Primrose seeds do well started in pure Turface. Use a container of suitable size--it does not need to be large. Set the planted container(s) in a flat pan of water to a depth of about 1". P. sieboldii needs a cold period but the others should germinate at about 65-70. There is no reason you cannot put your planted containers outside in a light sheltered place if you wish. Do not put them in direct sun. This is far from the only way to do Primrose seeds. Many other ways are equally successful. For some reason Primroses in Turface do not seem to suffer from damping off or root rots. The seedlings can stay in the Turface until you are ready to put them in their permanent home.