Tulsi, Ocimum sanctum, is native to tropical Asia, and is believed to have its origins in India. The traditional holy basil plant readily grows wild in many African and Asian regions. The bushy shrub is easily cultivated from either seed or cuttings, and is typically grown as a potted annual. Typically undemanding, these plants ask for little more than hot, sunny weather and rich, well-draining soil. Although all plant parts are used for religious and medicinal purposes, the leaves are what's most commonly harvested. Tulsi is ready to harvest after about 4 months from the time it sprouts.
Pinch stem tips back just above the second set of leaves when your young tulsi plant is 5-6 inches tall. This will encourage branching and fullness, thereby increasing your harvests to come.
Watch the tulsi closely for the formation of buds, when the plant is about 4-5 months old. Cut new growth stems back to 3 or 4 leaf nodes to harvest them.
Open a large brown paper grocery bag. Fold the sides down halfway, creating a paper basket. Place the cut tulsi stems in the bottom of the basket to a depth of about 2 inches. Store the basket of stems in a very warm, dry spot out of direct light. Toss the stems 2-3 times daily to help them air for 1-2 weeks until they're crispy dry, like corn flakes.
Pinch a dried stem between your thumb and forefinger and zip along its length, popping the leaves off. Toss the stems onto your compost heap.
Store the leaves in a clean, dry glass jar in a cool, dark spot out of light for up to a year.
Harvest again when the tulsi plant's stems have grown another 6 inches. You can expect two to four good harvests before frost.