6) Actions related to ‘me’amer’ (winnowing) [Excerpted from The 39 Melachos by Rabbi D. Ribiat, Vol. II pp. 305-313]
The definition of Me’amer. After reaping (‘kotzair’), the cut stalks of produce were gathered, to be brought later to the threshing grounds. According to some commentaries, the stalks of produce were gathered and tied into bundles. This process was the melacha of ‘me’amer’…. Me’amer is the collecting or combining of scattered fruits, produce or any other substance (possibly - even non-food) that grows from the ground… Even collecting just two fruits is the melacha. Consolidating what has already been gathered (e.g. compacting a mound of dates into one solid mass) is also me’amer.
The exemptions of me’amer. According to many poskim, there are as many as four separate conditions under which me’amer is exempted. As a result, the restriction of me’amer is quite limited for most practical purposes, and in fact, gathering most objects is usually permitted on Shabbos. The following are the four conditions to me’amer:
1) The items must be earth-grown* (Heb. ‘gidulei karkah’)
2) It must be gathered in its place of growth
Heb. ‘bim’kom gidulo’)
3) Regathering is not me’amer (Heb. ‘Ein me’amer achar me’amer’)
4) The gathered objects must be in their original state.
*According to some poskim, natural mineral deposits (including rock and stone) that develop in the earth are regarded as ‘gidulei karkah’ (earth-grown) with respect to me’amer. According to this view, gathering chips or slabs of lime stone or marble in their mining areas is me-amer mid-oraisa (i.e. a Torah violation – aside from other rabbinic transgressions, such as muktzah.) Similarly, natural salt (mined from the earth) is considered gidulei karkah, because it is, after all, a natural mineral deposit. Collecting chunks of such salt from shallow deposits would also be me’amer mid-oraisa according to this view… However, in the time of the Talmud, salt was obtained primarily from the salty seawater (whereas, today, most salt is mined.) Salt would be extracted from the seawater by a method known as solar evaporation. The Talmud states that one may not collect these sea-salt deposits on Shabbos, because this gathering operation resembled me’amer. Although the sea-salt is certainly not considered true ‘gidulei karkah’ according to ALL views, nevertheless, collecting sea-salt is similar to me’amer, in that the salt appears as if it “grew” in that area. Gathering the salt, therefore, resembles an act of me’amer (and is forbidden.)
2) Making a bouquet of flowers.