When will the southern sour jujube mature

Found a problem, when I was a child, the sour jujube was not ripe, it was so sour that I lost my teeth, and the sour jujube I ate when I was a child was green, but the color of the mature sour jujube was not like this. Let's see when the southern sour jujube will mature.

The fruit is ripe in October, when the peel changes from green to yellow, it is knocked off or naturally picked up, stacked and retted, scrubbed to remove the pulp, dried and stored in sand.

Sour jujube, also known as four-eye fruit, Hualang fruit, snot fruit, for the lacquer tree plant sour jujube. Distributed in Zhejiang, Fujian, Hubei, Hunan, Guangdong, Guangxi, Yunnan, Guizhou and other places, the core of southern sour jujube is large and very hard, because it has five eyes at the top, it has symbolized the meaning of "Wufu Linmen" since ancient times. Drupe oval or Obovate, yellow when mature, mesocarp fleshy pulpy, flowering April, fruiting August-October.