The fertilization of Rhododendron should be determined according to the flower age. It is not suitable to apply fertilizer at the seedling stage. The growth of 2-3 years can increase the application of P and K fertilizer, and the old plants can apply more N fertilizer. In addition, we should control the time of fertilization, generally in spring and autumn. Before fertilization, the fertilizer should be fully diluted and controlled for a period of time. After fertilization, it should be more permeable, which is conducive to its absorption.
1. Growth period: Rhododendron has two growth periods. One is in spring. At this time, the rotten cake fertilizer is applied 3-4 times a month. It must be fully diluted before fertilization. After autumn, it enters the second growth period. At this time, it is in flower bud differentiation and cut-off. It is necessary to apply a certain amount of P and K fertilizer, and water the next day after fertilization to avoid burning the roots.
2. Prophase of flower: provide sufficient nutrients for Rhododendron in the prophase of flower. At this time, the fertilizer is mainly phosphate fertilizer, which can be mixed with a certain amount of potassium fertilizer. Less or no application of nitrogen fertilizer, it will hinder flowering.
3. Late flowering stage: nitrogen fertilizer should be added immediately after flowering and withering. At this time, the plant lacks nutrients. Nitrogen fertilizer should be applied once every 10 days, which is more beneficial to the growth of branches and leaves. From August to October, to increase a certain amount of phosphate fertilizer, once every half a month, is very helpful for the second year of flowering.
