I would not try to second-guess soils and ingredients. Just get an ordinary, inexpensive potting mix that people in Norway use to grow houseplants. I'm going to assume that any commercial potting soil will contain enough nutrients to get started. Later on, if you see nutrient deficiencies, you can consider fertilizers.Strange, I believe Miracle-Gro Organic Choice potting mix consist of a blend of sphagnum peat moss, composted bark fines and natural fertilizer. That`s why I tried to find something similar here in Norway.