Commentaire sur Le Deutéronome 16:13

באספך [THOU SHALT KEEP THE FESTIVAL OF TABERNACLES …] AFTER THAT THOU HAST GATHERED IN THE PRODUCE — i.e. at the usual harvest time, when thou bringest into the house the summer fruits. Another explanation is: באספך מגרנך ומיקבך teaches that one should cover the Succah only with the פסולת (lit., the chips, — that which falls off) of the barn and the wine-press [i.e. with vegetable matter] (Rosh Hashanah 13a; Sukkah 12a).

ומיקבך ,when you gather in the harvest into your houses and your barns from the grain presses and wine presses.

באספך מגרנך ומיקבך, I have already explained the connection between the word באספך and חג האסיף etc., in my commentary on Leviticus 23,43.