I love to see new roots emerging like that. It makes me feel like I'm doing something right......and I like that feeling. The rain water is different from what I do. I use water from a nearby stream and R.O. water. However, I used to use rain water and if I had the means to collect it now, I'd perfer to use it exclusively. Rain water has always produced the best plants and flowers for me. There's something about it that seems to work like magic on the plants.