I doubt very much whether a good harvest is possible in August in Germany, but it might well be in Israel...
as to the phrase "tending vines" - this just means "taking care of vines", and, in my opinion has nothing to do with the harvesting of them.

On the other hand, the original language is probably Hebrew or Yiddish, and who knows how good the translations into English and German actually are....

Obviously it is not correct. But of course the translator may have been correcting a mistake in the original. If the picture depicted grapes being harvested, then clearly he was right to say so. As a translator, I find myself doing this all the time (the client is informed, of course).

Das ist die Zeit der Arbeit im Weinberg, Pflege der Reben

Fully support Dr. med. Leistenschneider

Wie ich aus persönlicher Erfahrung weiß, findet die Weinernte in Israel definitiv Ende September, Anfang Oktober statt. Von Juni-August werden die Plänzchen gehegt und gepflegt...