Cymbidium orchids, commonly referred to as boat orchids, are known for their semi-terrestrial nature. They develop dense, fleshy root systems that require periodic attention. Due to their vigorous growth and the eventual breakdown of potting material, repotting is necessary to maintain plant health and encourage future blooms.
Optimal Timing and Preparation
The decision to repot a Cymbidium is driven by the condition of the potting media and the size of the plant. A mix that has degraded over two to three years will no longer provide necessary air circulation, increasing the risk of root rot. Signs of decomposition include water pooling on the surface or a sour smell emanating from the pot.
The ideal time for this procedure is immediately after the plant has finished flowering, typically in late winter or early spring. Repotting during this period minimizes stress, as the plant is preparing to put out new roots and pseudobulbs. Repot when the plant is severely root-bound, with pseudobulbs pressing against the pot edge and new shoots having no room to develop.
Essential Supplies and Potting Media
Cymbidiums thrive in a finer, heavier, and more moisture-retentive mix than epiphytic varieties. A suitable potting medium must drain quickly while still retaining moisture and providing air pockets for the thick, fleshy roots. Common components include:
- Medium-grade fir bark.
- Perlite.
- Coir (coconut fiber).
- Peat moss.
- Charcoal.
The new container should only be one size larger than the old one, providing enough space for two to three years of growth. This usually means an increase of two to four inches in diameter. A pot with excellent drainage holes is necessary to prevent the roots from sitting in saturated conditions. Before starting, sterilize all cutting tools, such as shears or a knife, by wiping with rubbing alcohol or a flame to prevent disease transmission.
Step-by-Step Repotting Procedure
Gently remove the orchid from its current container, which may require tapping the pot edges or cutting the pot away if the roots are severely bound. Once free, carefully shake or hose away the old, degraded potting media from the root ball. Remove as much of the old mix as possible, as this material holds excess moisture and contributes to rot.
Inspect the root system thoroughly, identifying and trimming any roots that are dark, mushy, or hollow using sterile tools. Leave only the firm, white or light-colored healthy roots. If the plant is very large, you may divide it, ensuring each new division retains at least three to five healthy pseudobulbs. Separate divisions by cutting the rhizome connecting the pseudobulbs or by gently pulling the sections apart at their natural weak points.
To position the plant, place a layer of fresh media in the new pot, creating a slight cone in the center. Situate the plant so the oldest pseudobulbs are nearest the pot rim, allowing new growth to develop toward the center of the container. This placement gives new shoots maximum room to mature before the next repotting is required.
Fill the remaining space with the fresh potting mix, working it carefully among the roots to eliminate large air pockets. Gently tap the pot or press the mix to firm the media around the roots, ensuring the plant is stable and stands upright. The base of the pseudobulbs should sit at or just above the surface of the new media.
Post-Repotting Care and Recovery
After the trauma of repotting and root trimming, the plant requires a brief recovery period to heal damaged tissue. Withhold the first thorough watering for three to seven days, allowing root wounds to callous over and preventing the entry of pathogens. During this time, the plant can be misted lightly to maintain humidity around the leaves.
The newly repotted Cymbidium should be placed in a slightly shadier spot with reduced light intensity for one to two weeks. Suspend fertilization, as the plant needs to establish new roots before it can efficiently absorb nutrients. Resume a regular watering schedule and begin feeding with a diluted fertilizer only once new root growth is clearly visible.