Jasmine Harvesting Knowledge: A Detailed Guide to Harvest Time and Methods
The flowering period of jasmine varies depending on the climate conditions of the region. Generally, only when the monthly average temperature is above 20°C and the daily temperature is above 30°C will a vigorous harvest period form. During the flowering season of the year, jasmine forms 3-4 waves of "flower flushes" in a wave-like pattern. Each "flower flush" has about 7 peak production days, called "big water." The periods before or after the "big water" are called "small water." During a flower flush, the daily output difference between big water and small water is 5-10 times, and the interval between "flower flushes" is about one month. For example, the "flower flushes" in Hengxian are divided into:
Spring flower flush: the first flush of the year, generally between April and May, accounting for about 15% of the annual output.
Hundred flowers flush: the second flush of the year, generally from June to July, accounting for about 30% of the annual output.
Dog days flower flush: the third flush of the year, generally in August, accounting for about 30% of the annual output.
Autumn flower flush: the fourth flush of the year, generally from September to November, accounting for about 25% of the annual output.
In terms of quality, because of the higher temperatures, strong sunlight, the coincidence of rain and heat in the same season, and sufficient moisture, the summer and dog days flowers have more buds, larger flower buds, and the best quality, and best reflect the characteristics of the variety. Spring flowers, due to lower temperatures and less accumulation of nutrients, are slightly lower in quality than summer and dog days flowers. The early stage of autumn flowers has the same quality as summer and dog days flowers, while in the later stage the quality is slightly inferior because the weather gradually turns cooler. Jasmine flowers at the beginning of spring and the end of autumn are small and yellow in color, and are relatively difficult to open and release fragrance.
Harvesting fresh flowers is the purpose of jasmine cultivation. Harvest time and harvest standards have a great influence on the yield and quality of jasmine. The harvest standard for jasmine is that the picked flowers can open and release fragrance that same evening; those that can open and release fragrance are called "same-day flowers"; immature flowers picked early before reaching the standard of "same-day flowers" are called "green buds"; flowers that have already opened at the time of picking are called "white flowers." The "green buds" that are picked will not open and release fragrance, so they have no economic value; while the "white flowers" that are picked have mostly already had their aromatic oils naturally volatilized, so their economic value is also not great. Only the ready-to-bloom "same-day flowers" are the harvest target.
The main characteristics of "same-day flowers" are: the flowers are full and white, the flower stem is long, that is, the corolla is long, and the corolla is relatively far from the calyx. The characteristics of "green buds" are: the flowers are not full, the buds are smaller, the color is not white and carries a green-yellow tinge, the corolla is short, and the corolla is relatively close to the calyx. Although "same-day flowers" and "green buds" have fairly obvious differences, if the picking time is too early (such as before sunrise or just after sunrise, from 6-8 in the morning), or if the temperature is relatively low, it is often difficult to distinguish them, so omissions or mistaken picking may occur, causing losses. Therefore, careful distinction must be made when picking. The harvest time should be reasonably arranged, and picking should be done at the proper time. Theoretically, the suitable harvest time is from 2-3 in the afternoon, because in the afternoon the "same-day flowers" have fully developed and matured and have a high aromatic oil content. However, picking in the afternoon is often too late, so jasmine harvesting generally must be moved earlier to after nine in the morning or at noon. After harvesting, jasmine flowers must be protected from squeezing and damage, and must be promptly sent to the scented tea processing factory for care and maintenance.