My mother passed away on יז אדר, and we want to set the stone on י ניסן, is this allowed. We have family coming from abroad for Pesach, including my mothers sister, who would like to be there, and this is the reason that we want to set the stone after the shloshim. I have been told that one can not set a stone during ניסן. Thank you for your help

There are Minhagim that one does not visit a cemetary during the month of Nissan. For a Shloshim one can visit the Kever but one should not eulogize. Rabbi Binyamin Bamberger