The Gemara gives instruction on the Beracha of "Asher Yasar Etchem", which is a Beracha that is said when someone visits a cemetery. The Shulchan Aruch on this writes in Orach Hayim siman 224:12 writes, "Ha’Roeh Kivre Yisrael Achar Sheloshim Yom, YeVarech BiShem U’Malchut’. This means that a person should recite the full Beracha of "Asher Yasar Etchem Badin…" when visiting a cemetery whereby his last visit was more than 30 days prior. Additionally, one makes this prayer when revisiting a cemetery within 30 days if a new grave was added. (See Kaf Hachayim ibid:39.)

But there is an interesting question regarding an Onen. A person has the status of ‘Onen’ between the time of death of a close relative and their burial. We learnt that an Onen is exempt from Berachot and Mitzvot. So should the Onen make the Beracha of "Asher Yasar Etchem Badin…" after completion of the burial since after the burial he is obligated in Miztvot? Halacha says he can not say the Beracha. (See Kaf Hachayim ibid:37.) The reason is that when he entered the cemetery he was at that time exempt from the Beracha, and even though he is no longer an Onen, once the body is buried he remains exempt. The requirement to make this Beracha falls upon a person upon entering a cemetery, and an Onen remains exempt in deference to his status upon his arrival.

Halacha also says as brought down in the Kaf Hachayim in siman 224:37, that a person is not required to make the Beracha even if he didn’t visit a cemetery in 30 days if he; i) looked upon the cemetery while walking by, ii) looked upon the cemetery through his car window, or iii) viewed the cemetery through his nearby apartment window.

The Beracha is even made on Shabbat. If for whatever reason a person went into a cemetery on Shabbat, he would make the Beracha. Some Rabbis disagree and feel that it is considered ‘Tziduk Hadin’ and that it is like making a ‘Hashkavah’, which are not proper on Shabbat. However, we follow that it is a Beracha and thus permissible to be said on Shabbat. (See Kaf Hachayim ibid:48)

There are some customs that must be clarified when visiting a cemetery. There is a custom to put flowers on a casket and on a grave. This is not a Jewish custom. It should not be embraced as Minhag Yisrael. Some Rabbis go to the extreme and even say that it is considered, ‘Ub’Hukotehem Lo Telechu’, which means putting flowers may constitute following in the ways of the Goyim. Chacham Ovadia Yoseph in Yabia Omer Helek 3 24:25 does not go that far, but he says that one should refrain from doing such a thing.

The Kaf Hachayim in Hayim VaHesed, perek 24:15 says that it’s a custom to respect the deceased and put a rock or a stone on the coffin as a sign that you were there. But this custom is also in question. Some of the Mekubalim were Makpid not to put the rock. But since the Kaf Hachayim brought it down as a Minhag, one therefore may do such, and would have what to rely on. (See Kaf Hachayim ibid:41.)

Last but not least, Rabbi Yehuda HaChasid brings down that one should not go to the same grave twice in one day. Which means, one should recite all his prayers that he wants to make at a particular grave, and once he leaves he should not come back until the next day. It seems that there’s a Kabalistic basis behind this restriction, or a reason beyond normal logic. Either way, one should refrain from visiting the same grave twice in one day. (See Kaf Hachayim ibid:44.)