For seeds to germinate, you need to keep the growing soil damp but not too wet. To conserve moisture, you can cover the container with clear plastic until seeds germinate. Once seeds sprout, do not miss a watering. Unlike established plants, seedlings do not have an extensive root system they will die if soil dries out. At the same time, it is important not to overwater and let seedlings sit in water. Learning how to water seedlings is vital for success.