There are three basic types of media for orchids, with variations among each.
- Bark: Bark can come in various grades from fine to coarse. You can also routinely find bark for sale either as pure bark or with additives. In the case of Miracle Gro bark sold commercially in bags, the additive is orchid food. According to the analysis listed on the bag, the fertilizer is 0.17-9.05-0.11, so that is VERY light in the fertilizer department. In the base of Better Gro bark in bags, they have two primary mixes (at least in stock at my source). One is pure coarse “western fir bark nuggets.” The other, which they call their “Special” mix, contains tiny bits of coarse perlite and charcoal along with the fir bark. This blend is supposed to excel in air circulation. I haven’t noticed much difference between the two Better Gro products, but there is definitely a difference between the Miracle Gro all-bark mix and either of the Better Gro products. As you can see in this picture, the Miracle Gro product is much more dense and to my thinking, probably slower drying and with less air circulation.
- Sphagnum moss: Historically I have not used much moss. I always thought of it as a convenient material to use to wrap roots in when transporting (or shipping) orchids. I have frequently purchased orchids that cam delivered in moss. I generally used a finer grade of bark for orchids that needed to be kept more routinely moist. However, with some recent revelations from email conversations with one of my favorite orchid vendors (Fantasy Orchids, located in Louisville, CO, found at http://www.fantasyorchids.com) I’ve recently developed a new appreciation for sphagnum moss and have begun to use it as the regular potting material for my Phragmipediums, which need to be kept routinely from drying out completely. The moss seems to not compact as much as the fine bark I used to use, which means it should provide better air circulation as well as moisture and humidity – the ideal combination for Phrag. roots. Better Gro also supplies the Sphagnum moss that’s available to me locally.
- Air. I obviously can’t provide pictures of air. But some orchids grow in it. Vandas, for example, are routinely grown in wooden baskets where the roots grow down through the slats and hang in the air. They require higher humidity and regular misting or spraying. I have a new way of growing Vandas that’s a lot less elegant, but MUCH easier as far as I’m concerned. See the listing for Vandas for details. Other orchids are grown wired to bark. Similar to Vandas, they need regular spraying and higher than normal humidity to do well. These have historically been considered the harder orchids to keep in the home simply because a) they require higher humidity than we generally want in our homes and b) they require more regular care in the form of misting, which has to be done much more frequently than the typical watering regimen that’s suitable for most other orchids. Obviously if you have a personal greenhouse, you have more options in terms of controlling the environment provided for your orchids.
- Soil. There are occasional orchids that actually grow in soil. I have one, a Ludisia discolor. It is planted in light, humus-rich soil and is watered regularly (but not left standing in water). There are other orchids similar to this, frequently referred to as “terrestrial” orchids, or “ground” orchids.
- There are other materials. Coconut husks are available on line. I used coconut husks when I had them to pot up my Cymbidiums because they stayed outdoors for six months of the year and so were subject to not only regular waterings with everything else outdoors, but routine rainfall as well. Coconut husks are particularly durable. They take a LONG time to break down, much longer than fir bark. Other orchid supply companies sell all sorts of what I call “personalized” media, consisting of their own unique (proprietary?) combinations of moss, “sponge rock”, charcoal, bark, perlite, styrofoam, or any number of other ingredients. It’s up to you if you wish to source and try any of these more unique combinations.