Is Planting Orchids in Bark or Cinder Best?

Bark

• Bark used for orchids is either fir or redwood. The bark is cut up or shredded, cleaned and sterilized. After processing, it is categorized according to the size of the bark chunks into small, medium or large grades. The best grade of bark to use is determined by the size of the orchid. Vandas and large cattleyas, for example, have big roots. Large-grade bark is best for them. Miniature cattleyas and phalaenopsis grow best in medium-grade bark. Use small or fine-grade bark for oncidiums and paphiopedilums, which have small roots. Different grades may also be mixed together to adjust the texture of the growing medium.Give orchids planted in bark a high nitrogen fertilizer, a 30-10-10 formula for example, as bark uses up available nitrogen as it decays. Bark breaks down and must be replaced every year or two.

Charcoal

• Cinder or charcoal is also available in fine, medium and large grades or sizes. It is most often used for orchids as part of a potting medium mix. The charcoal has a sweetening effect on highly acidic bark, helping to maintain a less acidic pH. Large-grade charcoal is used alone in baskets for orchids like Vandas.

Coconut Husk

• Coconut husk is another good option that has been gaining in popularity. It is available in shredded form and small, medium or large chips. It can be used in the same manner as bark. Coconut husk fiber is used in baskets for Vanda orchids. Coconut husk material is extremely porous and retains moisture well. Coconut husk fiber and chips take years to break down, making them a longer-lasting option than bark.

Other Ingredients

• Lava rock, perlite or sponge rock and pumice are often added into orchid potting mediums. Catteleya orchids grow well in a mixture of two parts large bark, one part medium bark, one part large charcoal and one part perlite. A good mix for Dendrobium orchids contains one part each medium and large bark, one part lava rock or large pumice and a half part charcoal. A good general mix for orchids contains two parts fine bark, six parts medium bark, four parts perlite and one part charcoal.

  Different orchids have different preferences in growing mediums. The climate can also have an effect on how well an orchid does in one medium or another. Some experimentation may be necessary to determine which growing medium works best for a particular orchid.