Zuzu, another reason the grocery store (Poulsen, Parade) minis are tough to grow is they only sell them in the winter when we can't plant them outside. I usually pick up 4 or 5 pots of them the week after valentine's day, and they are either dried out, full of spider mites, or soggy with mildew. i never thought about the planting medium as part of the problem! That makes perfect sense.
The challenge is keeping them growing indoors until we can plant them out. I keep them in the sunroom, which has correct humidity and temp, but really I think they need to be under lights.
Boy if i could find them when the weather was warm, I would plant beds full of them, because they are much easier to care for than full size roses. Guess I should say they are NOT tough to grow....they are easy to grow...just not indoors.
