When did the north begin to grow wheat?

In the past ten years, the sowing time of winter wheat in the north was basically the autumnal equinox solar term, and the sowing was basically completed in the first frost solar term.

Judging from the agricultural proverbs handed down from ancient times, the best time to sow winter wheat in northern China is the Bailu solar term. "Millennium is early, cold dew is late, and wheat is planted in the autumn equinox." In other words, when the Millennium solar term comes, there will be winter wheat sowing, just a little early; It's a little late to broadcast the cold dew solar terms again; The best solar term for sowing winter wheat is the autumn equinox.

With global warming, the sowing date of winter wheat has been delayed by about fifteen days, and the agricultural proverb for sowing winter wheat has been changed to "the autumn equinox is early, the first frost is late, and the cold dew wheat is just in time".