Wood fiber in pot plant culture; peat replacement up to 50% in volume?

Use of peat and coir in horticulture is under pressure because of the negative effects on the environment. Peat harvesting releases CO₂ into the atmosphere and changes the wetland ecosystem. Coir production can cause salt pollution in the country of origin as the product has a high salt level and is washed with fresh water before use as a substrate. HydraFiber, a specific wood fiber product was tested as substitute for (part of) peat and coir in professional potting soils. Wood fiber was mixed in 3 volume percentage ratios (30, 40 and 50% v v^‑1) with peat or coir. Nutrient content and stability were used to calculate appropriate fertiliser levels for each mixture for growth of a begonia crop in an ebb and flood system. Addition of up to 50% v v^‑1 wood fiber to peat or coir has no negative effect on the rate of development to flowering of a 10 week crop. The ratio of weight/length of the plants is similar for all treatments. Addition of 40% and 50% v v^‑1 wood fiber to peat reduces water content by 16% v v^‑1 and increases air content by the same amount in the substrate in the range of -6 to -100 cm pressure head. Addition of wood fiber to coir has a similar effect. A lower average water content in substrate mixes of peat and wood fiber indicates it is more difficult to overirrigate but that it also requires a more precise monitoring of both, water content and nutrient status. It also requires a higher frequency of irrigation and more frequent adaptations of the nutrient level in the water supply. Using wood fiber in percentages from 30 to 50% v v^‑1 may also require an adaptation in the growing medium used for propagation plugs.