Fast flowering photoperiod CBD strains are crosses that keep the size and yield of a normal photoperiod plant but finish one to two weeks earlier, which can make the difference between a harvest and a mouldy failure at northern latitudes. They are not autoflowers and still need the light change to bloom. The finishing date estimates on https://calmcbdseeds.com are given by latitude band, so growers in Scandinavia or Canada can see which lines realistically complete outdoors. This category has become my default for open ground in a short summer.