Generally speaking, oysters take about 3 years to grow up. Moreover, spring and summer are the breeding and growing periods of oysters. At this time, oysters are thinner and secrete an unpleasant body fluid. Therefore, oysters in spring and summer not only have low nutritional value, but also have poor taste.

Winter is the ripe harvest season for oysters, and Tomb-Sweeping Day can harvest them all the time next year. Oysters, meat and fat juice are fresh at this time, so winter is the best time to eat oysters. But now the oyster market has been in short supply. If the harvest is carried out according to the normal growth period of three years, it is far from meeting the market demand.