Precautions for Soilless Cultivation of Flowers and Fertilizer Application Methods and Techniques
I. Fertilizer Application Methods
Basic principles: apply at the right time and in the right place, in small amounts and multiple times, frequently and lightly. This is especially true for powdered chemical fertilizers; the dilution ratio with water should be moderate to avoid fertilizer burn. Fertilizer should be placed as far as possible at the edge of the pot or away from the roots, avoiding direct contact with the plant's roots and not damaging the roots. Outdoor plants have high nutrient demands, strong photosynthesis, and need more fertilizer, while plants in shady areas need less fertilizer. Plants that grow quickly and have strong vigor need more fertilizer, while those with weak vigor need less. Prepare precisely according to the specified concentration.
II. Fertilization methods can generally be divided into two types: root fertilization and foliar spraying.
1. Root fertilization can be divided into broadcast application, hole application, band application, and ring application. Broadcast application: spread the fertilizer evenly on the soil surface of the planting area. It is convenient to apply, but the fertilizer is easily lost and the utilization rate is low. Band application: in a strip-planted crop garden, dig trenches between crop rows, apply the fertilizer, and then cover with soil. Hole application: dig holes near the plant, apply the fertilizer, and then cover with soil. This method is suitable for plants that need more fertilizer or need it in a concentrated way. Ring application: suitable for perennial fruit trees. Dig a trench about 30 cm deep along the drip line of the fruit tree, apply the fertilizer, and then cover with soil.
2. Foliar fertilization: dissolve the fertilizer in water to form a fertilizer solution and then spray it on the plant leaves. The fertilizer used should be easily soluble in water, contain no toxic substances, and not burn the leaves.
Advantages of foliar fertilization: rapid absorption and timely nutrient supplementation; it can increase leaf photosynthetic intensity, improve leaf respiratory efficiency and enzyme activity; it avoids fixation of nutrients, has a high utilization rate, and saves fertilizer; it is not limited by the substrate (soil) environment or substrate (soil) conditions; and it promptly corrects symptoms of element deficiency.
Requirements for foliar fertilizer: the ratio among elements should be reasonable to avoid antagonism between elements; the pH value should be controlled within a reasonable range (5.5-6.5); buffering capacity should be strong, and after application it must be ensured that the substrate pH value will not change greatly due to physiological reactions; the EC value should be relatively low to ensure high safety in use; the raw materials should be of high purity and contain no harmful salt ions (Na+, Cl-, SO42-, etc.); trace elements should be in chelated form to improve the absorption effect of trace elements; nitrogen sources should be diverse (ammonium nitrogen, nitrate nitrogen, urea nitrogen), and the ratio should be reasonable to ensure the nutritional needs of plants at different stages.
III. Improving Fertilizer Utilization Rate
Fertilization can promote crop growth, but fertilization should not be done blindly. It must be targeted according to different soil (medium) conditions, different crops, and different growth stages. Otherwise, it will not only fail to promote growth, but may also cause physiological disorders in plants and affect normal growth. Therefore, corresponding fertilization measures should be taken according to actual conditions to improve fertilizer utilization rate.
1. Combine controlled-release fertilizer with water-soluble quick-acting fertilizer, balancing slow and fast release, to ensure that plants have sufficient nutrient supply throughout every growth process.
2. Strictly control the acidity and alkalinity of the cultivation soil (medium). According to scientific research, most nutrient elements are easily absorbed and utilized by plants at a pH value between 5.5 and 6.5, with high availability. Therefore, the acidity and alkalinity of the soil (medium) should be monitored and controlled regularly so that the availability of nutrient elements is at its highest.
3. Select the best fertilizer formula according to the different growth stages of the plant.
The seedling stage is the vegetative growth stage of the plant and a critical period for plant growth. To enable the plant to grow healthily, it is necessary not only to increase the nitrogen content in the fertilizer, but also to consider a balanced ratio of nitrogen, phosphorus, and potassium and to add an appropriate amount of trace elements to promote the growth of roots, stems, and leaves. For example, use Osmocote as a base fertilizer, and for topdressing use Peter's Professional 1 (20-20-20) and Peter's Professional 10 (30-10-10) for foliar spraying.
Phosphorus can promote root development and flowering in plants. To promote flower bud differentiation, increase carbohydrates to raise the carbon-to-nitrogen ratio. It is recommended to use Peter's Professional 2 (10-30-20) or Peter's Professional 15 (9-45-15) for foliar spraying.
To make flower buds large and numerous, spray with Peter's Professional 2 (10-30-20) during the flowering stage.
The fruiting stage is the final stage of the plant growth cycle. Water-soluble quick-acting fertilizer should be sprayed. The fertilizer should contain relatively high phosphorus and potassium, and at the same time supplement calcium and magnesium to increase the sugar content of the fruit, enhance the disease resistance of the fruit, make the fruit suitable for long-distance transport, and extend storage time. Use Peter's Professional 23 (15-5-15-5Ca-2Mg) for spraying.
4. Apply special fertilizers according to different physiological characteristics, achieving "supplementing whatever is needed." Special fertilizers are produced by fertilizer manufacturers according to formulas designed for the physiological characteristics and growth requirements of different plants, such as Peter's Professional 3 (special fertilizer for poinsettia, 15-20-25), Peter's Professional 20 (special fertilizer for azalea, 21-7-7), etc.
5. Different water quality requires different fertilizers. For example, in soft water areas, attention should be paid to supplementing calcium and magnesium.
6. Fertilization time is also very important. On sunny days with high temperatures, fertilization should be chosen before 10 a.m. or after 4 p.m., avoiding fertilization under strong direct sunlight. Avoid fertilizing on rainy days, especially foliar fertilizer, to prevent fertilizer loss.
7. Every plant has an optimal fertilization plan. Different plants require different types of fertilizer and different formulas.