it is somewhat strain dependant some will flower with as little as 10 1/2 hours of darkness some may need 11 hours of darkness to flower but all you need is a mature plant or clone and place it out early enough in the spring.
it would be very hard for someone living very far north to do without a greenhouse due to colder weather and increased hours of light they would need to even get an earlier start than you did.
spring harvest do not usually yield much compared to a fall harvest so if your buying seeds best bet is to start earlier indoors like jan 1 and veg until they show preflowers and then clone so you are only placing out females and you get alot more plants to work with out of 1 pack of seeds.