When do I change the time to 12/12 thanks

A customer has a question and I hope we can get some opinions on it, thanks

my seedlings now have there first leaves and I have my 300watt led full spectrum light on an 18 on an 6 off when do I change the time to 12/12 thanks

Idealy a seedling needs 4weeks veg time atleast to be switched to 12/12.
The longer the veg time the bigger the plant, also if your going to be Topping/Fimming/stressing the plant in anyway it will need tome to recover thus making the veg time longer…

Hope this helps :slight_smile: and welcome :slight_smile:

If you have autos if you choose you can leave them on 18 6 start to finish. Good luck

When your plant is half as tall as you want it to be, switch the light to 12/12.

Dunno what strain you are growing, but, general rule is…plant will double in vertical height in two weeks after being put on 12/12 flower schedule.
How to decide? take available height of grow tent, subtract the depth of the light and supporting gear, subtract the height of containers…now you have actual grow space…subtract 18 to 24" for clearing the lights…AND…THAT IS HOW MUCH VERTICAL SPACE YOU HAVE FOR A PLANT.

Plan accordingly