whats the difference? and the pros and cons to each one?

18 hours

pros
saves $ on electric bill
allows machinery to cool off
lets plants sleep/rest

24 hours

pros
Some people say you get exrta growth

well ive kinda done both 24 hours basically meens its constantly doing phototsynthesis and growing gradually and 18 is i think better because that way in the 6 hours of darkness in has time to use its energy for growing rather that photosynthesis and it will not hit ur electric bill like a ton of bricks haha. yeah but in its dark hours is when it will grow best. but ive done both and they work fine eether way so do wat u want but me personally would go with 18 on 6 off

hmmm yeah what you guys are saying both make sense, but in my mind there's a contradiction hope you guys can clear it out for me: if plants need sleep and the 6 hour of darkness is good for their growth, then how come the 24hr cycle yields more plant growth?

maybe 24hrs is better for the early veggie stage whereas 18 is better for just before floweing?

btw i'm still in the early stages and electricity isnt a problem to me right now cus i'm still using the CFLs

The amount of time your garden should be exposed to lighting depends on what 'cycle' your garden is in:

The 'Vegetative Cycle' of your garden starts with the sprout of the seedlings and can be continued indefinitely. In the veg cycle your garden will require a minimum of 16-18 hours of light and 6-8 hours of darkness daily. Since a given amount of light can only do so much, equal production can be realized in a smaller space with less plants, where the light is concentrated and the plants can grow more efficiently. Using more light helps additional co2 uptake.

Since a plant can be kept in the 'Veg cycle' indefinately, many growers cultivate 'Mother' plants. This plant is used for clone starts and never produces buds, only new growth.


The 'Flower Cycle' or 'Bud cycle' is typically equal amounts of light and dark, 12 hours on, 12 hours off or 12/12. This produces a change in the plants metabolism simulating Fall, shorter days....less light.

This is the cycle that the plants will show their sex. Usually, you'll be able to determine the sex within the first 2 weeks of 12/12. By the 3rd week most plants have developed healthy bud sites or pollen sacks.
The plants will continue on the 12/12 cycle until harvest.

can you realistically keep a plant in the veg cycle indefinitely?

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- durban poison x skunk #1 & california orange

Easily...that's the whole premise behind keeping houseplants.

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I use the 24h light cycle for the first 3 weeks of veg , a week 18/6 and then 12/12 . this has worked great for me as i believe in matureing the roots and plant quickly before the flowering cycle , others may disagree .

I just compromise at 4/20. lol

roots mature faster in the dark when the plant is not putting its energy into photosynthetic tasks. 18/6 provides a more healthy root base imo.

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shower cubicle grow: lowryder #2 & pure thai
http://www.rollitup.org/grow-journal...le-grow-6.html

new grow: seedsman skunk, hashberry & white russian
http://www.rollitup.org/grow-journal...tml#post222036