Why Do We Worship Tulsi ?
Either in the front, back or central courtyard of most Indian homes there is a tulsi-matham an altar bearing a tulsi plant. In the present day apartments too, many maintain a potted tulsi plant. The lady of the house lights a lamp, waters the plant, worships and circumambulates it. The stem, leaves, seeds, and even the soil, which provides it a base, are considered holy. A tulsi leaf is always placed in the food offered to the Lord. It is also offered to the Lord during poojas especially to Lord Vishnu and His incarnations.
In Sanskrit, tulanaa naasti athaiva tulsi - that which is incomparable (in its qualities) is the tulsi. For Hindus, it is one of the most sacred plants. In fact it is known to be the only thing used in worship which, once used, can be washed and reused in pooja - as it is regarded so self-purifying.
As one story goes, Tulsi was the devoted wife of Shankhachuda, celestial being. She believed that Lord Krishna tricked her into sinning. So she cursed Him to become a stone (shaaligraama). Seeing her devotion and adherence to righteousness, the Lord blessed her saying that she would become the worshipped plant, tulsi that would adorn His head. Also that all offerings would be incomplete without the tulsi leaf - hence the worship of tulsi.
She also symbolizes Goddess Lakshmi, the consort of Lord Vishnu. Those who wish to be righteous and have a happy family worship the tulsi. Tulsi is married to the Lord with all pomp and show as in any wedding. This is because according to another legend, the Lord blessed her to be His consort.
Satyabhama once weighed Lord Krishna against all her legendary wealth. The scales did not balance till a single tulsi leaf was placed along with the wealth on the scale by Rukmini with devotion. Thus the tulsi played the vital role of demonstrating to the world that even a small object offered with devotion means more to the Lord than all the wealth in the world.
The tulsi leaf has great medicinal value and is used to cure various ailments, including the common cold.