For the first time I started growing hosta from seeds. The seedlings grew to about 2 inches when I transplanted them from the starter mix to 3 inch pots. They are now about 4 to 6 inches tall now. When should I transplant them to larger pots like 6 inch pots. I assume I will need to keep them indoors through out the winter and plant in the ground in the spring. Does that seem appropriate? Thanks for your feedback.