Photo-period cannabis seeds sprout in spring, grow in long summer days, and flower in the fall with shorter days. Indoor growers often keep their vegetative lighting at 18:6 (18 hours of light, and 6 of darkness). When the plants reach the desired size and training, plants are then put to flower by switching the lighting to a 12:12 schedule (12 hours of light, and 12 hours of true dark). For more info on growing photo-period cannabis do check out my post Growing Cannabis Outside in Canada.
When it comes to Auto-Flower varieties, the life-cycle from seed to flower is automatic based on age, and not regulated by light schedule. Auto-flowers like light! For indoor growers, this means you can keep them in with vegetative photo-periods plants using 18:6 lighting! Auto-Flowers tend to be a quicker and smaller with some strains harvesting in only 10-12 weeks from seed! Auto-Flower is an option when 12:12 lighting is not, or those living further north with a much short outdoor season.
This brings me to Feminised vs Regular seeds. Regular seeds will have both male and female genetics, growing a mix of both. The males are identified early and removed before producing pollen, keeping the desired un-pollinated ladies. Do check out my post on Sexing Cannabis – Females, Males, and Hermaphrodites! Feminized seeds are made to be just that – female. These seeds remove the need to sex your plants.