Hello Perfectly Perfect ! I will tell you, from what I know. It is kept outside, more for sunlight. It is kept in a tulsi-madam, a lamp is kept in front, kolam is drawn & tusi is worshipped. The olden day belief was that ladies should not touch it during their menstrual cycle. So, keeping it outside the house was suitable. There is nothing wrong in keeping it inside, provided it gets enough sunlight, air etc. Generally, if a tulsi plant is worshipped, the leaves from that are not plucked, to be eaten - well, my knowledge on all these customs is meagre. I am [posting in tamil, below, what is given in a tamil book. Thankyou for the F b. Love, Chithra.