Pros and Cons of 24/0 VS 18/6

[lilo]

imnotcrazy hey Yes that's interesting. I think cutting is in a sense a retarded plant, sick, requiring assistance - it is definitely not the best example of vegetative boom. It just got its roots amputated, sure they're some steps behind but the connection may not hold as strong with well balanced and happy plant.

cheers guys! take care

 

[joeylocz]

It was said that 18/6 would save money on electric. But I think it will cost more to turn the lights out/on. The start up takes alot of energy, where if let run constantly, will run smoothly without surge of energy for start up. I could be wrong, but I dont have as high bills since I switched to 24/0. Same with T.V., stereo, etc. I let them all run constantly and I dont pay more than $100 monthly on PG&E. (I live in a house)

 

[lilo]

Yes Joe you reminded me I must have saved some serious money on relays and timers in the past Sweet thoughts mate sweet thoights

 

[A.N.Other]

Cannabis is a C3 plant. Means it doesn't need a dark period.

18/6 will save you 25% electricity, and slow your growth down by 25%.

whilst technically speaking no darkness is required in a veg period in c3 plants (and c4 plants tbut less important, though CAM plants inherently REQUIRE a dark and light period) a dark period is (imho) beneficial and i would definately contest that 25% less light hours does not equate to 25% less energy or growth.

cannabis being a c3 photosynthesis plant means that like any other c3 plant photosynthesis must be balanced against an essentially competing reaction, photorespiration. my understanding of this balance is reasonably limited in term of science but if i remember right it goes a little something like this. rubisco, one of the key players in the photosynthesis side of the coin, is an inefficient little bugger. sometimes it will get on with it's expected job of producing organic (useable) carbohydrates in the ultimate form of starch (a polymer of glucose) from the carbon dioxide but at other times (due to co2 and o2 in competing availability) it will produce a different compound (phosphoglycolate) which whilst being useable about a quarter is lost as co2 and the other three quarters can be used by the plant but only after energy is expended to convert it to the correct form for the plant to use. certain conditions favour rubisco doing it's job right; high co2, moderate light intensities and moderate temperatures. similarly certain conditions will favour rubisco creating the less efficient form of carbon; low co2 levels, high temperatures and high light intensities.

whilst these factors are most important to making c3 plants often poor performers in arid conditions which goes to show that one factor does not a successful plant make as cannabis has plainly adapted around this limitation if it is all a c3, some could have a bearing on indoor cannabis growing.

covering each of those three factors seperately and contextually in terms of indoor cannabis growing i start to hit upon subjective reasoning and observation because there just isn't enough easily available hard research on cannabis so you'll have to excuse the next paragraph and icmag you are all entirely welcome to disagree.

first up let's ignore temperature as we can control that and keep it at proven preferable temperatures and THE AVERAGE grower does this. so that leaves us co2 and light intensity. tackling co2 first; standard air has between 0.03% and 0.06% (300-600ppm for the heads, hehe) of co2 so unless you are enriching from a genny or a tank you could argue (here's the subjectiveness) that the environment in THE AVERAGE grow contains low or at best moderate co2 levels. linked to this is lighting intensity, unless you are enriching with co2 there is a good chance that your plants are beyond their light saturation point beyond which co2 becomes the limiting factor in the balance. contextually then in this situation you could argue the average grow could has high relative light intensity.

if you did decide to argue all this then the conclusion that you may draw is that although both the light and the first stage of dark reactions (calvin cycle) work during daytime hours the first stage of the calvin cycle will work more efficiently at night (until the energy stored in the light dependant processes are depleted) in the average grow.

Anthropomorphism is a common thing and tends to get in the way of growing. Just because humans need sleep, doesn't mean cannabis does.

so, if rubisco was a bee and co2 was pollen........... hehhehe.

have a good weekend everyone.

 

[chosen]

If you are a person who just does a week or two of veg, go 24. If you are a long term grower trying for trees, go 18. The big difference is electricity bill and as mentioned in some cases the plants may kind of freak out. I like the energy savings. The big deal is more on the darkness period which has a greater effect in flowering. In veg the effects won't be as tangible...
Good luck..

 

[causal grower]

as chosen mentioned, it has a greater effect on the plant in the flowering and transition imo than in veg, disregarding $ for elec.

if you're one to care for giving your plants a slope to flowering, closer to nature if you care for that angle; and don't want to just shock them from like april lighting to august or something (wildly approx), then go 18/6 in the middle.

and if you're a canopy control freak, the measured doses of growth spurting may help with controlling/training height/uniformity.

 

[SkillsBot2935]

No one has bothered to point out that your cost per Kwh goes up the more power you use. At least in my area anyways... My rate starts at $0.11 Kwh and goes up to $0.34 Kwh. In my experience the extra time doesnt seem to contribute much to growth anyways and just isnt worth the increase in cost. Not to mention the extra wear on your ballast, bulb and ventilation equipment.

 

[Guest]

Ill throw a little different perspective out there....

I used to use 24-0....

it worked fine.....

At that time I was doing seed sogs......

Each batch was from seeds and they showed sex very fast.....

I tried 18-6 and found oddly they did now show sex as fast...

WHich is not what I expected....

I also found.... that clone mothers should not use 24-0 as it seems to cause the plant to eventually autoflower.....

So If you want to run 24-0 to show sex faster then flip to a cycle with some dark that seemed to work well.....

I have in the past had folks who agreed and very good growers....

but its just what Ive seen.....

 

[GorillaGrower]

what your saying makes sense to what is being described in this thread digeridoo

 

[GorillaGrower]

A.n. other.. i was trying to follow all that.. and did pretty well till the last paragraph ha

 

[Guest]

This thread has been done before, no reason for the debate, aside form the fact there is no real answer.


http://www.icmag.com/ic/showthread.php?t=29712&highlight=18/6

 

[Guest]

SO...........can we agree to disagree then?

Peace

 

[Ekras]

Not really - I like hearing about different peoples experiences between them. It helps broaden peoples understanding of the art.

 

[Guest]

My take is 24/0 produces the most heat while 18/6 gives the whole room 6 whole hours to cool when the lights are off. If you're running the air, you don't have to run it 24/7. Less energy use w/ 18 hour lights.

 

[Guest]

I agree with FiveSevenZero.

In the summer months I time the veg lights off 6 hours during the hot part of the day in my veg chamber. Saves alot of money with minimal impact.

In the winter months I go 24/0 in veg, when cooling the room for free is no problem.

 

[GorillaGrower]

good call The Tester same thing here.. there's many reasons for using each.

its not really a debate but more everyone chiming in on their pros and cons.. its funny but I didn't need to read more than a page of that last thread to notice that everyone either agreed with whats been said here in this thread about 18/6..and 24/0, both the good and bad of both.

 

[THC•20]

"Light period for cuttings

Plants have a free running internal bio-rhythm of 21-27 hours. In this rhythm, they need dark time. Cuttings have a built in daily rhythm (age also) that they inherit from their parent. Cuttings will root better with a 6 hours to 8 hourdark period because this is the main time when leaves and the stems transfer energy down to the root zone for storage and growth."

So does that mean if I had clones it'd be better to give them some darkness? Most people I've known to have clones gave them 24 hours of light without darkness, at least when they first took the cutting. Do you think giving them a light/dark period even from the moment I cut them would be better for root development?

 

[GorillaGrower]

clones should be done at 18/6 unless its in a aeroponic system and then it doesn't matter one bit. It can be done at 24/0 but you will not see as good results.

 

[A.N.Other]

A.n. other.. i was trying to follow all that.. and did pretty well till the last paragraph ha

ola gg, hehe, sorry man, i tend to get sloppy after ten minutes of typing. what i am essentially saying is that because of the high intensity lighting we use and the low co2 rates in the air the process which converts the energy collected by the leaves by the light energy into usable carbs for the plants to grow MAY work more efficiently at night in (1) the average grow room and (2) definately will if your temps get high and your humidity is low.

(2) is the easiest to justify so we'll do that first.

photosynthesis is broken down into two distinct set of processes which each contain many reactions. the first stages are called the light reactions because they are light DEPENDENT and the second stages the dark reactions because they are light INDEPENDENT which means they can operate in the light or in the absense of light. these dark reactions are often called the calvin cycle. the light reactions essentially take the light energy and convert into a ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate) for the dark reactions to consume, a by product of this light dependent side of photosynthesis is o2{*1}.

as i mentioned rubisco can consume o2 or co2 in order to create energy for the plant but if it consumes o2 rather than co2 the energy produced for the plant is produced at a lower rate of efficiency. in hot, dry conditions [relative] c3 plants close their stomata to conserve water which means that the oxygen by product of the light dependant reactions builds up in the plant tissue. as oxygen and carbon dioxide essentially compete to be used raising the level of oxygen will raise the chances of rubisco using oxygen rather than carbon dioxide, therefore producing energy less efficiently and therefore reducing potential growth rates. so the day is hot and dry and the stomata close but during the cooler, wetter night cycle air the stomata will reopen, oxygen can be released and carbon dioxide gets a better look in at the active site of rubisco increasing the efficiency of the calvin cycle in processing the energy stored during the light reactions.

(1) on the other hand is entirely hypothetical. there is a concept called the light saturation point which is the point at which the plant cannot use any more of the light energy available to it due to another limiting factor, this limiting factor is usually co2. given that we as growers love to throw light at our plants fairly generously there is a chance that in many grow room not enriched with added co2 this light saturation point may have been reached. this, contextually could mean that in many grow that two criteria for the increased chance of the less efficient use of oxygen by rubisco; high light intensity and low co2 rates. if this is the case, at night when light intensity is a non issue the dark reactions may also function more efficiently.

like i say all hypothetical science to back up anecdotal experience. whichever way i look at it, my garden likes to have some chillaxing time and a 4 - 6 hour night period benefits its overall plant health.




_______________________________________________
{*1} light is absorbed by pigments in the chloroplast and this energy is passed into either photosystem i or photosystem ii. if energy is passed to photosystem ii (ps2 hehe) it is used to split a water molecule into oxygen and hydrogen to free electrons to pass into photosystem i and from there to the calvin cycle.

 

[Guest]

A.N.Other
That was quite a statement. I have wondered about light saturation points and co2 depletion, etc.....

Bottom line is that this is just a weed, and most good strains will produce as expected if the gardener properly cares for the plant. Believe me, I have tried many different variations of growing over the years, but the best grows have always been 24/0 during veg with 1000 watt MH lights. I seem to get a more compact plant with more bud sites for the same amount of time, but thats just my experience with alot of the Indica I grow.