I'm trying to get the soil my gardenias in more acidic. I have been giving it Miracle Gro for acid loving plants, but I find that it's still hovering around 7. I would like to get it to at least 6. If I feed it weekly, would that be too much? It is doing well and is in a container that came from the nursery. I bought it over a month ago and it's full of buds at the moment.