sawdust mulch will have to be applied each season. Blueberries, rhododendrons and acid-loving evergreens do well with sawdust mulch.
It is best not to use fresh sawdust until it has aged six months to a year. This allows it to decompose and break down any nutrients in the wood. Never mix sawdust directly into the soil. Use it around growth where the soil is not loose and apply only a slight amount of sawdust on the surface.
To properly prepare sawdust as mulch, add it to a compost pile also containing manure or fertilizer. The extra nitrogen is needed before mixing the material into the soil. This allows nutrients in the soil to go directly to the plants.