24 hr. lighting versus 18 hr. lighting

BadDog40

Well-Known Member
24/0 will make plants grow faster, but I think the general consensus is not so much to justify the extra electricity use. I personally like 22/2.
 

wannabee

Well-Known Member
Could you please tell me where you found 100 watt hps lights. I need some good flowering lights soon. Thanks.
 

Nocturn3

Well-Known Member
I've posted the following in a few threads about this subject, so I may as well post it here as well, since it's relevant. This is a post by OT1 regarding vegging times:


Originally Posted by oldtimer1
We did a lot of experiments with light times a few years back using known sat and sat dom clone lines.

With Vegging ie under hid lights.

20/4 produced the most sturdy growth and the most bulk. Best final yield, taken as 100%.
22/2 Less of both. yield 88%
18/6 Studier than 22/2 but slightly less bulk. yield 87%
24/0 Much lighter in all aspects than 18/6. Yield 79%
16/8 The weediest plants. yield 67%

Plants vegged to final pots under fluorescents at 20w per sq ft on 18/6 yield 49%

Have not tried 36 hrs dark but did try 48 hrs from 18/6 veg. The final yield was down between 15 and 20% by var the pure sats the biggest loss in final weight and caused the odd herm, [sats] it did reduce the flowering time by 5 to 8 days.

For the mum lines we have 20/4 to 12/12 gives the best crop weight and bud quality, really thats all I’m interested in.
Taken from here.

.
 

lampshade

Well-Known Member
I've posted the following in a few threads about this subject, so I may as well post it here as well, since it's relevant. This is a post by OT1 regarding vegging times:


Originally Posted by oldtimer1
Taken from here.

.
Nocturne thank you so much. That looks exactly like the study i was trying to find.
 

Brick Top

New Member
This is by no means a complete, technical explanation of Botany, rather it’s an understanding of the basic principles.

Many times I’ve seen in posts that “roots grow during the dark.”. If this were true, the 24/0 photoperiod would result in a plant with a tiny root structure, if one at all! We know this is not the case - so how does it actually work?

To simplify things, lets use an analogy. Try to think of a plant as a building… one constantly under construction. The plant needs raw materials, (fertilizers and water), and energy (light) in order to “build itself”. The raw materials are the “bricks and mortar” of the building. The energy is the workers, vehicles and power tools used to assemble the building.

The Plant is capable of storing some raw materials and some energy for use later, but the amount is limited...think of a warehouse and a battery.

During the day, (Lights ON) the plant is collecting and storing light energy, and is using and storing raw materials. The plant is stockpiling raw material, and is charging it’s batteries… it is ALSO using raw materials and using the energy it is collecting. It’s building itself, literally putting itself together.

During the day however, the plant is not as efficient at building itself, as it is at night (lights OFF.) It can build itself, but not as quickly.

While the lights are OFF, the plant is using energy and raw materials to build itself…. the plant is more efficiently using the raw materials that it stored during the day. The plant is better at transporting and assembling the raw materials.

The bad news: since there is no light energy, the plant must rely on energy it stored while the lights were ON (its stored energy). (Essentially, the plant is running on batteries, and using raw material from the warehouse.)

There is no light energy to collect. Since the plant needs energy to absorb more raw materials, it is easier for the plant to use raw materials that it stored during the day than it is to absorb raw materials through its roots.

Although the plant IS capable of “doing it all” with the lights on, (Collect, store and use energy & raw materials) it does a better job of actually doing the work (using the energy and raw material) while the lights are out. During the dark however, it relies solely on its limited supply of stored energy and stored raw material.

One last thing to remember is the fact that a plant will always strive to maintain a balance between the size of its roots and the size of its canopy (Leaf mass.) The roots must be big enough to supply as much raw materials as the canopy can use, and the canopy must be big enough to provide the energy required to store those raw materials….

Trim the roots on a healthy plant, and canopy growth will slow to a crawl until the roots have grown big enough to again support the canopy.

Trim the TOP of a healthy plant, and root growth will slow similarly, until the canopy has grown big enough to again support the roots.

If the plant is already in balance, the canopy and the roots will grow at the same rate.

If you actually measured them several times daily over several days, you’d notice that they actually DO get bigger at night, but roots and canopy at the same rate, unless either has been trimmed, and as long as the “batteries” hold out.
 

lampshade

Well-Known Member
This is by no means a complete, technical explanation of Botany, rather it’s an understanding of the basic principles.

Many times I’ve seen in posts that “roots grow during the dark.”. If this were true, the 24/0 photoperiod would result in a plant with a tiny root structure, if one at all! We know this is not the case - so how does it actually work?

To simplify things, lets use an analogy. Try to think of a plant as a building… one constantly under construction. The plant needs raw materials, (fertilizers and water), and energy (light) in order to “build itself”. The raw materials are the “bricks and mortar” of the building. The energy is the workers, vehicles and power tools used to assemble the building.

The Plant is capable of storing some raw materials and some energy for use later, but the amount is limited...think of a warehouse and a battery.

During the day, (Lights ON) the plant is collecting and storing light energy, and is using and storing raw materials. The plant is stockpiling raw material, and is charging it’s batteries… it is ALSO using raw materials and using the energy it is collecting. It’s building itself, literally putting itself together.

During the day however, the plant is not as efficient at building itself, as it is at night (lights OFF.) It can build itself, but not as quickly.

While the lights are OFF, the plant is using energy and raw materials to build itself…. the plant is more efficiently using the raw materials that it stored during the day. The plant is better at transporting and assembling the raw materials.

The bad news: since there is no light energy, the plant must rely on energy it stored while the lights were ON (its stored energy). (Essentially, the plant is running on batteries, and using raw material from the warehouse.)

There is no light energy to collect. Since the plant needs energy to absorb more raw materials, it is easier for the plant to use raw materials that it stored during the day than it is to absorb raw materials through its roots.

Although the plant IS capable of “doing it all” with the lights on, (Collect, store and use energy & raw materials) it does a better job of actually doing the work (using the energy and raw material) while the lights are out. During the dark however, it relies solely on its limited supply of stored energy and stored raw material.

One last thing to remember is the fact that a plant will always strive to maintain a balance between the size of its roots and the size of its canopy (Leaf mass.) The roots must be big enough to supply as much raw materials as the canopy can use, and the canopy must be big enough to provide the energy required to store those raw materials….

Trim the roots on a healthy plant, and canopy growth will slow to a crawl until the roots have grown big enough to again support the canopy.

Trim the TOP of a healthy plant, and root growth will slow similarly, until the canopy has grown big enough to again support the roots.

If the plant is already in balance, the canopy and the roots will grow at the same rate.

If you actually measured them several times daily over several days, you’d notice that they actually DO get bigger at night, but roots and canopy at the same rate, unless either has been trimmed, and as long as the “batteries” hold out.
did you copy that from here or is that you
http://www.420magazine.com/forums/how-grow-marijuana/71067-do-roots-really-grow-dark.html
 

Brick Top

New Member

Actually I copied it from an email sent to me a short while back that I saved. I have no idea of where it originally came from.

What I do know is that it is true. My family owns a nursery, trees and bushes, not plants or taking care of kids, and my brother in law, my sister and my niece all have botany degrees and I have asked them about it and they said it is true.
 

lampshade

Well-Known Member
Actually I copied it from an email sent to me a short while back that I saved. I have no idea of where it originally came from.

What I do know is that it is true. My family owns a nursery, trees and bushes, not plants or taking care of kids, and my brother in law, my sister and my niece all have botany degrees and I have asked them about it and they said it is true.
Yes that is true, its just that it was originally posted by a guy named smockeymcpot in 2004. I remember the original posting and the moment i got 1/4 of the way through reading your post i new it was plagiarized. You really should either summarize in your own words or state the source.
Im not bashing you or anything im just saying...
 

Brick Top

New Member
Yes that is true, its just that it was originally posted by a guy named smockeymcpot in 2004. I remember the original posting and the moment i got 1/4 of the way through reading your post i new it was plagiarized. You really should either summarize in your own words or state the source.
Im not bashing you or anything im just saying...

Since I received it in an email I have no idea of who to credit it to and call me lazy but I was not about to rewrite the entire thing putting it into my words. For all I know my friend who sent it originally wrote it and he may have found it on some other herb site since he belongs to several, but not this one, and he may have found it on some other site while researching growing since there are so many sources to be found that are not herb site forums.


In a case like this I do not consider it plagiarizing material since I did not seek out and then use someone else’s material without crediting them.

It was just passing on valid factual information that was sent to me that may or may not have come from some source unknown to me.
 

AfghanBoy

Well-Known Member
i do 18/6, i think the closer you get to the outside environment (in terms of light) the better, and as i live in the UK, we get about half an hour of light a day :))

plus it saves electric
 
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