Diagnosis and Correction of Nutrient Deficiencies in Orchids

When an orchid lacks a certain nutrient, it will show signs on the plant. Based on these signs, the nutrient deficiency can be diagnosed and corresponding measures taken to correct it.

① Nitrogen deficiency. It manifests as new leaves being shorter and narrower than old leaves, thin in texture, pale yellow in color, and lacking luster. You can water the roots with a 500-fold dilution of potassium sulfate compound fertilizer or potassium nitrate compound fertilizer, and spray a 0.2% urea solution on the leaf surfaces and undersides in the evening. Spray once every three to five days, for 3 consecutive sprays, and it can be corrected.

② Phosphorus deficiency. It manifests as slow growth of leaf buds, roots failing to emerge for a long time, and leaf margins slightly curling backward. You can water the roots with a 2% superphosphate extract, or a 3%-5% bone meal solution, or an 800-fold dilution of monopotassium phosphate, once every 10 days, for 2 consecutive waterings; and spray a 600-fold dilution of monopotassium phosphate, or a 1000-fold dilution of Huabao No. 3, on the leaf surfaces and undersides in the evening, once every three to five days, for 3 consecutive sprays, and it can be corrected.

③ Magnesium deficiency. It manifests as old leaves turning yellow; the leaf tips and margins of middle-aged leaves turning yellow and curling toward the leaf surface (commonly known as "gong-rim"). You can spray a 0.5% magnesium sulfate solution on the leaves in the evening, once every three to five days, for three to five consecutive sprays, and it can be corrected.

④ Potassium deficiency. It manifests as leaf margins and leaf tips turning yellow (old leaves first, then new leaves), then turning brown; the main and lateral veins of the leaves becoming thinner; the leaf texture becoming soft and prone to bending and drooping; if exposed to strong light and low temperatures, new leaves show slight dehydration. You can first water the roots and spray the leaves with a 0.5% potassium sulfate solution, or spread wood ash.

⑤ Manganese deficiency. It manifests as sunburn-like spots appearing even with proper shading, with spots within spots, flower buds not developing; leaves shriveling, losing green color, and lacking luster. Manganese deficiency symptoms are more likely to appear in neutral, calcareous, and sandy soils. Spraying a 0.3% manganese sulfate solution on the leaves 3 times can correct it.

⑥ Calcium deficiency. It manifests as leaf tips forming a hook shape (except where this is a varietal characteristic). It is commonly seen in plants given acidic fertilizers. You can water the roots once with a 1.0% lime solution, or apply a 3% solution of livestock calcium powder once, and it can be corrected.

⑦ Iron deficiency. It manifests as the mesophyll of young leaves turning yellow to white, with the central veins, leaf margins, and leaf tips showing scorched brown necrotic spots. You can spray a 0.5% ferrous sulfate solution on the leaves, once every 3 days, for two to three consecutive sprays, and it can be corrected.

⑧ Zinc deficiency. It manifests as rust-like spots appearing in the middle section of the bottom leaves, gradually spreading toward both ends of the leaf; the petiole ring of new growth being noticeably lower than the petiole ring of old leaves. You can spray a 0.1% zinc sulfate solution on the leaves, once every three to five days, for 3 consecutive sprays, and it can be corrected.

⑨ Copper deficiency. It manifests as leaf tips losing green color, gradually turning grayish-white and spreading to the entire leaf, with growth stagnating. You can spray a 0.2% copper sulfate solution, once every 7 days, for 2 consecutive sprays, and it can be corrected.

⑩ Boron deficiency. It manifests as the base of young leaves being damaged, the petiole ring being extremely brittle and easily broken, the number of flowers per scape noticeably reduced, flower buds opening slowly and looking listless when open, and the lasting period of flowers after blooming being noticeably shortened. You can spray a 0.3% borax or boric acid solution, once a week, for 3 consecutive sprays, and it can be corrected.

⑩ Molybdenum deficiency. It manifests as new growth being noticeably dwarfed even without applying chlormequat; old leaves losing green color, leading to yellowing, wilting, and necrosis. You can spray a 0.1% ammonium molybdate solution, once every 3 days, for 3 consecutive sprays, and it can be corrected.

If fertilizer is applied according to what the orchid plant lacks, keeping the nutrient elements of the plant relatively balanced, then the functions of all the plant's organs can be fully brought into play and work in coordination, which has a very good effect on increasing yield and quality.