WHAT IS WOOD FIBER? Wood fiber is produced by fiberizing unprocessed wood under high mechanical pressure at a high temperature. This high temperature is important for obtaining wood fiber free from plant diseases. Wood fiber is used by MeeGaa Substrates as an additive in substrates. With wood fiber in the substrate we obtain a more open structure which improves the drainage. Wood fiber is an important raw material that makes the structure of a potting soil mixture lighter, so that this raw material has a positive influence on the root development of the plant in the substrate.