Is there optimal amount of light that you can give for photoperiod plants? 18/6 to 24 hours? And when to swap?

twentyeight.threefive

Well-Known Member
The plant will not grow under 24/7. Or rather it will grow for a while, but then it will start to have problems. There are a few special varieties, which can be grown under 24/7 lighting. I haven't tried growing them 24/7. It's just what I read, but the info should be accurate.
So you haven’t actually tried to grow them it’s just what you read somewhere? Did the place you read this state the amount of light they were receiving over 24/0 lighting?
 

jimihendrix1

Well-Known Member
Ive been using 24/0 since the dawn of HID in the 70s. I used Halide for the first 20 years, until Hortilux started enhancing the HPS with some Blue. I went to 1000w Hortilux HPS in the 90s.

I also start seeds/seedlings under 1000w Hortilux HPS or 1150w Gavita DE HID, or a Gavita 1700e/LED. I blast them from day one. If we were in the mountains of the Andes, seedlings would be getting blasted from day one with huge amounts of light, and UVA/B. So I see no downside in blasting seedlings/rooted clones from the start. IMHO it makes them grow really fast, and develops strong side branching early on.

I grow big plants in large containers due to being in an unfriendly state to keep total numbers of plants down somewhat.

I start seeds/clones in 32oz Uline Deli Containers with Promix BX, and when theyre ready to transplant I veg them in 5 gallon grow bags for 45-70 days. When theyre ready to be transplanted the root system takes up all of the room in a 5 gallon container, usually, but is strain dependent. Fast growing Sativa dominant varieties usually fill out the space the fastest. Then when theyre ready to flower, and using an old Barneys Farm G13 x Haze that Ive had the mother plant for 12 years, I put the grow bags in 20 gallon containers and cut the bags off of the plants when ready to flower, and may veg them a week more in the 2o gallon containers, and when theyre done 70 days later, the root system takes up 100% of the space in 20 gallons of Promix BX. Ive not seen any short, or long term root growth problems vegging on a 24/0 schedule. I can lift the whole 20 gallons of soil out of the container using the stalk of the plant, and its completely root bound when theyre done.

I do have very very good ventilation/ Fresh air exchange, and temps really never exceed 85f. If you dont have good fresh air exchange the plants will not grow optimally. All in all if you have strong light, good air exchange, plenty of good soil, proper PH, and adequate amounts of food, and water, not much will hold them back. If even 1 aspect of the grow isnt optimal, progress will be slowed, or completely fucked.

Once every 7- 10 days I do turn the lights off for 4 hours to cool down the ballasts, but have also used 24/7 for 60 days veg, and never turned the lights off, and didnt have any negative impact on the plants.
I can get 22oz-24oz per 1 plant/G13 x Haze with 60 days veg. The G13 x Haze also sstretches 4-5 times its size when flipped, and I look for strains that stretch alot after flip. Im not takling about stretching where the buds are not thick either. Long, thick, dense colas. I also bend my plants over early on, and grow them like a forsythia bush. I also dont top.
 

ComfortCreator

Well-Known Member
Again wrong on so many points. You don’t even understand the definition of DLI. It has nothing to do with indoors/outdoors.

“If 24/0 was superior, every indoor grow op would use it, and none of them do.”

More flawed logic. You will have quicker and more growth with max DLI. It’s not used by a lot of commercial growers because it’s not cost effective.

Not sure where calling me rude came in from, but I’m quite able to process simple comments, even the incorrect ones.
DLI comes from the Sun, fool.
The sun doesnt light any plants 24/0.
Neither does any grow op.

Nothing I said was wrong. I didnt mention max DLI. You have arguments with yourself weirdo!
 

ComfortCreator

Well-Known Member
The whole discussion is pointless as mentioned already. Yes it technically doesnt need a dark period but how many people run 24/0 through veg? A few. And all of us who have done it tend to remark it doesn't seem to offer much benefit...a little faster and a higher electric bill.

DLI..yes everybody knows also there are studies attempting to quantify max light they can absorb depending upon conditions and CO2 levels.

Little of this really addresses what is ideal necessarily. Most grow ops are looking to insure they hit a minimum DLI vs worrying if they can actually shoot for the max.

There is no perfect guide for newbies or somewhat experienced growers because as Star Dog said...someone who is not well versed in all this cant really understand all the dynamics and how they relate.

Even some of the more famous and well known growers do things they like that are not necessarily proven as best practices.

Heck look at harvest and drying....like this forum or anywhere else there are 100 ways it is done.

For all the long discussions of exactly how to dry and cure so many cultivators dry it for a few days and send it off. Is that a best practice? Of course it depends upon your measuring stick.
 

lusidghost

Well-Known Member
The whole discussion is pointless as mentioned already. Yes it technically doesnt need a dark period but how many people run 24/0 through veg? A few. And all of us who have done it tend to remark it doesn't seem to offer much benefit...a little faster and a higher electric bill.

DLI..yes everybody knows also there are studies attempting to quantify max light they can absorb depending upon conditions and CO2 levels.

Little of this really addresses what is ideal necessarily. Most grow ops are looking to insure they hit a minimum DLI vs worrying if they can actually shoot for the max.

There is no perfect guide for newbies or somewhat experienced growers because as Star Dog said...someone who is not well versed in all this cant really understand all the dynamics and how they relate.

Even some of the more famous and well known growers do things they like that are not necessarily proven as best practices.

Heck look at harvest and drying....like this forum or anywhere else there are 100 ways it is done.

For all the long discussions of exactly how to dry and cure so many cultivators dry it for a few days and send it off. Is that a best practice? Of course it depends upon your measuring stick.
I've been running 24/0 since I started growing. It's a very common practice.
 

ComfortCreator

Well-Known Member
which is it? you just said the exact opposite a few posts ago.

and cervantes talks about 24/0 in his book so way more than a "few" run it.
I dont think I said it needs a dark period. I do think almost everybody uses one.

My comment is simply that nature tells us how to grow. You can do it different and that works but imo nature has told us what to do. There is no proof it is "better", I believe there is proof it can be faster.
 

rkymtnman

Well-Known Member
I dont think I said it needs a dark period. I do think almost everybody uses one.

My comment is simply that nature tells us how to grow. You can do it different and that works but imo nature has told us what to do. There is no proof it is "better", I believe there is proof it can be faster.
ok, well here's a what if for you:

what if you run 18/6 and your room gets too cold by hour 4 of dark. would you rather run a heater or just run your lights 24/0 instead?

for some people, 24/0 is the best option.
 

lusidghost

Well-Known Member
The "natural" argument is funny to me. I'm growing in a rockwool slabs using powdered nutrients under LED lights in a tent. If my plants get pests I kill them with chemicals. I have an AC running right now. I check the PH and the EC with electronic devices. The plants have also been intensively bred for decades from plants that were bred for centuries. It's more alien technology than earth property at this point.
 

ComfortCreator

Well-Known Member
ok, well here's a what if for you:

what if you run 18/6 and your room gets too cold by hour 4 of dark. would you rather run a heater or just run your lights 24/0 instead?

for some people, 24/0 is the best option.
I have done both (24/0 and 18/6 or 20/4 with a heater. Both can work. The first few weeks I run 24/0. I get it. I have no criticism of running 24/0. Heck is the oil heater more expensive than the lights? Lots of variables!

I think it is easier to run with a dark period, and the vast majority of guides and pros suggest we use one. A simple google search will come up with 9 out of 10 saying run a dark period. I see this as following nature, it simply allows for some variance in conditions.

Question for you -- if you dont have a temp issue, is running 24/0 "better?" It requires that we have a common choice for how to measure...is speed, yield, quality the key? That is why imo how we grow is mostly personal. I'm not sure there is an "ideal" which the OP asked about.

I
 
I just shut off my veg lights from noon til 6pm just to keep the heat down and the utility requires me to reduce my energy from 2 til 6 or I get charged an astronomical(up to 25 to 50 cents a KWH) amount of money. This is what they start doing in order to combat the Marijuana Law that the people of Michigan passed. They will force you to grow indoors and consumers energy will start sending you paperwork in the mail about consuming an enormous amount of energy, start up charging you for additional KiloWatt hours. My emporia energy monitor and the KWH meters on my grow panel says I should only be consuming around 130 to 150 dollars in electricity per grow. The energy company on the other hand charged me around 400 and the two different readings I am getting from Emporia, cheap energy monitors clamped around the main service wires coming into the electrical panel is so far off, I find it fraudulent but this is for another discussion.
 

lusidghost

Well-Known Member
I think it is easier to run with a dark period, and the vast majority of guides and pros suggest we use one. A simple google search will come up with 9 out of 10 saying run a dark period. I see this as following nature, it simply allows for some variance in conditions.
Where is nature is there a 18/6 light schedule? Especially for 4 to 8 weeks at a time? "Google search" and "pros" is pretty funny. Who are these pros?
 

ComfortCreator

Well-Known Member
Lmao, ok.

You might want to look up the definition before you make yourself look even dumber.
From wiki: "...Scientists have tried to solve this by reporting light intensity measured for one or more sunny days at noon, but this is grasping the light level for only a very short period of the day. Daily light integral includes both the diurnal variation and day length, and can also be reported as a mean value per month or over an entire experiment."

Notice the use of "sunny" and diurnal variation...DAY length.

"...Abstract

The National Renewable Energy Laboratory developed the >>>National Solar Radiation Database<<< to provide accessible solar radiation data to the research community for various uses. Previously, we created a series of monthly daily light integral (DLI) maps to provide a tool for horticulturists to estimate the potential growth and flowering responses for various plants throughout the year.>>> The original DLI maps were based on solar radiation data from 239 sites recorded from 1961 to 1990.<<<<< The DLI maps presented in this article were created from an updated database that included data from 1998 to 2009..."

You spend your time trying to police this sxxx and you are found to keep arguing that light intervals have nothing to do with the sun? All their experiments looked at plants growing outdoors. Yes my little genius, you can use DLI inside because they have studied it enough to provide some guidance. But for your crazy brain to think this concept is divorced from the Sun says you have never really grown anything outdoors before.

How stupid are you bro?
 
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ComfortCreator

Well-Known Member
Where is nature is there a 18/6 light schedule? Especially for 4 to 8 weeks at a time? "Google search" and "pros" is pretty funny. Who are these pros?
Nature varies its amount of daily sunlight. Thats how we figured out when they flower.
18/6 is not known as "perfect". Having a dark period is recommended in almost every guide. You doing 24/0 and Cervantes mentioning it does not prove your point.

Why is it so threatening to have 24/0 be challenged? Of course you can run 24/0. Do most people use it? No. That's it.

I dont remember ever claiming anything controversial. Am I wrong saying the vast majority run with a dark period? Is it because they never tried or thought of 24/0? I ran it, worked fine.
 

lusidghost

Well-Known Member
Nature varies its amount of daily sunlight. Thats how we figured out when they flower.
18/6 is not known as "perfect". Having a dark period is recommended in almost every guide. You doing 24/0 and Cervantes mentioning it does not prove your point.

Why is it so threatening to have 24/0 be challenged? Of course you can run 24/0. Do most people use it? No. That's it.

I dont remember ever claiming anything controversial. Am I wrong saying the vast majority run with a dark period? Is it because they never tried or thought of 24/0? I ran it, worked fine.
You're the one talking about pros and nature and whatnot. I would guess at least half of this forum runs 24/0. Maybe more, maybe less. Regardless, it's a large number of growers. Respectable ones at that.

My point is if there is any difference in outcome, it's so minute that it's not worth worrying about. If it's easier to run them 24/0, do that. If you prefer 18/6, do that. This is really the most trivial argument you can have pertaining to growing cannabis.
 
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