There can be several reasons why a Tulsi plant may suddenly wilt and die. Some of the most common causes include: 1. Lack of water: If the plant does not receive enough water, it will start to wilt and eventually die. Make sure to keep the soil moist at all times. 2. Overwatering: On the other hand, if the plant is overwatered, it can also lead to its death. When watering Tulsi plants, make sure that the soil is only slightly damp. Allow the topsoil to dry out completely before watering again. 3. Pests and diseases: Pests and diseases can also kill a Tulsi plant. Check the plant regularly for any signs of pests or diseases and take appropriate action immediately. 4. Extreme weather conditions: Extremely hot or cold weather conditions can also be fatal for Tulsi plants. If the temperature drops below 10 degrees Celsius, the plant will start to wilt and die. Similarly, if the temperature rises above 40 degrees Celsius, the plant will also perish. 5. Lack of sunlight: Tulsi plants need at least 6 hours of sunlight every day in order to thrive. If the plant does not receive enough sunlight, it will start to wilt and eventually die.