In an attempt to define terms and the length of time that a neder must be kept, the Mishna on our daf distinguishes between “until the summer” which means until the summer begins, and “until the summer passes” which means until the summer is over.
The Hebrew word kayitz, קיַץִ, has two distinct but related meanings: “Summer” and also “figs” (See II Shmu’el 16:1-2, where the term is used to mean specifically the period of the fig harvest.) The relationship between the two meanings lies in the fact that figs are harvested in late summer(see Yeshayahu 28:4). Kayitz, when used as the name of a type of fig or as a name for the fig harvest is also connected to the root kuf, yod, tzadi, meaning cutting or picking.
In truth, our Mishna is referring to the fig harvest. Thus we find that the kayitz begins when the fruit is collected in baskets and it ends when the maktzuot are folded up. What exactly the folding of the maktzuot means is the subject of some discussion among the rishonim.
Most rishonim (including Rashi and the Ritva) suggest it means that the knives used for harvesting are stored away. Some suggest that they were foldable knives, which is why they are referred to in that way. The Aruk explains that the figs were strung together when they were dried. The strings of figs are called ketziot, and folding the maktzuot refers to the completion of this process.
The Rambam, in both his Commentary to the Mishna and in his Mishneh Torah, explains that maktzut are the mats on which the figs were dried. Folding up the mats was an indication that the season was over and that they were being stored for next year.