Autos and light cycle

I have buying my seeds from ILGM. No complaints at all. I have not tried their guarantee of a new seed if any do not germinate. Mostly because that does not occur at anywhere near a high percentage. I’m not a new grower but I know pretty much about The Plant - have been growing since 1974. A peep can still learn something every day. My question is this as I have never grown autos: Will autos do as well, or almost as well, on a 12/12 light cycle vs an 18/6 light cycle and what is the best par level? Inside growing space is at a premium for me and I’m considering putting the autos with flowering full size plants. I try to keep the canopy at the top between 900-1,000 par. I’ve heard that The Plant will grow at it’s maximum genetic and environmental capability at this par level. Above that a peep needs to introduce CO2 and it’s prohibitively expensive. I seldom have any flowering plant below 700 par. Will an autoflower do well on 12/12 light cycle and do the lights need to be turned up that high?

Welcome to the forum.

There isn’t much difference in total lighting needs between an auto and a photo.

Also ineffective. Cannabis requires PPFD well above 1,000 for the plant to use the extra CO2. It also requires a closed environment and is best used in hydro applications where higher nute levels can be pushed.

A great level for any form of cannabis.

DLI is very useful for ensuring that you are meeting the plant’s needs for productive growth.


With autos you just leave th on a 20/4 or a 18/6 you dont have to flip them to a 12/12