that's indeed a good plan for growing outdoors in your conditions at your 47N latitude @Emeraldo
Force the flowering by providing in August (or even July if you can) a few hours of extra darkness per day when the summer sun is still strong, then stop the light dep around Sept with a similar (as much as possible) photoperiod, to let them finally finish under naural photoperiod.
Force the flowering by providing in August (or even July if you can) a few hours of extra darkness per day when the summer sun is still strong, then stop the light dep around Sept with a similar (as much as possible) photoperiod, to let them finally finish under naural photoperiod.