What Medium Can I Pot a Cymbidium In?

Basic Soil Requirements

• Cymbidium orchids need a fertile and moist soil to grow their roots, but the soil must not be alkaline in pH or soggy. Compacted and dense soil, such as clay or heavy loam, aren't good. Coarse aggregates such as pebbles, bark or wood nuggets and compost blended together makes a basic soil for cymbidiums grown outdoors in the ground or in containers in a home or greenhouse. The soil in general should never feel soft.

Potting Mix Types

• A common orchid potting mixture suitable for cymbidiums is one composed of medium-grade fir bark nuggets, peat moss and perlite. You can also use small or fine-sized bark nuggets mixed with 25 percent perlite. Moreover, large bark nuggets also suffice as long as a bit more watering occurs to ensure the coarse mixture never dries out. Personalized blends of pumice or lava rock with peat, sand and perlite are equally as satisfactory for growing cymbidium orchids. Use coconut coir with caution, as it retains lots of moisture and expands, potentially decreasing aeration in potting mixes that already contain small particles.

When to Repot

• Cymbidiums grown in containers require repotting every two to three years. After two years, the various potting mixtures containing bark nuggets and peat decompose enough to create a soft soil profile that tends to retain too much water. Excessively wet soil causes orchid root rot. An indicator for repotting is when the pseudobulbs at the base of the cymbidium begin to spill over or become compacted against the rim of the container. The danger with keeping a large orchid in a small container is that you likely cannot water adequately to sustain the foliage in the small amount of potting mix.

Potting Insight

• The container in which a cymbidium orchid is planted needs to provide about 2 inches of space all around the pseudobulbs. The pot size varies by the size of the clump of pseudobulbs, but choose a sterile container with drainage holes. A heavy or weighted pot with a wide, flat bottom ensures the orchid doesn't easily tip over. When placing fresh potting mix around cymbidium roots in a new container, tamp often. You want a packed soil mix profile, not a loose, movable matrix.