There is no definitive answer to this question as it depends on a number of factors, such as the type of soil, the climate, and the size of the plant. However, as a general rule, it is best to water your Tulsi plant every other day or every three days. If the soil is particularly dry or the weather is hot, you may need to water more frequently. Conversely, if the soil is moist or the weather is cooler, you can water less often. Ultimately, you will need to use your judgement to determine how often to water your Tulsi plant.