When to Fertilize Grapevines
Summary: This article provides some small experiences in caring for fruit trees, specifically when to fertilize grapevines. Detailed introduction is provided below:
In the process of caring for fruit trees, fertilization is indispensable. Some fruit farmers ask when to fertilize grapevines. Generally, there are five important points in fertilizing grapes, as follows:
Germination Fertilizer: It is usually applied before the grapevines start to bud. This time, nitrogen fertilizer (a large-element water-soluble fertilizer is recommended) is the main component, aiming to promote uniform germination, thick leaves, and large inflorescences. If the tree is too vigorous and not too dry in spring, this fertilization can be omitted to avoid causing the new shoots to grow excessively.
Swelling Fertilizer: It is applied after the grapes have set fruit, when the fruit is the size of mung beans to soybeans. This fertilizer mainly contains nitrogen, with phosphorus and potassium fertilizers also applied. High-nitrogen compound fertilizers can be used, or common three-element compound fertilizers, with urea and other nitrogen fertilizers added as appropriate. The amount of this fertilizer should be large, accounting for about 50% of the annual chemical fertilizer application.
Maturity Fertilizer: This is done in two steps. 20-30 days before maturity, a high-potassium water-soluble fertilizer is applied. Another application is made when the grape berries start to soften but have not yet colored.
This fertilization is very important. Many fruit farmers do not apply maturity fertilizer after applying the swelling fertilizer, which can cause the fruit to change color (commonly known as the "water jar disease") or, due to lack of fertilizer, the grapes have poor resistance and are prone to diseases, resulting in high yield but not high income. Or poor coloring, low sugar content, and unable to sell at a good price, etc. Functional fertilizers can be directly applied, such as large-element water-soluble fertilizers for coloring (recommended high-phosphorus high-potassium types like phosphorus-potassium source library, which also contains trace elements boron and zinc).
Post-Harvest Fertilizer: This refers to applying a fertilizer immediately after grape harvesting, usually a large-element water-soluble fertilizer (high-nitrogen type) of 15 kilograms. The function of this fertilizer is not only to restore the tree's vigor but also to promote flower bud differentiation, laying the foundation for next year's high yield.
Overwintering Fertilizer: The traditional method is to apply during the grapevine's dormant period. In recent years, it is recommended to apply in August or September, after the grapes have been harvested and while the vines are still green and growing. This is the second peak of grape root growth, which can promote the production of a large number of fibrous roots to strengthen the tree and is more conducive to overwintering. This fertilizer mainly consists of organic fertilizers (if using farmyard manure, make sure it is fully decomposed!) and also includes calcium fertilizers, or a small amount of three-element fertilizers may be added.
Note: After each fertilization, it is necessary to water thoroughly, but not excessively. Too much water can cause fertilizer loss. After applying the swelling fertilizer, two waterings should be done consecutively, usually with a 5-7 day interval. Moreover, before grapes overwinter, a thorough watering is necessary, followed by tilling the soil when it is loose, which is extremely beneficial for frost prevention.
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