חַ֧ג הַסֻּכֹּ֛ת תַּעֲשֶׂ֥ה לְךָ֖ שִׁבְעַ֣ת יָמִ֑ים בְּאָ֨סְפְּךָ֔ מִֽגָּרְנְךָ֖ וּמִיִּקְבֶֽךָ׃
Thou shalt keep the feast of tabernacles seven days, after that thou hast gathered in from thy threshing-floor and from thy winepress.
Rashi on Deuteronomy
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).
Sforno on Deuteronomy
ומיקבך ,when you gather in the harvest into your houses and your barns from the grain presses and wine presses.
Rashbam on Deuteronomy
באספך מגרנך ומיקבך, I have already explained the connection between the word באספך and חג האסיף etc., in my commentary on Leviticus 23,43.