This is one of my most satisfying gardening projects. I start petunias in January the transplant them into hanging baskets in March. They spend the next six weeks growing in the cool greenhouse before moving to their hanging location at the front of our home.
I put in a layer of mix the some pre moistened water saving crystals. Pre moistened is the key word here. If you forget this step, you could see an erupting soil volcano when they finally absorb water!