The seventh day of Sukkos is known as Hoshana Rabbah, the day of many Hoshanos (or Hosanna’s). We will attempt to shed some light on the practices of the day.
The origins of Hoshana Rabbah are in the Mishnah (Sukkah 4:5) which informs us that the custom was to circle the Mizbeach one time on each day of Sukkos and seven times on the seventh day. So too we circle the Bimah one Hoshana each day of Sukkos and seven Hoshanos on the Seventh day.
Hosha Na is literally a plea for salvation. In the Beis Hamikdash while circling the Mizbeach they would exclaim either ‘Ana Hashem Hoshea Na’ from the Hallel prayer, or ‘Ani V’Ho Hoshia Na’ which Rashi explains is the Gematria of Ana Hashem. [Rashi, in an unusual deviation from his classic pshat style offers an alternative Kabalistic explanation based on the verses describing the Clouds of Glory surrounding the Jewish People in the desert.
The Rishonim explain that the reason that this is specifically done on the seventh day of Sukkos is as follows: Sukkos is the Day of Judgment for water. This means rain and, in a broader sense, all livelihood. We therefore add special prayers to ask for a good year. The Gemara records a dispute as to whether this is a prophetically ordained custom or not, but we do know that it traces back to the Beis Hamikdash.
The Mogen Avrohom records: The custom is to stay awake on the night of Hoshana Rabbah. There is a ‘Tikun’ some are accustomed to say, and the Avudraham, writes that one should review the entire Torah from beginning to end. Many places, as per the Arizal, are accustomed to read the entire book of Devarim, which is considered Mishna Torah a review of the other four books. (Presumably this is in preparation for Simchas Torah, the celebration of the completion of the Torah). According to the Arizal one should then recite the entire book of Tehillim. Some have a custom to actually read this from a Torah Scroll; others have Halachic objections to reading from a Torah without the proper blessings etc.
Many others are accustomed to just study Torah, any Torah, on the night of Hoshana Rabbah. Many shuls offer shiurim and classes for those who are interested.
Some men go to the Mikvah, The Pesukei D’zimrah for Yom Tov and Shabbos is recited with two important changes. A) Mizmor L’Todah is added and B) Nishmas is omitted. The Chazzan wears a kittel. The rest of Davening proceeds as Chol Hamoed.
The Shulchon Aruch brings a Minhag to loosen the bindings of the Lulav. They should still remain tied but loosened on the top part of the Lulav. There is some discussion as to when precisely to do this; it seems that at least for the blessing on the Lulav it should still be tied as usual.
As mentioned, during Hoshanos we circle the Bimah seven times instead of the usual one. In some congregations they blow the Shofar after each circuit.
We then return to our seats and proceed with the various tefillos for rain and sustenance. At some point during this exercise we exchange the Lulav for the Hoshana bundle.
The consensus of the Poskim and the Arizal is that one should never holds the Lulav and the Hoshanos together. There are four opinions as to when the exchange happens:
1) Rema writes that we make the switch when we begin the prayers for water (commonly understood to mean upon returning to our seats).
2) The Shelah writes that one should make the trade before the Taaneh Amunim prayer which is the custom and (or perhaps because) how it is printed in most Sidurim.
3) The Taz recommends switching at the very end right before ‘Kol Mevaser’, and
4) the Arizal will have you holding the Lulav until after the Kaddish and only then switching and immediately proceeding with the banging.
The Rema writes that the bundle is waved, just as the Lulav is waved. The Aruch Hashulchan says that although this is not our minhag one should wave their Hoshana bundle a little bit so as to fulfill the Rema.
When to Bang: Some bang immediately before the final Kaddish, Some in the middle of Kaddish before Tiskabel and some after the end of Kaddish which was the Minhag of the Arizal and is quoted by the Baer Haitiv.
How to bang: The Mechaber is very laissez-faire about this. He says that you bang two or three times, on the floor or on vessels. The Arizal says to bang specifically on the floor five times. This signifies that you are ‘burying’ the judgment. In fact the Ben Ish Chai writes that it must be specifically unpaved, virgin earth. There is however an advantage to banging on vessels for they cause the leaves to fall off which symbolizes shredding the decrees. Therefore the Pri Megadim and the Mishna Berura recommend following the Arizal, and then continuing to bang on vessels until some of the leaves fall off. To continue banging until all the leaves fall off is, in the words of the Chaye Adam, childish gleeful play.
The Hoshana Bundle
The minimum shiur for the Hoshanos is one stalk with one leaf on it. The Rema however refers to doing so as uncouth and recommends procuring beautiful Hoshanos.
Halachically three Aravos are recommended; the Arizal recommended using five branches. The Levush is of the opinion that there should be seven branches. The common custom is to have five branches in the bundle.
The bundle is often tied together with strips of Lulav or even rubber bands (as per the Magen Avrohom) or strips of Aravah itself (as per the Pri Migadim). There exists a Minhag not to tie them at all as well.
Some have a custom to obtain a bundle for every member of their family. There are various opinions as to the propriety of recycling Hoshana bundles; it seems that halachically as long as the leaves are still attached it would be ok.
Disposal: There is a custom to save the Hoshanos as kindling for the Matzah baking. The custom to throw the Hoshanos on top of the Aron HaKodesh is of dubious origins, some felt it should not be done as it is a bizayon of the Mitzvah, and others felt it was consistently in the spirit of banging them on the ground.
As an aside, the custom for pregnant women to bite the pitom off the Esrog is brought in the Nazir Shimshon to Mesechta Sukkah. It is heavily attacked by the Mekor Chaim (author of the Chavos Yair) who writes that thankfully this Minhag has already been stopped by the Tzenah Urenah and it should not be done. At the very least, it should not be done until after Simchas Torah according to all opinions.
It is customary to have a festive meal on Hoshana Rabbah. Traditionally Kreplach are served as is the custom on Purim and Erev Yom Kippur. This meal should not take place after Mincha Ketanah, (9 Halachic hours into the day) and preferably should begin before Chatzos (Halachic midday).