24 hour lights

Folks, I see lots of peoples using 24 hour veg times. All in good in some situations for a short period of time, but the plant needs some total darkness every day to work on root development.

You will slow root proliferation by using 24 hour lighting, increase your electrical costs, increase the 'wear and tear' on the lighting system and needs rest daily too......

I think you will find that most of the experienced growers have learned there is no additional benefit from 24 hour lighting over 18/6. Save some money, go 18/6 whenever possible.

Yes there are times to go 24, I find I don't ever need them.

My guess is that each strain has a 'sweet spot' of proper light schedule and spectrum, but 18/6 during the growth phase is a good starting point. I much prefer using the 18/6 growth schedule, but there are times when 24/0 is a necessary evil.

Like if there is a problem with other lights being turned on and interupting the dark period, (bathroom light, kitchen light...) or if you can't afford a timer...24/0 is a good temporary option until you can rectify the situation.

Although the lights can provide overnight heat for the little darlings, it can be tricky keeping them hydrated properly, and they just don't perform as well under 24/0. At least not in my experience.

I'm not even positive that 24/0 is a good idea for autoflower strains, but I haven't grown any of those yet.

I just read a 20 page thread on '24 Hour Lighting'...at ICMag. My brain still hurts.....:stoned:

Those big dawg growers will argue 'tooth & nail', over anything...:D

Vegging time should be selected by the grower; to fit the growroom situation....
for heat or cooling problems, light security, etc....
Those problems override concerns about 'ideal' plant growth....IMO

I just realized I have my timer set at 19/5...:wtf:

This subject seems to come up every few months, so let's get at it; :beatdeadhorse: .

Quote:

---

Originally Posted by WashougalWonder

Folks, I see lots of peoples using 24 hour veg times. All in good in some situations for a short period of time, but the plant needs some total darkness every day to work on root development.

---

Sorry 'Wonder, plants don't need darkness to work on root developement. "Roots grow in the dark, but not when it is dark". In fact most "experts" reccomend 24/0, low level blue dominate light to root cuttings. If a plant needed a dark period to "work on root developement" you would not be able to produce clones with this method. ;)

There is a certian amount of cell division that takes place during the dark period, it envolves the root cap grow points, but what it is making is a lubricant for the tap roots for when they go back to growing.

Scientific studies of plants in general and cannabis in particular, shows there is no harm to the plant using 24/0 for vegative growth. Meaning they do a flower stage very normally even after such treatment.

BTW: plants don't "rest" during the dark period, if you study them and what they do you'll find that plants are 24 hour factories.

OM

LOL! one of the great debates! Here's my two cents, I grow from clones in dirt...After allowing the clones to root for 2 weeks under low light, I give them the 18/6 for 3 weeks, and then go 24/0 for 3 weeks then 12/12 for two weeks and then 13/11....so I compromise, I guess. This is the first time at this light schedule, and they are only in 3rd week of flower, today is day 18, but everything is looking pretty good, so far. Yesterday, I noticed trichomes w/o a magnifying glass for the first time and was pleased! Closet grow with 400w mh for veg, hps for flower.

This will get things going.... he he he :lol5:

OldMac, Ya you are right, roots grow in the dark period. I am not stating what I mean again.

The stopping of photosynthesis with the loss of light allows the plant to concentrate on the root system, which I believe grows a stronger plant. As any study can be made to show whatever is desired, it is all a matter of opinion.

I prefer to save the money on the shorter time as I see no benefit in the end result with times other than what I use....18/6 and 12/12.

We should do a whole thread on roots, because what you see above has someplace in the pot down in the dirt. And we thought the human circulatory system was complicated.

Quote:

---

Originally Posted by oldmac

This subject seems to come up every few months, so let's get at it; :beatdeadhorse:
Sorry 'Wonder, plants don't need darkness to work on root developement. "Roots grow in the dark, but not when it is dark". In fact most "experts" reccomend 24/0, low level blue dominate light to root cuttings. If a plant needed a dark period to "work on root developement" you would not be able to produce clones with this method. ;)

---

Just because you can, dosen't mean it's best to do so. Regardless...you're comparing apples to oranges. An unrooted clone is not following the same path, and has different needs, than a healthy seedling.
And again...If a clone performs 'better' under 24 hrs of light, this does not mean it's optimal for an otherwise healthy plant.
If it DOES perform 'better' under a 24/0 schedule, then what happens during the dark period that is disagreeable with an unrooted clone? In other words...if nothing changes at night, why is 24/0 better?

Normal darkness changes the plant phisiology, respiration and transpiration.
Relationship between transpiration and respiration in plants during the dark period
This changes the chemical, (nutrition) mineral, (cell building) and carbon ratios, (O2:CO2 exchange) and can determine proper photosynthesis, transpiration and cell integrity.

A Comparison of Dark Respiration between C3 and C4 Plants

Gonna have to provide some of your researtch info to convince me, OldMac. :thumbsup:

If you Google "plant processes during the dark period" you'll come up with other fine examples of the processes.

The Spice of Life, keeps it Interesting...

After 30 years of Gardening ( mostly non-med ) I find I have a better crop overall with a Dark Period of some sort. Since I'm only Veging with T5s I chose 20/4, if I was using MH I would cut back to 18/6 (400w) or 16/8 (1000w) but that's just my opinion i.e. ( a belief or judgment that rests on grounds insufficient to produce complete certainty. 2. a personal view, attitude, or appraisal "-)...

when growing from seed it is absolutely necessary for dark period....from seedling the amount of dark time it receives helps determine the sex of cannabis.....check the link in my sig

as for clones that have been sexed 24 hour light or 18/6 and anything in between is the choice of grower for vegging....i have a strain that if it gets any darkness it will preflower so i just run 24/7.....but it is very easy w/LED's in veg...when i ran 600w MH i ran 18/6 so the room could cool down.

it is the light source that determines the amount of root growth.....when i grew under MH i could not keep my clones in peat pots for too long without the plant getting leggy and stretchy and not much root action shooting out of the peat pot having to transplant into larger pots.....now using all LED in the grow cycle i can keep clones in peat pots in a 1020 tray for as long as needed and the root mass is crazy compared to MH...nodes stack tighter also:smokin:

thats my .02 from my experience and observation of using different light sources and schedules in the grow phase :hippy:

in my many years i have never used 24/0. Just didnt seem right to me, but to each there own.:thumbsup:

First off, let me make this clear; I am not stating that any perticular photoperiod is "best".
The photoperiod you choose to run for vegative growth is truly a personal choice, based on your unique set of circumstances.

In my personal grow, I have a seperate mom/veg room that uses 18/6. Durring the 6 hrs the lights are out, the exhaust from that room goes to the flower room (during lights on) and increases the ambient co2 level.
When I transplant clones that were rooted in RW macro plugs into 4" RW delta blocks, I use 24/0 from LED. Mostly because the shelf I do that on is located in my work area, and cuttings are also rooted there. I can get roots growing into the delta blocks and veg the plants till they are 6-8" tall in 10-14 days, then into flower.

@Rusty, I would post a scientific paper dealing with "no harm to plants" if I could get files from my old computer. The paper I'm referring to was done by Dr. Raphael Mechoulam (the grandfather of cannabinoid research) who had to back up from that research and do some basic plant physiology to show his colleagues and critics that his use of 24 hr vegative growth for many of his studies had no effect on cannabis grown this way. BTW I think you'll find that the same chemical cocktail we look for to root cuttings is the same for creating roots of seedlings or even plants in veg to create roots.

@stra8outaWeed, I think we have had similar experiences with cold grow areas. You have hit the nail on the head...it is the quality of light used not the quantity. In fact I recently had a case (in a partnered grow) were there was too much light over some clonners and getting the cuttings to root became very difficult. Rather then run just one T5 actinic over the two clonners, my partner was trying to start cuttings using 4 T5s over the clonners....too much light.
OM

from seed, in soil, using 6500k HO T5's...I use 24/0 the first two weeks...then switch to 20/4

(I don't know what you can do with this information?...but, there it is.)...:jointsmile:

Hey, not trying to start a war, just to hear other sides and maybe pick up on a little of this or that. I think we are all very competent growers and do what we do because it works for us....in the long run that is what is important.

:thumbsup: :D

The majority of nutrient uptake and distribution happens during the dark period. This has been observed in almost every single terrestrial plant ever tested. It has been repeatedly tested in my food production sheds with monitoring probes checking the nutrient solution 24/7. The greatest amount of nutrient and water uptake happens during the dark period across every crop, from radishes to lettuces.

yup, plants are 24 hr factories. They are always doing something. :)

OM

I am not stating that anyone is wrong here. I will simply state what I have seen work. "They all work" is the simple answer here. The only difference is in the grower and the product. I have seen plants turn out great under many different light cycles. I have noticed though, a lot of plants will grow better under certain and different light cycles. I have also noticed the plants grown with a dark period will grow much sturdier and stronger. This is a debate that will go on forever. I suggest everyone just try out what works best for them. There are so many factors that can contribute to different light cycles but the grower must go through trial-n-error to figure out what works best in their situation.