Decisions, decisions, your orchids need to be repotted and you may be confused as to what to use for potting material. There are numerous types of material that you can use for potting orchids. Come along let's get familiar with them.
    Potting orchids is very different than potting ordinary houseplants. Repotting a houseplant is fairly straightforward. You simply take the plant out of its pot, place it in a new larger pot and add dirt. With orchids, however, you don't normally use potting soil. What you use for orchid potting medium depends primarily on the type of orchid and how you are growing it -- in a pot or mounted.
   I do have to stress that you never want to repot your entire collection into a new type of medium until you try it for a while to see how your orchids adjust to it.
   Just because your neighbors' orchids may do well in a medium that does not mean yours will do well also. This is because there are other factors involved such as you may water more often, or have different types of orchids.
   When using a new type of medium, repot only a few different types and see how they react to the new media.
   Remember, most orchids are in a pot for YOUR BENEFIT not THEIRS! They would be happy growing in the trees and letting their roots hang free in the wind. If you are going to confine your orchid to a pot, you should give them something that will make it happy.

FIR OR REDWOOD BARK
   Fir and redwood bark has been the most popular medium for orchids for many years. This type of bark is NOT the common "yard bark" you find in the garden shops which is mostly made from pine! Because the cost of potting bark gets higher every year, growers are looking for new less expensive mediums for their orchids.
   Potting bark has been washed, sterilized, treated for weeds, and graded for size. The bark is available in three different grades: large, medium and small. The large size bark is good for large-rooted orchids such as Vandas and large Cattleyas.
   The medium size bark is used for medium sized plants such as miniature Cattleyas, Odontoglossums, and Phalaenopsis.
   The fine size bark can be used for your fine rooted orchids like the Oncidiums and the ones that like to be moist like Paphiopedilums. Many people like to mix charcoal and perlite with the bark.
   It is also a good idea to soak the bark for a day before you use it to help it absorb water and to remove any of the fine dust particles. Growing orchids in bark requires you to use a high nitrogen fertilizer such as 30-10-10.
SPHAGNUM MOSS
   If you live in an area where Sphagnum moss grows, you are very lucky. If you are able to collect it live, it should survive in your orchid pots and your orchids will also like it.
   Do not pack it in the pot, leave it loose around the roots. This type of moss is typically used as a base for mounting orchids onto pieces of wood, or other mounting material.
  You can buy dried Sphagnum moss in long fiber or short fiber types. I personally use the long fiber. New Zealand Sphagnum moss has been used all over the world and is known to be about the best there is for orchids. Sphagnum moss can hold up to 10 times its weight in water, so be careful with your watering and don't over water. If you tend to "overwater" don't use this media. Orchids that like to be moist do very well in this, such as Miltonias, Paphiopedilums, Odontoglossums and Phalaenopsis. Sphagnum moss is also excellent to use on seedlings because it contains a natural antiseptic that helps stop "damping off" fungus disease.
   Do not use the green dyed florist sheet moss. That is not Sphagnum moss!
CAUTION: When handling Sphagnum moss you should always use gloves. Sphagnum moss can contain a fungus that can effect some people. It is quite rare, but caution should be used when handling it.

PERLITE
   Perlite is a heated natural mineral, and is often used as an additive in potting soil to help retain moisture and give an airy texture to the soil. It is also used to mix with many of the potting mediums for orchids. I use it with my bark, which helps hold a little more moisture. Some growers even use it alone with great success.
   There are orchid lowers who grow their Phalaenopsis in straight perlite with great success. In that case uses 1/8" screened perlite.
   Some of the advantages of perlite is it does not rot, therefore thrips or fungus gnats will not infest the medium. All epiphytes that can be grown in bark can be grown in perlite.
   You can buy different grades of perlite from very fine to coarse.

CHARCOAL
   No, this is not the compressed, "briquette" type charcoal that you use in your barbecue.
Charcoal helps to keep the mediums sweet and keeps them from souring.
   You can buy charcoal in large and fine grades. The large grade is excellent to mix with the large or medium bark. It can also be used alone in the slotted baskets that some orchids are grown in such as Vandas. The fine charcoal is used in the peat mixes and the fine grade bark. It can be used with any of the media mixes.

TREE FERN
   Do you tend to overwater? If so, this is the medium for you!
This medium lasts a very long time and the orchids like the airy mix. Some growers, however, do not like to use tree fern because it is hard to use.
   Tree fern is a stiff fiber and is not easy to put in pots around root, but once you have your orchid potted it is excellent. Slabs of tree fern are an excellent base for mounting orchids.
  The roots grow right into it anchoring the orchid to the material. If you live where the temperatures are warm and it is very humid this is excellent to use.