Valued for their ease of care and stunning blooms, cymbidium orchids (Cymbidium spp.) can produce 30 or more 2- to 5-inch flowers on a single stem. The long-lasting blossoms remain two months or longer on the plant and up to one month as cut flowers. Special bloom fertilizers enhance cymbidium flowers when properly timed. Fertilizing according to cymbidium growth and rest cycles will maximize your cymbidium's blooms.
Cymbidium Growth Cycles
Hardy in U.S. Department of Agriculture plant hardiness zones 10 through 12 cymbidiums are cool-mountain natives with distinct periods of dormancy and active growth. Although it may seem that blooms indicate active times, it's actually the opposite. Cymbidiums flower during their resting period in late fall and winter. While blooming, the plant remains dormant in terms of growth. Bloom fertilizers focus on promoting flowers without encouraging further activity. Once cymbidiums finish blooming, the orchid's energy shifts from flowers back to active new growth.
Cymbidiums prepare for their resting period in late summer. This generally occurs as September begins. Apply bloom-boosting, high-phosphorus, low-nitrogen fertilizers at this time to promote flower spikes. Select a water-soluble fertilizer with the first number low and the middle number high. For example, apply a 10-30-20 or 0-10-10 orchid fertilizer at a rate of 1 tablespoon per 1 gallon of water every one to two weeks, according to the instructions on your product's label. In winter, reduce the fertilizer to once per month. Remember, your orchid is resting even though it's in full bloom. Keep the soil barely moist, and water and fertilize sparingly as spring approaches.
As blooming ends, it's time to prepare for upcoming active growth. From spring to late summer, cymbidiums do their vegetative growing for the year. Use high-nitrogen fertilizer beginning around February to stimulate cymbidium growth. For example, a water-soluble 30-10-10 fertilizer at a rate of 1 tablespoon per 1 gallon of water will suffice. Fertilize every two to three weeks through midsummer or according to your product's instructions. Water heavily during this active period to ensure soil is evenly moist. Though you'll only see foliage and root growth, this nonblooming period prepares your cymbidium for lush blooms.
Rejuvenate your cymbidium every year or two to keep it healthy and receptive to fertilizers throughout the year. Repotting removes dead roots and improves the orchid's access to nutrients. Replacing decomposed planting medium brings new nutrients to the plant. To repot, lift your cymbidium and gently remove remaining soil. Remove any dead or unhealthy roots. Cymbidiums prefer tight quarters, so repot your orchid in a container that allows only 2 to 3 inches around the plant. Excellent drainage is essential; cymbidiums won't tolerate standing water. A commercial orchid mix or a mix of two parts orchid bark, two parts peat moss and one part sand provide a healthy mix to promote and enhance future cymbidium blooms.