It is forbidden to enter a cemetery, or to come within four Amot of a grave, while one’s Sisit are exposed or while wearing Tefillin. Public Misva observance in close proximity to a grave is an insult to the deceased, as it appears as though one taunts the deceased who no longer has the opportunity to perform Misvot. One is therefore not permitted to display his Sisit or wear Tefillin in a cemetery or near a grave. Likewise, it is forbidden to study Torah or pray within four Amot of a grave. One may, however, speak words of Torah or Hit’orerut (religious inspiration), or recite Tehillim, near the grave for the purpose of bringing merit to the deceased’s soul. Sephardic custom similarly allows reciting Kaddish for the deceased by his grave.
One must conduct himself with respect and decorum in a cemetery. Frivolity and laughter are forbidden in a cemetery. Halacha also forbids using the cemetery in a disrespectful manner, such as by bringing animals to graze there, or running an irrigation system through it. One may not eat or drink in a cemetery, even if his intention is to recite Berachot to benefit the soul of the deceased, as this is disrespectful. Smoking in a cemetery is likewise forbidden. One may not sit or step on a grave.
A number of sources (Eliyahu Rabba 224:7, Kaf Ha’haim Sofer – Orah Haim 224:41) record the practice to place a small stone or piece of grass on the grave before leaving the cemetery, as an indication of, or testament to, one’s visit to the grave. Others, however, claim that one specifically should not place anything on a grave, as this is disrespectful. This was the custom of the Kabbalist Rabbi Sulman Musafi.
Summary: It is forbidden to publicly perform Misvot in a cemetery, but one may speak words of Torah or recite Tehillim in a cemetery to benefit the deceased’s soul. One must conduct himself respectfully and reverently in a cemetery; joking, eating, drinking and smoking are forbidden.
