# How long to leave lights on for plants?



## flapjax3000 (Jul 4, 2009)

I just planted a new viv with java moss and peperomia prostrata. There are currently no frogs in it and I am awaiting the arrival of the rest of my plants. For now is it good for the plants to have long extended periods of light? Should I never turn the light off until I need a cycle for the frogs, or do I need to cycle the plants. I am assuming that consistent, longer light is better, but would like a more educated answer than my assumption.


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## ravengritz (Mar 2, 2009)

Plants need a break too. I'd give them at least 6 hours off/day.


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## Otis (Apr 16, 2006)

Plants need a resting period too, leaving the lights on for too long will stress them to death eventually. You should mimic the conditions the plants have in the wild, which is roughly 12 hours on. A 14 hour day would be fine, but so would a 10 hour day.


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## Frogtofall (Feb 16, 2006)

otis07 said:


> Plants need a resting period too, leaving the lights on for too long will stress them to death eventually. You should mimic the conditions the plants have in the wild, which is roughly 12 hours on. A 14 hour day would be fine, but so would a 10 hour day.


Ditto on this one. Very well put.

Also flapjax3000 is an awesome screen name!


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## flapjax3000 (Jul 4, 2009)

Thanks everyone, my plants are getting a well deserved rest. Frogtofall, we used to call our chubby roommate Flapjack in college. I thought it would make a great screen name.


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## james67 (Jun 28, 2008)

while many plants benefit from a day night cycle, i see no problem, particularly with the java and pep, with leaving lights on 18+ hrs per day.

james


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## james67 (Jun 28, 2008)

otis07 said:


> Plants need a resting period too, leaving the lights on for too long will stress them to death eventually. You should mimic the conditions the plants have in the wild, which is roughly 12 hours on. A 14 hour day would be fine, but so would a 10 hour day.


i failed to mention... in the wild the length of days changes throughout the year. a 12/ 12 cycle is therefore not the standard. in fact the change in light cycle is how many plants know when to do what.


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## Otis (Apr 16, 2006)

james67 said:


> while many plants benefit from a day night cycle, i see no problem, particularly with the java and pep, with leaving lights on 18+ hrs per day.
> 
> james


So you have experimented with various day/night cycles over an extended period of time? I have a hard time believing that these plants would grow optimully under conditions that were so different from those in the wild. Do you have anything to back this up?



james67 said:


> i failed to mention... in the wild the length of days changes throughout the year. a 12/ 12 cycle is therefore not the standard. in fact the change in light cycle is how many plants know when to do what.


But, considering that many dart frogs live fairly close to the equator and a lot of plants we use in our vivs are also tropical, I would say that 12/12 is the standard. Just because it's the standard, it does not mean it is universally accurate for all seasons. But I still maintain that a 12/12 cycle is going to be okay for dart frogs. I would feel more comfortable doing this than a 14/10 for example. 

And I see no benefit, if you had the lights on for 18 hours as you said, during the time before the frogs were introduced, if you plan to lessen the hours later on. Why not keep the conditions stable and allow the plants to acclimate to the conditions you plan to keep them in permanently? We already keep them in glass boxes so I think we should do as much as possible to keep the abiotic conditions as similiar to the wild as possible, and leaving the lights on for 18 hours is not natural


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## Frogtofall (Feb 16, 2006)

james67 said:


> i failed to mention... in the wild the length of days changes throughout the year. a 12/ 12 cycle is therefore not the standard. in fact the change in light cycle is how many plants know when to do what.


Yes for temperate and subtropical species. The equatorial (rain forest) stuff doesn't have much of a significant day/night change. These plants go by precipitation changes more so I think for blooming.


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## james67 (Jun 28, 2008)

otis07 said:


> So you have experimented with various day/night cycles over an extended period of time? I have a hard time believing that these plants would grow optimully under conditions that were so different from those in the wild. Do you have anything to back this up?
> 
> 
> 
> ...


many thing in the cultivation of plants in non "wild" conditions (in our homes and businesses) use fairly un-natural methods. in the case of plants un-natural isnt necessarily bad. take tissue cloning for example, or co2 supplementation. or crossbreeding for that matter.

and when frogs are introduced the lighting would certainly need to be adjusted. i use a 14/10 light/dark period and have never witnessed any problems with frogs or plants.

and when talking about keeping it stable, in the case of the java, it's entire environment is being changed. training an aquatic moss to grow terrestrially isnt entirely natural either. not to mention that there will be no frogs in his tanks for about a month and a half, and i seriously doubt that a change in lighting of 4 hours is going to negatively affect the growth of java moss or the pep. 

the use of high day to night periods are not uncommon in the commercial cultivation of many plants and i see no problems with this method. 

yes i have experimented with these two plants in particular in long light cycles and have witnessed no ill effect. the pep in the original poster's tank (flapjax300) is a clone from those exact plants.

james


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## flapjax3000 (Jul 4, 2009)

I have done a bit more research into my own question and found out quite a bit more information. Apparently the duration of light a plant should receive is dependent upon several factors which make it harder to figure out what is good for the plant. Initially you have to figure out how much light the plant is receiving. This consists of the the quality, duration, and intensity. The quality depends on type of light the plant receives ( natural light, artificial light, etc.). The duration is how long the plant is exposed light per cycle. The intensity is how much exposure there is to the plant. This consists of distance to light source, the amount of shade and types of bulbs used. These three factors are somewhat interchangeable. If a plant has good quality and intensity then it may not require a longer of duration. Any combination of the three seems to reach some sort of balance as long as one factor is not too extreme. 

The next group of factors depends on the age of the plant. From what I have read initial plant growth for seed is called propagation. During this stage plants benefit from durations of up to 24 hours per day. This creates a strong growth that causes the plant to be healthier and more resistant to disease. 

As the plants age then it more beneficial to reduce the duration of light because plants then need a period of respiration. During respiration plants use the sugars obtained through photosynthesis to build necessary proteins and hormones.

If you want your plants to reproduce and flower then it is more beneficial to move to a 12/12 cycle. The diurnal cycle triggers the plants to begin their reproductive stages.

So I guess there is no real answer to this question. It all depends on what you want you plants to do and what type of plant it is. My suggestion is if you are growing seedlings then more light is better. As they progress then reduce them to a more natural day cycle. If you want them to flower then a 12/12 seems standard. I wish I could have found a specific study to this question in an academic journal, but apparently this subject is very broad. So this is just my attempt at a simple overview of the journals that I read.


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## Otis (Apr 16, 2006)

james67 said:


> many thing in the cultivation of plants in non "wild" conditions (in our homes and businesses) use fairly un-natural methods. in the case of plants un-natural isnt necessarily bad. take tissue cloning for example, or co2 supplementation. or crossbreeding for that matter.


All of these things serve a purpose though, the C02 supplementation helps some plants grow better, the crossbreeding and tissue culturing is to create new plants. What purpose does the extended daylight period serve? if you can get the same results by having a 12/12 cycle whats the point of having a 18/6 one? it just wastes energy and gets the plants used to growing conditions they will not be living with permanently (this is assuming the plants don't die from stress).



james67 said:


> and when frogs are introduced the lighting would certainly need to be adjusted. i use a 14/10 light/dark period and have never witnessed any problems with frogs or plants.


This is a bit different than 18 hours as you said before, there's never 18 hours of light where these frogs live, 14 hours is a lot more reasonable.



james67 said:


> and when talking about keeping it stable, in the case of the java, it's entire environment is being changed. training an aquatic moss to grow terrestrially isnt entirely natural either. not to mention that there will be no frogs in his tanks for about a month and a half, and i seriously doubt that a change in lighting of 4 hours is going to negatively affect the growth of java moss or the pep.


I am not positive so I will not say for sure, but I don't see why there is any reason to believe that java does not grow terrestrially in the wild. 



james67 said:


> the use of high day to night periods are not uncommon in the commercial cultivation of many plants and i see no problems with this method.


Again, if you could link to something backing this up that would be great. 



james67 said:


> yes i have experimented with these two plants in particular in long light cycles and have witnessed no ill effect. the pep in the original poster's tank (flapjax300) is a clone from those exact plants.


Okay-no *ill* effects, but are there benefits? if not, I see no point in wasting energy keeping the lights on. 



flapjax3000 said:


> I have done a bit more research into my own question and found out quite a bit more information. Apparently the duration of light a plant should receive is dependent upon several factors which make it harder to figure out what is good for the plant. Initially you have to figure out how much light the plant is receiving. This consists of the the quality, duration, and intensity. The quality depends on type of light the plant receives ( natural light, artificial light, etc.). The duration is how long the plant is exposed light per cycle. The intensity is how much exposure there is to the plant. This consists of distance to light source, the amount of shade and types of bulbs used. These three factors are somewhat interchangeable. If a plant has good quality and intensity then it may not require a longer of duration. Any combination of the three seems to reach some sort of balance as long as one factor is not too extreme.
> 
> The next group of factors depends on the age of the plant. From what I have read initial plant growth for seed is called propagation. During this stage plants benefit from durations of up to 24 hours per day. This creates a strong growth that causes the plant to be healthier and more resistant to disease.
> 
> ...


Yep, you're right on with this. I'm not sure about the extended periods of light to trigger seeds to root as I don't normally grow from seeds, but it sounds possible. But as you are not growing from seeds I see no reason to have the extra light.


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## Frogtofall (Feb 16, 2006)

Flapjax3000, it sounds like the info you found is something you'd read on a Marijuana growing forum. These techniques are often used to make their plants grow certain ways to obtain better yields from what I understand.

We should just remember that replicating the environment of the creatures you're keeping is the best and safest way to take care of them. Dart frogs come from equatorial climates where the day/night cycles are generally closest to 12-14hrs of daylight and 12-10hrs of night. Coincidentally, our plants also come from this region so keeping it the same would be the most logical thing to do.


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## harrywitmore (Feb 9, 2004)

I would like to add just one thing. In a terrarium setting, you may actually not want optimal growth since you have a confined space. Otherwise you may just have a big ball of green. Now that may mean the plants are growing well but the look is not what you are going for. If you take some lessons from Bonsai then there may be good in stunting the growth of the plants in order to get the best affect. I would personally stay with 12/12 myself. I believe that if the lights are on too long then it would have ill affects on the animals which is the point of the enclosure in the first place.

Any study cited not dealing with a small enclosed environment would not give much indication on what would happen in a terrarium. The greenhouse is nothing like a small terrarium and neither is the rain forest.

Just my opinion.


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## flapjax3000 (Jul 4, 2009)

Some of the studies were about farmers obtaining maximum yields, but it was mainly for vegetables, not marijuana. I'm sure that marijuana would fall into the same category because it is a plant that people harvest, especially indoors. 

I agree that you do not want your aquarium overgrown, but if you only have a few cuttings and plan to fill out an area in your vivarium does it hurt if the plants get a head start? 

It all depends on the setup. Apparently if you have poor lighting, then longer durations are necessary for the plant to obtain its optimal photosynthesis. If lighting is better, then longer durations are not necessary. Also after about 17 hours of constant light plants will fade in color because they produce less chlorophyll and become scorched. 

Conditions may not be natural, but it does not mean it is not beneficial to the plant. For example, next time someone needs an ambulance to save their life I doubt they will be upset that it is unnatural. 

Unfortunately, these are some of the better pages I have read (Light For House Plants and Light, Temperature and Humidity). It is not a terrarium setting, dealing more with natural light, but it is closely related. I will try to find some better studies on this subject.

Anyway I did not mean to spark a long debate, was just curious of how I could have my plants booming before I put the frogs in the tank.


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## roxrgneiss (Sep 30, 2007)

I don't have much to say about photoperiod length, except that I have my timer set for a 14hr day/10hr night light cycle. 

If you are looking at this from a productivity standpoint, I think as much as light cycles, light intensity should be considered. If you want the most 'bang' for daily periods of lighting, try compact flourescents. You may already be using this sort of lighting, but I have a few general comments to add.

A Footcandles-calibrated, light intensity meter is a handy tool that allows you to figure out how much light is actually reaching the plants. I could say more about this, but it's purely conjecture. 

The intensity of lighting is as important as its duration, in my opinion, because this is how the plant feeds itself. Admittedly, I don't know a lot about the quantities of autotrophic nutrients that tropical terrarium plants need to produce per day to be considered 'well fed', but I tend to try to err on the side 'over feeding'. 

Byproducts of strong lighting, such as heat and dry air in the upper levels of terrariums can be challenging for some to overcome, but I think it's worth the effort. But kind of similar to a previous post, you may not want the plants to grow at optimal rates if they are fast/sprawling growers, if you aren't anticipating regular trimming of plants that do not remain compact. 

I hope that makes sense. 

Mike


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