Enhanced Cymbidium ‘PCMV’ Hybrid Orchid Yield through Calcium Nutrition: Deep Insight into Ca Dynamics among Different Plant Parts at its Various Growth Stages

Calcium (Ca) is an essential nutrient for all crops, including orchids. However, scientific studies specifically focusing on Ca nutrition in Cymbidium orchids are rare. This study aims to address this gap by exploring the crucial role of Ca in the cultivation of Cymbidium orchids. Cymbidium hybrid ‘Pine Clash Moon Venus’ (PCMV) orchids were cultivated with six Ca treatments (with 0 to 100 mg Ca L⁻¹ fertigation solution). The potting media under Ca₁₀₀ treatment maintained a near-neutral pH, with significantly higher dehydrogenase activity over Ca₀ treatment. The Ca₁₀₀ treatment produced significantly higher vegetative yield and 100% higher number of flower spikes compared to Ca₀ treatment. The flower spikes from Ca₁₀₀ treatment were ~ 72% longer in length, and bore ~ 72% higher number of florets per spike compared to those from Ca₀ treatment. Ca application significantly enhanced Ca concentrations in different plant parts. Flowering-induced Ca removal significantly reduced Ca content from orchid back bulbs, but not from other plant parts. Partial regression analysis revealed that one-unit Ca uptake by flowers resulted in ~ 0.279 unit decrease in Ca content in the back bulbs. The study underscores the positive impact of Ca application on Cymbidium yield, also provides novel insights into Ca dynamics across various plant parts of the orchid, and recommends weekly application of 100 mg L⁻¹ Ca for improving Cymbidium cultivation practices.