The outer layer of buckwheat seeds, these lightweight hulls—which measure just 1 millimeter in diameter—make for a finely textured, dark brown mulch that works especially well around rose bushes. It's also recommended for use in smaller beds or container gardens, and should be applied in a layer no more than 1 ½
inches thick. To keep the tiny hulls from blowing away, sprinkle them lightly with water on a regular basis.
Buckwheat Hulls, from The Birkett Mills, $12.90 per bag (2 cu. ft.).