13. When is the best time to start sowing and what kind of soil do you use?

It is difficult to give an exact specification about the sowing time, as every hobby gardener gains his or her own experience. 

My experience has been that it makes sense to sow the medium-late and late-ripening varieties from the end of January to mid-February at the latest. Otherwise they will no longer ripen, as it is significantly cooler in our latitudes from mid-September and has less sun. 

For all other varieties (early/mid-early) the beginning to the end of March is sufficient. 

It is sown in potting soil. This has few nutrients which in turn stimulates root growth.