This month we welcomed back an old friend Ray Creek who gave a most interesting talk on successful growing in coconut husk. Ray explained that he first heard of coconut husk as an equine bedding material, but recognised its potential as a growing media for orchids. Coconut husk comes from Sri Lanka and is used in a variety of products based on its fibre, coir. It is important that the material comes from a reputable source, as husk left on a beach to dry is often contaminated with salt. The material sold by Ray is first cleaned by washing, then steam treated to remove any pathogens and finally has nutrients added to it before drying and packaging.
Ray went on to explain the benefits of using coconut husk. It holds a good amount of air within the medium and provides good drainage while retaining enough moisture. The natural pH is between 5.4 and 6.8 which is ideal for most orchids. Nutrients are held by the fibre when at high levels (during feeding) and released later during subsequent waterings. Ray recommends the use of a balanced orchid feed during active growth at every third watering, with plenty of water to flush the medium at other times to prevent the build up of salts. Coconut husk is slow to break down meaning longer periods between repotting. In many cases this can be three years or more.
In the discussion that followed Ray suggested that coconut fibre is ideal for use without additions, but some members found it worked well mixed with bark and sponge rock. Members who use the medium had noted the development of a fine white fungus on the surface of the material, but Ray had not seen this with his plants.
After the talk and discussion there was the opportunity to be tempted by a wide selection of plants from Ray’s nursery, with many members leaving with additions to their collection.