A Complete Guide to Fertilizing Flowers: Methods and Precautions
Physiological diseases of orchids, also called non-infectious diseases, are disorders caused by unsuitable cultivation environments and care practices rather than pathogenic organisms. Examples include temperatures that are too high or too low, light that is too strong or too weak, imbalanced water and fertilizer, nutrient deficiencies, improper use of chemicals, harmful gases in the air, and toxic substances in the soil. Common orchid...
Fertilizing flowers is fairly complex. The general principles to follow are: apply fertilizer in small amounts but frequently; do not broadcast inorganic chemical fertilizers or let them touch the base of the stems; organic fertilizers must be composted and fully decomposed before use; apply more when plants are growing vigorously in hot, humid summer weather; apply less in winter when low temperatures and weak light slow plant growth; and promptly apply supplementary fertilizer after heavy rain or when leaves are yellow-green and dull due to nutrient deficiency. Fertilizing methods for different situations are as follows: 1. Base fertilizer for flowers - For large-scale field planting of flowers or nutrient seedling beds, decomposed organic fertilizer is mostly used. The base fertilizer application rate is 1500-3000 jin/mu. If cake fertilizer, bone meal, dried livestock manure, etc. are used instead, the rate is 100-200 jin/mu, or a biological fertilizer may also be applied at the same time at 20-40 jin/mu, evenly turned into the soil during land preparation, and planting can be done several days later. Nutrient seedling beds mostly use highly adsorbent media such as peat; before planting seedlings, add an appropriate amount of nutrient elements and let them be fully adsorbed before planting. Trace elements of manganese, iron, zinc, boron, copper, and molybdenum at 0.001-1 ppm may also be added at the same time.
2. Topdressing for potted flowers - Because the medium capacity in pots is limited, potted flowers need a constant supply of various nutrients. For seedlings that have regained green color and produced new leaves, topdressing should begin. The amount of topdressing depends on pot size: apply 40-60 granules of compound fertilizer per pot each time (imported compound fertilizer); for plants that are already growing vigorously, apply 100-120 granules per pot each time, twice a month, plus 5-8 sprays of a formulated liquid fertilizer. After heavy rain, an additional topdressing should also be applied. Topdressing should be applied around the edge of the pot, as far from the stem base as possible, and especially must not let fertilizer granules fall into the center of whorled leaves (such as Dracaena species, Bromeliads, etc.). If flower forcing is needed, spray an additional 0.2% monopotassium phosphate to accelerate flower bud development and make it stronger, generally once every 3-5 days.
Topdressing methods for different types of potted flowers:
① Topdressing for bulbous and succulent flowers - Because bulbs and succulent stems can store nutrients and the root systems are relatively small, the topdressing amount can be half the normal amount. Since they have relatively high requirements for nitrogen, potassium, and calcium, formulated liquid fertilizers often mainly use potassium nitrate and calcium nitrate in combination.
② Topdressing for fibrous-rooted flowers - These flowers need to be planted in loose media, such as Rhododendron hybridum and ornamental bromeliads. Topdressing should be in small amounts and frequent, with the amount being 1/5-1/4 of the normal amount, that is, 15-30 granules of compound fertilizer per pot each time.
③ Topdressing for large-leaved shade-tolerant foliage flowers - These flowers grow rapidly and have well-developed root systems, so they need a lot of fertilizer, such as Rohdea japonica in the Araceae family. In addition to the normal amount applied twice a month with 100-120 granules of compound fertilizer each time, also add 5-8 sprays of formulated liquid fertilizer.
④ Topdressing for bonsai - The characteristics of bonsai fertilization are that the amount should be small and the fertilizer effect should last long. Generally, slow-release organic fertilizers such as bone meal and cake fertilizer are used as the main body, combined with slowly released urea-formaldehyde, rock phosphate, etc., and a small amount of quick-acting fertilizer. If no ready-made bonsai-specific fertilizer is available, commercially sold flower fertilizer can be rolled in olive oil or wrapped with plastic film and treated with liquid to achieve a sustained, long-lasting effect, and the fertilizer can then be shallowly buried under the substrate at the edge of the pot. For large-scale bonsai production, a formulated liquid fertilizer spraying method can be used, spraying once every 3-5 days, with an alternating water spray to wash out salts.
When the potting soil can no longer maintain normal flower growth, symptoms such as yellowing leaves, thin and weak branches, sparse flowers, and small fruits will appear, and then fertilization is needed. However, fertilization must be based on the flower variety, habits, purpose of fertilization, and deficient elements to determine the type, amount, frequency, and method of fertilization.
Home flower growing can be divided into courtyard planting (that is, open-field planting) and potted planting, and fertilization should also differ accordingly. Although courtyard planting differs from field planting, the ground temperature is high and the area is large, making water and fertilizer uptake convenient, so the frequency of fertilizing and watering can be lower, and a slightly stronger fertilizer concentration will not cause fertilizer burn for the time being. Potted planting is different. Due to environmental limitations, on the one hand fertilizer cannot be lacking in order to prevent deficiency symptoms; on the other hand, excessive fertilizer must be prevented because it can cause fertilizer burn to the plants and affect normal growth.
Plant habits also differ between those that like fertilizer and those tolerant of poor soil. For example, fertilizer-loving plants such as citrus, nandina, pomegranate, and Epiphyllum should be fertilized more; while poor-soil-tolerant plants such as rhododendron, black pine, and five-needle pine should be given light fertilizer. Because rhododendron has fine roots and weak fertilizer uptake, too much fertilizer harms it instead, while too little affects flowering.
To fertilize, you must first understand the types of fertilizers and their functions. The basic nutrients for flowers are the three elements nitrogen, phosphorus, and potassium:
1. Nitrogen fertilizer: can promote lush branches and leaves and increase the flowering rate. Common nitrogen fertilizers include human and animal manure, ammonium sulfate, etc.
2. Phosphorus fertilizer: can make flower colors vivid and fruits plump. Common phosphorus fertilizers include rice bran, fish scales, bone meal, chicken manure, superphosphate, etc.
3. Potassium fertilizer: can make the root system grow strong, enhance the resistance of flowers to pests, diseases, cold, and heat, and also increase the fragrance of flowers. Common potassium fertilizers include rice straw ash, plant ash, potassium sulfate, etc.