What up Big S, Spider has a great answer . You could also just veg the plant for 3-4 weeks, top it often, and then take clones before putting the hopeful mother under 12/12 . If it turns out to be a male, your work would be for nuthin ! Unless you want to collect pollen. But if it's a female, now you have female clones in veg, and the mother to flower out, to see how "fire" she really is ! GL