Many Christians pray the rosary out of devotion to their faith, to beseech the mother Mary or to seek blessing, forgiveness or peace. When a rosary is taken to be blessed by a priest, the rosary beads are bestowed with the blessing of the Church, meaning that as you pray the rosary, your prayers are strengthened with the prayers of the Church. In addition, a priest's blessing will also impart rosary beads with an indulgence, which means that as you pray the rosary for forgiveness, you become absolved from punishment for your sins. Only a priest has the power to bless a rosary with these kinds of special spiritual help. However, you can bless your own rosary yourself with Holy water to bestow the beads with spiritual grace.
Take your rosary with you to church.
Bring your rosary to the Holy water basin that is used for dipping the fingers and blessing yourself, usually located near the church entrance. Place a few fingers into the holy water and sprinkle a few drops of holy water over your rosary.
Say a personal prayer evoking God's blessing or read a short blessing verse from the bible.
A supply of holy water is blessed for the church each year on Easter Sunday. You can obtain some Holy water from your parish priest, without charge. Treat your blessed rosary with respect and care, since it is now a sacramental object. Store it in a case and do not wear, hang, drop or toss it around.