Garbhanyasam is a ritual performed during the construction of Kerala style temples. During the construction the ritual performed below the right side (kattala) frame of door. Garbhanyasam ritual is also performed under the Valiya Balikkallu.
In Garbhanyasam, a square copper vessel is filled with images of tortoise, fish made in gold or other costly items. After purification rituals, the vessel is closed with a lid and is place below the ground as per tantric rituals.
Same procedure performed with stone or sand bricks are known as Ishtikanyasam.
Another holy item that is part of the ritual is the Panchagavya. The liquid panchagavya is filled in a copper kalash is installed after homa and along with sambatavam.
The ritual is usually performed after 7 yamam of night (time after midnight).