Cymbidium orchids are much more likely to produce abundant numbers of stems lined with flowers if plant clumps are exposed to cool, frost-free temperatures in fall and winter. Always appreciating good air circulation around their yellow-green, straplike leaves, cymbidiums also need bright but indirect light. In the warmth of the growing season, these orchids grow well with moderate watering and occasional fertilizing, but with the onset of winter temperatures, watering and fertilizing diminishes. While hardy outdoors in USDA zones 8 and warmer, it's best to never expose the plants to frosts in order to keep foliage looking good and prevent harm to flower buds.
Relocate your cymbidium orchids to a location that is protected from fall and winter frosts, or nighttime temperatures that drop below 35 degrees F. Although foliage and developing flower buds may survive temperatures as low as 27 to 29 degrees F without harm, it's best to keep them in a setting with temperatures between 35 and 45 degrees F at night and only 60 to 72 degrees F during the day in winter.
Situate the orchids so that they receive more direct sunlight in winter. Don't worry, the sun rays in winter are weaker and this gentle sunlight is needed to sustain growth in the cooler, drier winter months.
Reduce watering the cymbidium orchid to once every seven to 10 days in winter. Modify your watering schedule from that of summer so that the plants are kept much drier than in the growing season. Don't abandon watering, though, as you want to sustain the plant with barely moist soil with waterings.
Fertilize once per month at most during the winter. According to the American Orchid Society, mix the fertilize at normal, full strength as you do in the summer growing season. Unlike summer, the winter fertilizing is much less frequent. Use a high-phosphorus fertilizer, such as 10-30-20.
Maintain temperatures between 55 and 75 degrees F once flower buds are visible on the plants. Depending on the species, cymbidiums may begin producing flower spikes as early as mid-fall depending on how much cool weather they endured beginning in late summer onwards.