Potting Mix for Orchids

Potting Media

• Unlike other houseplants, most orchids --- unless they're terrestrial --- do not obtain nutrients from their potting medium. In orchid culture, the potting media serves primarily as a support system for the plant and nutrients come from fertilizer, which is administered on a weekly basis. Terrestrial orchids are orchids that grow in the ground in the wild and derive nutrients from their humus-rich environment.

What to Look For

• The most important characteristic in a potting medium for orchids is that it be well draining. Overwatering is the most common killer of orchids, according to Dr. Dotty Woodson of the Texas Cooperative Extension. The medium should be coarse, and if it's combined with other media, the entire mixture should also be coarse. Consider the growing conditions and requirements of your particular orchid, as the humidity level will determine how much water the plant receives and also how quickly the media will break down. Of course, it is nearly impossible to tell right away if you've selected the perfect combination, so give your orchid a season to test it out and then decide if you need to adjust the mixture.

Types

• Potting media for orchids come in many types. Bark is a common medium, as are lava rock, coconut husk, sphagnum moss, perlite and even Styrofoam. Orchid potting media come in different sizes, small medium and coarse. If you find that one size isn't ideal for your orchids, it's OK to mix it with media of other sizes.

Feeding and Watering Orchids

• The American Orchid Society recommends that orchids be fertilized "weakly, weekly." Too much fertilizer can cause more foliage growth than flower growth. Remember to dilute the fertilizer before feeding the orchid, as fertilizer is concentrated and can easily burn the roots. According to BeautifulOrchids.com, an online resource, because bark robs the plant of nitrogen as it breaks down, orchids growing in bark will need more nitrogen than either potassium or phosphorous, so take that into consideration when purchasing a fertilizer.