In winter, Tulasi can suffer taken indoors into dry, heated homes in the west, since she likes humidity. This in turn makes the infamous appearance of spider mites. To keep them away and keep Tulasi happy, spray under her leaves morning and evening. For smaller pots of Tulasi, a sprayer attached to a sink works well.
At the same time, Tulasi doesn’t require much water in winter. The drips afterwards are plenty for weeks. Only if her pot feels light and soil dry, give her a nice drink. Don’t wait until her leaves curl: it puts a strain on her. Best if the watering is followed by a sunny window. In other words, do not water at night, so not to invite soil diseases brewing underneath. I’ve never tried it, but in that case I’ve heard that dried cow dung as a top dressing to soak in can disinfect the soil. Cow dung is naturally antiseptic.
Keep her on a sunny window ledge during the day and remove her in the evenings, so she doesn’t catch a chill.
Caring for tulasi helps us build a relationship with her and pleases Lord Krishna very much.