lighting change

Gr33n · Feb 16, 2009

since the search on here does not seem to work i was wondering how many hours of light is needed during vegetation. right now my sprout is about 2 inches tall and the lighting i am using now is 24/0. should i switch to 18/6 or keep the 24 cycle on for a while longer? the light i'm using is a 20w.

dirtyoz · Feb 16, 2009

Yeah the search function does suck. But I got it to work by using advanced search then the tag box. Use only one word though.
Good luck

Gr33n · Feb 17, 2009

i got nothing man. didn't work for me

haze2 · Feb 17, 2009

Yo green considering you only have a 20w bulb I would definately leave it on 24/0 its only going to promote it to grow faster than 18/6 oh and make sure you put that light as close as possible a low watt light like that is good for stretching unless you help that.

Gr33n · Feb 17, 2009

haze2 said:
Yo green considering you only have a 20w bulb I would definately leave it on 24/0 its only going to promote it to grow faster than 18/6 oh and make sure you put that light as close as possible a low watt light like that is good for stretching unless you help that.

alright that's what i thought. yeah i have it about 2 inches away from her. she's been growing really nice and steady. wish i could post some pictures but my battery on my camera is dead and i don't know where it is

laserbrn · Feb 17, 2009

Gr33n said:
alright that's what i thought. yeah i have it about 2 inches away from her. she's been growing really nice and steady. wish i could post some pictures but my battery on my camera is dead and i don't know where it is

Lots of different schools of thought on this one. I tend to believe that 24/0 gives more energy to the plant, BUT there is evidence that the plant does most of it's actual growing during the dark cycle.

I can't vouch for the validity of either personally because I haven't tried 18/6, but from what I've heard it's a lot more efficient.

Madhadda · Feb 17, 2009

im currently on 18/6 and i truly believe that plants need their lights off periods too. My plants are on the same light cycle as i am

. 6 hours of sleep, 18 ours of light

Gr33n · Feb 17, 2009

laserbrn said:
I tend to believe that 24/0 gives more energy to the plant, BUT there is evidence that the plant does most of it's actual growing during the dark cycle.

that's what i have been thinking too. i'm going to give 18/6 a shot for the rest of this week. see how it works out

haze2 · Feb 17, 2009

I can say I did 18/6 all the way upto flower just to let my ballast sleep along with my women.

laserbrn · Feb 17, 2009

haze2 said:
I can say I did 18/6 all the way upto flower just to let my ballast sleep along with my women.

There is a lot to be said for this. MH bulbs are famous for failing and bursting if you leave them on for more than a week without a rest. You gotta rest the equipment sometime.

Brick Top · Feb 17, 2009

laserbrn said:
Lots of different schools of thought on this one. I tend to believe that 24/0 gives more energy to the plant, BUT there is evidence that the plant does most of it's actual growing during the dark cycle.

I can't vouch for the validity of either personally because I haven't tried 18/6, but from what I've heard it's a lot more efficient.

Ok .. here I go AGAIN.

When a plant is under light it is multitasking, it is using the energy it is taking in, in numerous ways so it is less efficient at growing.

When in periods of darkness the plant is running off of stored energy, one of the things it does while the lights are on which takes away some of its growth efficiency, storing energy, and the plant is then more efficient at growth.

That is the very short Readers Digest Condensed Version but that is basically how it works and why an 18/6 light cycle is better than a 24/0 light cycle.

So yes in a 24/0 light cycle more energy is taken in but it is used in numerous ways all at once so a lesser percentage of what is taken in goes to growth than during periods of darkness.

That explains why people will at times say things like, oh my gosh, I swear I could tell that my plants shot up overnight. That is because they are more efficient at growth in dark periods and when in the fast growing flowering stage they can and will grow so much overnight that you can visibly notice it at times.

Uncle Ben · Feb 17, 2009

Brick Top said:
Ok .. here I go AGAIN.

When a plant is under light it is multitasking, it is using the energy it is taking in, in numerous ways so it is less efficient at growing.

When in periods of darkness the plant is running off of stored energy, one of the things it does while the lights are on which takes away some of its growth efficiency, storing energy, and the plant is then more efficient at growth.

That is the very short Readers Digest Condensed Version but that is basically how it works and why an 18/6 light cycle is better than a 24/0 light cycle.

So yes in a 24/0 light cycle more energy is taken in but it is used in numerous ways all at once so a lesser percentage of what is taken in goes to growth than during periods of darkness.

That explains why people will at times say things like, oh my gosh, I swear I could tell that my plants shot up overnight. That is because they are more efficient at growth in dark periods and when in the fast growing flowering stage they can and will grow so much overnight that you can visibly notice it at times.

Absolutely! Plants need a rest and experience alot of positive growth changes when they are allowed to rest. A very important factor too is giving them a 15F or better differential between day and night temps.

A 20/4 photoperiod during veg is a good compromise.

UB

haze2 · Feb 17, 2009

Good Information!!

Gr33n · Feb 17, 2009

thanks a lot. that is a lot of good information. i decided to go on 20/4 for a week then i'll switch to 18/6

haze2 · Feb 17, 2009

Indeed sounds good. Keep it greeen.

pennywise619 · Feb 17, 2009

Man I swear this is one of the biggest debates.....

I personally love both 18/6, but if your grow is time sensitive I would def go with 24/0. There is no hard evidence stating that each photo period is better than the other, because each plant grows at different rates, and different ways....

What is a fact is that when plants are introduced to 24/0 ther roots do not develope as well as plants grown under 18/6. Word of advice like someone said on here 20/4 would be your best bet and you would get the best of both worlds.....

haze2 · Feb 17, 2009

I agree..best of both

laserbrn · Feb 18, 2009

haze2 said:
I agree..best of both

I'm going to try this one my next grow. I'm going to grow 20 clones from the same mother and grow 10 under 24/0 and 10 under 18/6. Veg them each for 4 weeks and see the results.

I have some cuttings right now that I'm waiting to root...

Please advise on what information you guys would like to see gathered.

I am planning already on noting root development, growth, and of course the yeild from each when finished.

I'm sure that there some other great measures that I can use also, but I'm tired right now and can't think.

pennywise619 · Feb 18, 2009

laserbrn said:
I'm going to try this one my next grow. I'm going to grow 20 clones from the same mother and grow 10 under 24/0 and 10 under 18/6. Veg them each for 4 weeks and see the results.

I have some cuttings right now that I'm waiting to root...

Please advise on what information you guys would like to see gathered.

I am planning already on noting root development, growth, and of course the yeild from each when finished.

I'm sure that there some other great measures that I can use also, but I'm tired right now and can't think.

I just mainly would love to see the root growth between 18/6 and 24/0, because the best photoperiod for clones is definitly 18/6, because 18/6 promotes root growth evened out with canopy growth. 24/0 is recommend only for canopy growth and slow root growth. So I definitly will be watching this, also are you going hydro so we can see the actual root growth???

laserbrn · Feb 18, 2009

pennywise619 said:
I just mainly would love to see the root growth between 18/6 and 24/0, because the best photoperiod for clones is definitly 18/6, because 18/6 promotes root growth evened out with canopy growth. 24/0 is recommend only for canopy growth and slow root growth. So I definitly will be watching this, also are you going hydro so we can see the actual root growth???

Yes, I will definitely go hydro so that I can see the root development. Wouldn't make much sense you use soil.

I'm pretty excited to see this and really glad I have so many resources now. Are there are any controls people would like to see in place? Such as using the same resevoir, etc? That does pose some challenges, but can make a difference so I'm going to see how I can pull that off.

I was originally going to use two grow rooms as I have them, but I'm trying to figure out a good way to have good controls. I am going to buy another light hood to ensure the lighting is equivalent.

I also don't like one of my light hoods so this was planned before the next run anway.

lighting change

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