What Is the Best Soil for Growing Orchids?

Bark

• Cheap, lightweight and widely available, orchid bark comes in chunks ranging from the size of a walnut to the size of a pea. Chunks averaging 1 inch in diameter work well for most types of orchids. Bark breaks down with use, however, and must be replaced about every eight months to one year.

Sphagnum Moss

• Spahgnum moss is used for orchids that need above-average moisture, such as paphiopedalums (slipper orchids). It lasts a long time, reducing the need to re-pot. Once it dries out, sphagnum can be difficult to re-wet.

Perlite

• Perlite, a mineral product, is extremely porous, making it both lightweight and a good absorber of water. It does not break down like many organic materials. Its main disadvantage is cost.

Synthetic Products

• Synthetic products for potting orchids include clay marbles, wine corks and even Styrofoam packing peanuts. While they are relatively cheap and readily available, the main drawback to these products is their tendency to dry out too quickly. Orchids potted in them may need watering almost daily.

Considerations

• Orchids in plastic pots with a natural potting material like sphagnum moss will need less frequent watering. Orchids in clay pots with an inert material like clay marbles will need more frequent watering. Beginners kill more orchids by improper watering than by any other mistake.

Expert Insight

• Look for bark sold specifically for growing orchids. Bark sold for mulch may contain harmful contaminants, and can harbor insects.