Bonsai trees thrive in specific temperature and humidity ranges. Most indoor bonsai species prefer temperatures between 60-75°F (15-24°C). Avoid placing your built-in bonsai garden near drafts or heating/cooling vents. To maintain the required humidity levels, you can use a humidity tray filled with water or mist the foliage regularly. This will help prevent the bonsai from drying out in dry indoor environments.