Thanks for the tips, mates. I didn't have to dig far to find the seed case. They look like they're ready to pop! I dug them out so that the seed case is just barely penetrating the surface. I switched from the HPS to a single T5 and a heating mat. I know seeds need to be in the dark to germinate, but I also know that they seek light when they sprout. When should you turn a light on above them?