Mincha: usual erev Yom Tov tefilla – weekday Shemoneh Esreh with mention of Sukkos. Following the chazzan’s repetition, Kaddish Tiskabbel, Aleinu (Nusach Sefarad say LeDavid Hashem Ori) followed by mourners Kaddish.
Due to Yizkor, which we recite on Shemini Atzeres, we light yahrtzeit candles for the departed souls before we light the Yom Tov candles – which are to be lit twenty minutes before shekiah – at 6:10 p.m. (N.Y.C. E.D.T.).
Maariv: usual tefilla of Shalosh Regalim. We add VaYedabber Moshe before the Shemoneh Esreh of Shalosh Regalim and we make mention of Shemini Atzeres. Kaddish Tiskabbel, Aleinu and LeDavid Hashem Ori. (Nusach Sefarad says LeDavid, following Mincha) and mourners Kaddish recitals.
Minhag Sefarad make the hakafos on the night of Shemini Atzeres as well as the night of Simchas Torah.
Kiddush is Yom Tov text of Shalosh Regalim – Asher bachar banu, mekaddesh Yisrael veHazemanim. Since Shemini Atzeres is considered a new Yom Tov, we add the blessing of Shehecheyanu. However, though most still eat in the sukkah because of sefeka deyoma, lit. “a doubt regarding the day.” Regarding the other days of Sukkos, in reference to the mention or their sacrifices in both the Torah reading and Shemoneh Esreh of Musaf, we treat each day as a doubtful day. We nevertheless do not say the beracha leishev baSukkah as we no longer refer to this Yom Tov as Sukkos. We do continue the custom of substituting honey for salt into which we dip our challah at the blessing of Hamotzi.
Monday morning: Shacharis as usual with the following exceptions: chazzan begins at HaKel instead of at Shochen Ad. The Shemoneh Esreh is that of Shalosh Regalim. Following chazzan’s repetition we say whole Hallel followed by Kaddish Tiskabbel. (Nusach Sefarad then say the Shir shel Yom and LeDavid Hashem Ori and their respective Kaddish recitals.)
We remove two Sifrei Torah from the Ark. We say the Thirteen Middos and Ribbono Shel Olam.
We call 5 aliyos in the first sefer and we read in Parashas Re’eh, Asser Te’asser (Deuteronomy 14:22-16:17). We then place the second sefer next to the first sefer and the Ba’al Keriah recites half Kaddish. We call the Maftir. We read from the second sefer in Parashas Pinchas (Numbers 29:35-39; 30:1)
The Maftir reads the Haftara, Vayehi kechalos Shlomo (I Kings 8:54-66; 9:1).
It is customary in many congregations to schedule a Yizkor appeal, due to the text of the Yizkor prayer – “in the merit of my vowing to give charity on his/her behalf.”
We then say Yizkor and Av Harachamim followed by Ashrei. We return the Sifrei Torah to the Ark. The chazzan dons a kittel and recites half Kaddish to the special Nusach of Geshem.
Musaf: Before we begin the silent Shemoneh Esreh, the gabbai calls out, “Mashiv Haruach U’morid Hageshem” so that we will add this phrase to our silent Shemoneh Esreh as well.
In chazzan’s repetition we recite the prayer for rain in its proper season (Geshem), which he chants to its special nusach. At Vese’arev the Kohanim go up to the duchan. (The Levi’im, or where none are available, the firstborn – bechorim – have washed the Kohanim’s hands). The congregation says Ribbono Shel Olam and Yehi Ratzon. The chazzan then recites Kaddish Tiskabbel.
The Musaf service concludes with Ein K’Elokeinu, Aleinu, Shir shel Yom and LeDavid Hashem Ori (Sefarad already said Shir shel Yom and LeDavid Hashem Ori at the end of Shacharis following Hallel) and their respective Kaddishrecitals. Some congregations conclude with An’im Zemiros and mourners Kaddish.
Mincha: Ashrei, U’va LeTziyyon, half Kaddish. All then say the silent Shemoneh Esreh of Shalosh Regalim. We are careful to include in the beracha of Mechayyeh Hameisim – Mashiv Haruach U’morid Hageshem. If one forgot to include this blessing: If he realized before he uttered the beracha of Ata Kadosh – he is to include it there and then. If, however, he already said Ata Kadosh, he repeats the Amidah from the beginning. Thus, according to Rema (Orach Chayyim 114:9), in order not to utter a blessing in vain, it is proper to repeat thia [at some time earlier in the day] 90 times – “Mashiv Haruach U’morid Hageshem.”
The Mishna Berura (ad loc.) explains that one says…. Rav lehoshia Mashiv Haruach U’morid Hageshem, 90 times. He quotes the Chasam Sofer (Responsa Vol. I 9:20) as well, who opines that one repeats it 101 times, but only if one has said it less than 90 times would he repeat the Shemoneh Esreh.