How to Determine Water and Fertilizer Deficiencies in Orchids
As a traditional famous flower in China, the care of orchids requires precise mastery of water and fertilizer management. This article will analyze diagnostic techniques and remedial measures through four core points to help growers establish a scientific care system.
Diagnostic Criteria for Water and Fertilizer Deficiencies in Orchids
Typical Symptoms of Water Deficiency Identification
When the moisture content of the potting soil is below 15%, the first sign is the shriveling of pseudobulbs, followed by longitudinal wrinkling of the leaves. In severe water deficiency, the tips of old leaves develop burn spots, and the surface of new leaves loses their waxy luster. Special attention should be paid to false water deficiency caused by overly coarse growing medium particles; it is recommended to use the bamboo skewer method to confirm moisture.
Classification and Analysis of Fertilizer Deficiency Characteristics
The three essential elements—nitrogen, phosphorus, and potassium—manifest differently when deficient: nitrogen deficiency results in thin and elongated new leaves; phosphorus deficiency causes leaf edges to curl inward; potassium deficiency leads to leaf tip browning. A magnesium deficiency forms V-shaped yellow spots, while an iron deficiency causes new leaves to become yellow and white. It is recommended to conduct leaf SPAD value tests monthly to accurately assess nutritional status.
Scientific Water and Fertilizer Supplement Plan for Orchids
Gradual Watering Techniques
After detecting dehydration, the immersion method should be used to revitalize the plant, ensuring that the water temperature matches the ambient temperature. Daily care should follow the principle of 'wet when dry, and moist when wet,' maintaining a substrate moisture of 30%-40% in spring and autumn, and increasing to 50% in summer. It is suggested to pair this with an intelligent humidity monitor to establish a watering cycle database.
Targeted Fertilization Operation Standards
When nitrogen is deficient, urea should be diluted to 800 times the liquid concentration, and the foliar spray concentration should be controlled at 0.2%. Phosphorus fertilizer supplementation is recommended with monopotassium phosphate at 2000 times the liquid concentration for root irrigation, combined with EM agents to enhance absorption. Magnesium deficiency can be addressed with magnesium sulfate at 500 times the liquid concentration, alternating with chelated iron fertilizer for better results. Note that fertilization should be stopped during high-temperature seasons to avoid fertilizer damage.
By establishing a 'observe-diagnose-treat' integrated care system, combined with regular potting medium testing and growth log recording, the success rate of orchid care can be significantly improved. It is recommended to conduct potting medium EC value tests every quarter, dynamically adjusting the water and fertilizer plan to keep orchids in the best growing condition.