Marijuana Plants Flowers After Light Wwitch From 24 to 18 hours

Cannabis flowers 18 hours lightI have been growing these Jack Herer plants and I had mostly kept them under 24-hours of light. Then someone told me that was a bad idea so I shifted to an 18/6 cycle. After just a week, the marijuana plants had started to reveal their sex and their growth began to slow. I’m hoping to keep them in vegetative state to maximize their growth. Will keeping them on 18/6 allow the marijuana to revert to vegetative growth? Or will that cause problems when I switch them to a 12/12 flowering regimen? What’s the best way to get them back to vegetative state?

Getting the marijuana plants back to complete vegetative growth requires a return to the 24-hour light cycle.

When you shift to 18 hours of light, the plants get nearer to the critical amount of darkness needed for flowering. Even so, it takes a little bit longer to get them fully into the flowering state and they will continue in vegetative growth even while producing flowers. This ambiguous state continues until they adjust to the new regimen.

When the regimen shifts to a 12/12 cycle, the marijuana plants will have no trouble entering the flowering stage. Jack Flash plants actually flower better under around 14 hours of light. This might produce longer ripening times, but you will get much larger yields for your patience.


I grow all my plants on a 18/6 cycle, and flower at 12/12. don’t play with the light cycles to much. you run the risk of stressing your plants and can end up with hermaphrodites. I know a few people that push plants at 24 hours straight light, but I don’t ever do that. I feel plants like anything else need to have a period to relax. The big take away from this is to set a cycle and hold to it.