Growing Cardamom

Can cardamom be grown in zone 4 (eastern-central Quebec)? What is the germination period and when is it best harvested.

Cardamom is not hardy in most of North America. It must be grown as a greenhouse plant or in a bright window in the house. It is a slow and sporadic germinator, meaning that a few seedlings come up at a time, over several months. It also benefits from bottom heat, but even so, the germination rate is generally below 50%.
Cardamom seeds form in pods which develop after flowering. It is not a given that cardamom plants will flower; it depends conditions such as light and temperature and on the age of the plants, so one should automatically assume that a harvest will be possible from indoor grown plants. It may take some experimentation to get the conditions right, and several years, before flowers develop and seeds form.