Kommentar zu Sheviit 9:7

עניים נכנסים לפרדסאות – in the rest of the years of the Seven Year [cycle], [the poor] gather gleanings and the forgotten sheaves and the corner of the field, and similarly, they enter to the gardens in the aftermath of the Seventh Year

Similarly, if one rents a house to someone “until the rains,” he means until the second rainfall.
Or if one had vowed not to derive any benefit from his friend “until the rains” [he is prohibited] until the second rainfall.
Until when may the poor enter the orchards? Until the second rainfall.
And when may one begin to enjoy or burn the straw and stubble of sabbatical produce? After the second rainfall.
This mishnah deals with various other halakhot that have to do with “the second rainfall.”
Sections one and two: The meaning of “until the rains” is established by our mishnah as being until the second rainfall.
Section three: In non-sabbatical years the poor can enter the orchards to collect various types of produce that are given to the poor (forgotten foods, corners of the fields, dropped food all of this was discussed at length in Peah). They can enter the orchard after the second rains have fallen.
Section four: Straw and stubble that are animal food cannot be burned during the sabbatical year. However, once the second rainfall has come and ruined the straw and stubble which is still found in the field, one can burn that which remains in his home and even derive benefit from such burning.

until the second rainfall occurs, because the fruits/produce of the Seventh Year that remained from it are permitted.

בתבן ובקש של שביעית – for mere straw and stubble are fit for consumption by animals and they have the sanctity of the Seventh Year, and it is prohibited to burn it and to derive the benefit of [destruction], because we expound (see Mishnah Sheviit, Chapter 8, Mishnah 1 – and Leviticus 25:6): “But you may eat whatever he land during its sabbath will produce,” and not for loss. But when it is abolished, what was in the field from the food for live beasts, it released the Sanctity of the Seventh Year from what is in the house.