Super Skunk, Gold leaf, GDP and White Widow Fem plants flowering too soon

From a fellow grower: They ordered Super Skunk , Gold leaf, GDP and White, Widow, fem seeds, grown in a greenhouse which started flowering early, My plants are only 6weeks and 18hrs of light and there ALL BUDDING…Is this a lighting issue?

I would double check the timer if it’s not on natural daylight schedule, or you don’t have enough light to keep them in veg in the green house.