I've read that it takes the same to mature regardless of doing 18/6 or a straight 12/12 from seed. The difference is 18/6 gives you a bushy tree with multiple bud sites where as straight 12/12 from seed gives you smaller plants that are generally just one big main cola. Is your max height 90cm? If so then I would maybe do 12/12 just to keep those plants stunted unless you plan on doing some LST. Depends what size pots your using too. Smaller pots= smaller plants.
Peace.
That is incorrect from my experience.
The plants won't be smaller, I've currently got one on the go which is 42" tall, and in my last grow I had one which was 58" tall. The 58" was in an 8litre pot and the 42" is currently in a 5litre pot.
A lot of the plants still grow like Christmas trees in 12/12 from seed, some will not but most will.
If you have the correct products to use on your seeds, you may find this being faster than growing auto flowers, especially when using quick flowering indica dom genetics.(11-14 weeks from seed is usually the prime window to chop them down)
In a nutshell, 12/12 from seed is good for those who want quick results with out a loss in potency, for those want to save on the energy bills and for those that would like to get a perpetual system on the go.
Edit: This is all from my personal experience, others will no doubt have different experiences than me, so in this case, it's all a matter of opinion, I don't wish to start an argument or anything.
