Q. Several years ago I purchased a cymbidium orchid plant in bloom. I’ve given it good care, but it has never flowered again. It’s next to a window where it receives good light, it gets regular fertilization and watering, and it’s on a humidity tray. What more can I do?
A. Cymbidium orchids are considered one of the easier orchid plants for the beginner to grow. However, your experience is not at all uncommon. Because I have received a number of inquiries regarding cymbidiums, I would like to cover their cultural requirements in general before getting to the likely cause of your problem.
In mild winter areas, such as ours, cymbidiums may be grown outdoors. They will withstand winter temperatures that drop to 30 degrees and summer temperatures that approach 100 degrees without serious damage. When temperatures approach the lower limit, a shelter covered with polyethylene is necessary. At the upper limit, shading and misting to reduce leaf temperatures become important.
As you mentioned, lighting is important. When grown outdoors, only light shading is necessary. Shade cloth of 55 percent density is recommended, but there are other possibilities. I have had success growing potted cymbidiums beneath a peach tree in my garden, and I’ve seen others grow them beside east-facing house walls. Leaf color on a plant receiving proper light is yellowish-green. Dark green leaves indicate insufficient light, and bleached or scorched leaves indicate too much light.
During the growing season (spring to fall), plants should be watered every few days to keep the coarse potting mix moist, and a 30-10-10 fertilizer can be added to the irrigation water. Weekly irrigation is sufficient during late fall and winter, and a fertilizer with a 10-10-10 analysis should replace the fertilizer used during the growing season.
There are two common conditions that may cause cymbidiums to fail to bloom. The first is insufficient light, which I’ve already covered. The second is an insufficient day-to-night temperature differential.
During the fall, cymbidiums require at least a 20 degree difference between day and night temperatures to trigger flower spike initiation. For most cymbidiums, a day temperature under 80 degrees and a night temperature of 40-60 degrees during the fall would be ideal. Plants grown indoors frequently fail to receive this necessary differential and consequently fail to flower even when all other conditions are perfect.
I suspect that this is the cause of your plant’s problem. It’s probably too late this year to remedy the problem, but I suggest that you find a cool place for your plant to spend its nights next fall and winter. Hopefully, you’ll be rewarded with flower spikes the following year.
Ottillia “Toots” Bier has been a UC Cooperative Extension master gardener since 1980. Send comments and questions to features@pressenterprise.com.
