Hey Gerard. Yes, I’ve put in Wildflower seeds in my roof as well before the rainy season starts and it does well… if you have access to the course, I go into detail about how I do drainage for tne roof. Are you building a round or square cobin? If it is round, a gutter is a bit more challenging, but if it’s square it is a bit more straightforward. When it’s round, I create a slope to encourage the water to drain out of drainage holes I drill through the roof and then the water just goes straight down and then away from the structure as I build on a little raised mound.