When someone dies here in Sudan, the family of the deceased including women and children visit the grave after forty days and open the grave. They have seeds of corn with them, which they scatter over the deceased. They also I think throw stones on the deceased. Is it permissible for women to visit graves?
This is a Bid`ah (innovation in religion) for which there is no basis in the Shari`ah (Islamic law). Throwing seeds, perfume, and clothes into the grave are all reprehensible actions for which there is no basis. The grave should not be opened unless there is a good reason for doing so, such as forgetting some tools like shovels by the workers, so it may be opened for that reason, or if one of them has dropped something important, so the grave may be opened to retrieve it. But opening it to scatter seeds or clothes and the like is not permissible.
Women should not visit graves, because the Prophet (peace be upon him) cursed women who visit graves. That was narrated from Abu Hurayrah, Ibn `Abbas and Hassan ibn Thabit (may Allah be pleased with them all).
It is not permissible for women to visit graves but it is prescribed for men, because the Prophet (peace be upon him) said: "Visit the graves, for they remind you of the Hereafter." (Related by Muslim in his Sahih (authentic) Book).