24 hr. lighting versus 18 hr. lighting

24hr light cycle: will cause taller plant on the whole as more light is available
18hr cycle: causes stockier plant

I prefer 18hrs from a week old 24hrs from seed till then.

Originally Posted by misanthropeaic

Can anyone share their knowledge on 24 hr. lighting vs. 18 hr. lighting? Why do some say it's better to have a period of darkness and why do some say 24 hrs. of light is better. Can anyone back their wisdom with scientific fact?

I've tried it both ways and it's not that much of a big deal however you do it so now I start off 24 and work my way to 18 I think people like 18 more because it's more like outside

im running a 24 right now and almost want to switch to 18-6 just to save that extra dollar on the power bill.

18hrs is the best option in my opinion because I believe plants need to rest and an 18hr cycle has always worked very well for me and many others. I dont need my plants to grow any taller than they do already so I say ''if it aint broke then dont fix it'' lol. I use HPS lights so I have no experience with using others like fluros etc so there may be a difference when growing under them but I would never put my plants on 24hrs under my 600 watt HPS.

Originally Posted by sirus420

im running a 24 right now and almost want to switch to 18-6 just to save that extra dollar on the power bill.

Ahh yes the power bill, I forgot about that aswell. When using high wattage HPS lights it would add more $$$ to the power bill which I dont want.

well my bigger one is 6 weeks and the other is like 3, would it hurt them to change it to 18/6?

i have had my plants under my 400 watt hps and surrounded by 3 100 watt hps lamps for side light. i leave them under there for 24 hours a day. they been under it for months with no break. now that i have seen the growth, last night i decided to give the 18 hours a go. one benefit i can see coming is a little break on my electric bill. id really like to put one in 24 hours and one in 18 hours light and video tape the difference. one thing i didnt do last time that im deffinitly doing this time is keeping a journal on feeding. i started my first clones ever today, and im wondering if i need to gie them a dark period....anyone? 24 hours light for a clone or do they need a break. as far as i can tell all the dark does is cause them to stretch and grow taller...i lst and suppercropp to keep mine short and bushy anyway.

Cannabis is a c3 plant, meaning it does not need a period of rest at night. There was a study (ill try to find it) that compared 18/6, 20/4, and 24/0. there was not much of a difference in the 24/0 and the 18/6, the one that did slightly better was the 20/4.