משנה על שקלים 34:3

If one gathered moist herbs, he may eat them until the sweet [herbs in the field] have dried up. And if he gathered dry [herbs], [he may eat them] until the second rainfall. Leaves of reeds and of leaves of the vine [may be eaten] until they fall from the stems. But if he gathered them dry, they may be eaten until the second rainfall. Rabbi Akiba says: in all these cases, [they may be eaten] until the second rainfall.