It is possible to grow artichokes in Canada! We just need to grow them as annuals. As you need 90-100 frost free days to successfully grow them, start seed indoors in February in 4" containers. Transplant out after risk of frost has passed and soil has warmed (seedlings will be 8-10" or 20-25cm tall). As plants tend to grow quite large best to space them 3-4' apart. Artichokes can be a tricky plant to start, ensure you plant a few extra seeds than plants you want to harvest and use lots of nutrient rich fertilizer like Neptunes Harvest fish fertilizers and kelp meal.