Does Deep Daan form part of the Tulsi Vivah sacred ritual?

Yes. The offering of ghee lamps (Deep Daan) is integral to the Tulsi Vivah ceremony and to all the sacred rituals of Kartik Poornima. Lamps are lit during the wedding ceremony itself, placed around the Tulsi-mandap, and offered to the Ganga. The broader context of the lamp-offering tradition — from the Varanasi Dev Deepavali to the Deep Daan at Ayodhya — all flows from and converges on the Karttika month, of which the Tulsi Vivah is the sacred centrepiece.