Auto-flowering cannabis seeds are seeds that flower on their own in 2-4 weeks. In order to flower, the normal feminized Indica and Sativa species must be exposed to inside lighting for 12 hours directly after sprouting. They wouldn’t bloom outdoors, because the daylight hours diminish during this season.
Auto-flowering species are Indica or Sativa plants crossbred with Ruderalis, a type of cannabis that grows in areas where summer is very short but has many hours of daylight, from 22 to 24 per day. Ruderalis flowers automatically in a very short period (generally from 2 to 4 weeks).