Cymbidium orchids, known for their abundant, long-lasting blooms, are a rewarding addition to any plant collection. These popular orchids, often called boat orchids, produce impressive flower spikes. Achieving vibrant growth and prolific flowering in Cymbidiums relies on proper nutrition. Fertilization is fundamental to their care, ensuring they receive elements to support their growth cycles and stunning floral displays.
Understanding Cymbidium Nutritional Needs
Cymbidium orchids require a balanced array of nutrients. Macronutrients, needed in larger quantities, include nitrogen (N), phosphorus (P), and potassium (K), represented as the N-P-K ratio on fertilizer labels. Nitrogen supports lush foliage and vegetative growth. Phosphorus is essential for healthy root development and promotes abundant flower production. Potassium enhances the plant’s resistance to environmental stressors and diseases.
Cymbidiums also depend on secondary macronutrients like calcium (Ca), magnesium (Mg), and sulfur (S), and various micronutrients. Calcium aids cell wall construction and new growth. Magnesium, a component of chlorophyll, is important for photosynthesis.
Iron, a micronutrient, is involved in chlorophyll production and enzyme function. Other micronutrients such as boron, zinc, copper, manganese, and molybdenum are necessary in trace amounts for metabolic processes. Cymbidiums are considered relatively heavy feeders, especially during active growth.
Choosing the Right Cymbidium Fertilizer
Selecting fertilizer involves understanding N-P-K ratios and micronutrient presence. Fertilizers come in liquid, slow-release pellets, and specialized orchid blends. Balanced fertilizers, like 20-20-20, suit general maintenance when the orchid is not blooming.
During blooming, Cymbidiums benefit from bloom booster fertilizers with higher phosphorus, such as 10-30-20. Some growers use slow-release granular fertilizers mixed into the potting medium for extended nutrient release. Choose fertilizers with a comprehensive range of micronutrients for complete plant nutrition. Organic fertilizers like fish emulsion or seaweed extract offer a gentler nutrient release.
When and How to Fertilize Cymbidiums
The timing and method of fertilization align with their growth cycle. During active growth (spring through late summer), Cymbidiums require frequent feeding. The “weakly, weekly” approach applies diluted fertilizer (one-quarter to one-half strength) with each watering, or every two weeks. Higher nitrogen (e.g., 30-10-10) can be used from March to May for vegetative growth, then a balanced formula (e.g., 20-10-20) from June to September.
As fall approaches and flower spikes form, shift to a lower nitrogen, higher phosphorus and potassium formula (e.g., 3-12-6 or 10-30-20) to support blooming. During winter or dormancy, reduce feeding to once a month or every other watering. Before fertilizing, water the orchid thoroughly to prevent root burn. Regularly flush the potting medium with plain water (monthly) to prevent fertilizer salt buildup, which damages roots.
Common Fertilization Issues and Solutions
Incorrect fertilization leads to problems. Over-fertilization is common, causing burned root tips, yellowing or browning leaf margins, and stunted growth. A white crust on the potting medium or pot indicates salt buildup. If these signs appear, leach the potting mix by flushing with plain water to remove salts. Reducing the fertilizer strength and frequency of application is also necessary.
Nutrient deficiencies show specific symptoms. Yellowing leaves, especially older ones, indicate nitrogen deficiency. Lack of growth or poor blooming suggests insufficient phosphorus.
Yellowing leaves between veins points to iron deficiency. Stunted growth or discolored leaves can also signal nutrient imbalance. Address deficiencies by adjusting fertilizer type to provide missing nutrients.