Deuteronomy 16:13

Thou shalt observe the feast of tabernacles seven days
Which began on the fifteenth day of Tisri, or September; see ( Leviticus 23:34 ) , &c.

after that thou hast gathered in thy corn and thy wine;
and therefore sometimes called the feast of ingathering, ( Exodus 23:16 ) , barley harvest began at the passover, and wheat harvest at Pentecost; and before the feast of tabernacles began, the vintage and the gathering of the olives were over, as well as all other summer fruits were got in.