Maximum Photoperiod Plants will Utilize - The Planted Tank Forum
 10Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 21 (permalink) Old 09-11-2020, 12:06 AM Thread Starter
Planted Member
 
PTrader: (0/0%)
Join Date: Feb 2019
Posts: 205
Maximum Photoperiod Plants will Utilize

Hi guys, just wanted to ask if plants have a maximum photoperiod where they stop utilizing the light after a certain period has passed. I don't want to increase the photoperiod/intensity if only algae will Utilize it.
I'm running a hightech setup with a light dimmer that ramps to 100 percent intensity for about 4 hours flanked by 3 hours worth of 70 percent flanked by 7 hours at 30 percent.

I'm not having an algae issues currently. I think the new filter is helping plus the higher plant load. Considering increasing the 100 percent to 6 hours.

Last edited by somewhatshocked; 09-11-2020 at 07:18 PM. Reason: please be mindful of where you post
Jah410 is offline  
Sponsored Links
Advertisement
 
post #2 of 21 (permalink) Old 09-11-2020, 07:13 AM
Planted Tank Guru
 
PTrader: (0/0%)
Join Date: Jun 2013
Location: WI
Posts: 12,020
Yes but your question is complicated and light isn't the major cause of algae.

First you need to understand if there are other limiting factors such as nutrients including CO2.

Then you need the info. plant profiles of which will hit the saturation point at what light output.

Also need to figure the DLI. Daily light integral.

http://w3.marietta.edu/~spilatrs/bio.../globexpl.html

Most aquatic plant light saturation points have afaict not been determined. Most "shade" plants still have saturation points well above what one normally sees in an aquarium.

Sadly the below chart doesn't give exact illumination levels.


https://1gt3sd9flvb3kwgha3wmyhbu-wpe...s-1024x706.jpg


Oops wrong graph.

https://cdn.shopify.com/s/files/1/02...g?v=1569911215
Quesenek likes this.

"A man with a watch knows what time it is. A man with two watches is never sure"
jeffkrol is offline  
post #3 of 21 (permalink) Old 09-11-2020, 01:07 PM
Planted Tank Guru
 
PTrader: (0/0%)
Join Date: Feb 2017
Location: PA
Posts: 2,040
I’ve often wondered the same thing and thought of it more as a question of “Is there a point where light intensity, e.g.; identifiable PAR/PUR values, and photoperiod combine to damage plants?” I don’t believe that I’ve reached such a point, with my setup, if one exists. So, I will describe what my plants are exposed to, regarding light.

First, CO2 is unlimited; I run it 24/7 and target an ~30ppm level. I also have never detected macro (includes Mg and Ca) limitations. We can’t effectively measure micro levels, so I can’t affirm my belief that they are not limited.

I have two photoperiods, separated by a 3-4 hour siesta. I say “3-4” because each photoperiod has a half-hour ramp to/from zero artificial light (ambient room light can allow plants to photosynthesize). I am not implying that a siesta is beneficial. I think it is, but haven’t proven, to myself, that it is.

The first photoperiod has about 40 PAR at the substrate (14” of water) for two hours (viewing purposes only), again surrounded by half-hour ramping. The second photoperiod has about 120 PAR at the substrate for seven hours (same ramping). PUR values are very high. I haven’t gone beyond these variables only because there is no point: no one is in the room enough to enjoy it, outside of those hours.

With the above settings, I have seen no detrimental effects with my plants. However, my plants are all stems, with the exception of some Dwarf Sag and DHG (mini). I have noticed that some stems (my Limnophila Aromatica, Pantanal and Wallichii) begin to close-up when the light begins to dim during the last photoperiod. This is something they learn to do. They also did it when my PAR values were much lower and when that second photoperiod was shorter, so it is triggered by a learned response to their end-of-the-day life, and is not photo exhaustion.

With these settings, I also have no algae. Some people would say that’s a lie, but I can’t see any in my tank (I had plenty in the past). I don’t attribute this entirely to plant health, although I think it is the majority of the reason. I believe that my snails do enough damage to the surface biofilm to do the rest of the algae inhibition.
Econde likes this.
Deanna is offline  
 
post #4 of 21 (permalink) Old 09-11-2020, 02:14 PM
Planted Tank Obsessed
 
Tiger15's Avatar
 
PTrader: (0/0%)
Join Date: Jan 2018
Posts: 440
I would say 10 hour is likely the maximum beneficial period plants can utilize, based on reports from Dutch growers that certain stem plants will close up beyond 10 hours. Non-stem plants may respond differently and we won’t know as they show no signal.

Lengthening the photo period is not a compensation for insufficient intensity. But shortening the period is fine with sufficient intensity to control algae. Some aquascapers reported that they can achieve lush growth free of algae for just 6 hours a day.

Low light plants can suffer from too high light intensity. I’ve seen YouTube tour of aquatic plant nursery green house in which low light plants are covered with sun screen. I don’t know if low light plants in high light aquarium will suffer as artificial light is no where near sunlight intensity.

I schedule split photo periods for my viewing, 4 hour in the morning, and 4 hour in the evening with 7 hour siesta period in between. I don’t know if a siesta period is beneficial or not to my plants as I have CO2 and no algae.
Econde likes this.
Tiger15 is offline  
post #5 of 21 (permalink) Old 09-11-2020, 06:04 PM Thread Starter
Planted Member
 
PTrader: (0/0%)
Join Date: Feb 2019
Posts: 205
Quote:
Originally Posted by Deanna View Post
I’ve often wondered the same thing and thought of it more as a question of “Is there a point where light intensity, e.g.; identifiable PAR/PUR values, and photoperiod combine to damage plants?” I don’t believe that I’ve reached such a point, with my setup, if one exists. So, I will describe what my plants are exposed to, regarding light.

First, CO2 is unlimited; I run it 24/7 and target an ~30ppm level. I also have never detected macro (includes Mg and Ca) limitations. We can’t effectively measure micro levels, so I can’t affirm my belief that they are not limited.

I have two photoperiods, separated by a 3-4 hour siesta. I say “3-4” because each photoperiod has a half-hour ramp to/from zero artificial light (ambient room light can allow plants to photosynthesize). I am not implying that a siesta is beneficial. I think it is, but haven’t proven, to myself, that it is.

The first photoperiod has about 40 PAR at the substrate (14” of water) for two hours (viewing purposes only), again surrounded by half-hour ramping. The second photoperiod has about 120 PAR at the substrate for seven hours (same ramping). PUR values are very high. I haven’t gone beyond these variables only because there is no point: no one is in the room enough to enjoy it, outside of those hours.

With the above settings, I have seen no detrimental effects with my plants. However, my plants are all stems, with the exception of some Dwarf Sag and DHG (mini). I have noticed that some stems (my Limnophila Aromatica, Pantanal and Wallichii) begin to close-up when the light begins to dim during the last photoperiod. This is something they learn to do. They also did it when my PAR values were much lower and when that second photoperiod was shorter, so it is triggered by a learned response to their end-of-the-day life, and is not photo exhaustion.

With these settings, I also have no algae. Some people would say that’s a lie, but I can’t see any in my tank (I had plenty in the past). I don’t attribute this entirely to plant health, although I think it is the majority of the reason. I believe that my snails do enough damage to the surface biofilm to do the rest of the algae inhibition.
I've also noticed that same learned behavior from some of the same plants. Also rotala rotundifolia. In the past, if I change the photoperiod, it would take them about 3 days to relearn the new light cycle. Quite interesting I thought.

I am kind of following a similar approach to you. I basically EI dose and keep co2 high. I've also got a lot of cleanup crew to hopefully keep algae down from here on.

I may try lengthening my max intensity slowly based on what you've said.
Econde likes this.
Jah410 is offline  
post #6 of 21 (permalink) Old 09-11-2020, 06:07 PM Thread Starter
Planted Member
 
PTrader: (0/0%)
Join Date: Feb 2019
Posts: 205
Quote:
Originally Posted by Tiger15 View Post
I would say 10 hour is likely the maximum beneficial period plants can utilize, based on reports from Dutch growers that certain stem plants will close up beyond 10 hours. Non-stem plants may respond differently and we won’t know as they show no signal.

Lengthening the photo period is not a compensation for insufficient intensity. But shortening the period is fine with sufficient intensity to control algae. Some aquascapers reported that they can achieve lush growth free of algae for just 6 hours a day.

Low light plants can suffer from too high light intensity. I’ve seen YouTube tour of aquatic plant nursery green house in which low light plants are covered with sun screen. I don’t know if low light plants in high light aquarium will suffer as artificial light is no where near sunlight intensity.

I schedule split photo periods for my viewing, 4 hour in the morning, and 4 hour in the evening with 7 hour siesta period in between. I don’t know if a siesta period is beneficial or not to my plants as I have CO2 and no algae.
I'm curious about the 10 hour max. Wonder if that's just learned behavior, or if it's actually the limit.

Also I've have wendelov Java fern in the past under the same light but for 10 hours (didn't know how strong my light actually was). It actually fried the plant. Tried twice and both times the leaves actually crisped. Didn't melt!
Jah410 is offline  
post #7 of 21 (permalink) Old 09-11-2020, 06:32 PM
Algae Grower
 
Baysha's Avatar
 
PTrader: (0/0%)
Join Date: Apr 2020
Location: Czech Republic
Posts: 15
My low tech tanks are on about 15 - 16 hours of light a day (I haven't gotten to programming the timers yet, I switch the lights on and off manually so it's not always at exactly the same time). Plants are doing great, red plants are red, no algae. Interesting that both of you mention stem plants closing up, I have never seen this behavior.

Diana Walstad recommends a photoperiod longer than 12 hours with the explanation that shorter photoperiod might slow down the growth of some plants because it basically means "winter is here". But I think it's not the whole story - most high-tech people use shorter photoperiods and their plants are growing like crazy. So maybe it's a combination of other environmental factors? High-tech versus low-tech? I don't know. Would be interesting to find out! Anyway, long photoperiod works for my tanks and I love that I can admire them from early morning to late evening.
Baysha is offline  
post #8 of 21 (permalink) Old 09-11-2020, 06:58 PM
Planted Tank Enthusiast
 
PTrader: (1/100%)
Join Date: Sep 2008
Location: Palm Bay
Posts: 602
To throw a wrench in the 10 hour thing.

I have a low tech tank that I run a NICREW ClassicLED Plus at about 40% on. The photoperiod is around 15 hours and the plants don't fold up like they do in my high tech tank.

My high tech tank even running 30 4000k Luxeon LED's over my 55 gallon at 100% for 10 hours a day for a month, the plants didn't fold up until after the lights were off.
There was no difference from running everything at normal levels. Same was true for Sunplus CW, but I didn't try the 100% thing for as long as the 4000k LED's.

It wasn't until I installed some Cyan/DR/Violets into my DIY setup that my plants said they had enough at around 11 hours photoperiod that they started folding before the lights were off.

Whether the plants were utilizing the light, I have no idea, but they were still pearling and they were still open.

As jeffkrol said, the main issue with high intensity lighting is Co2 levels and stability. When Co2 is the limiting factor coupled with high intensity lighting, it causes an unstable system and unstable Co2 = Algae.
Quesenek is offline  
post #9 of 21 (permalink) Old 09-11-2020, 07:36 PM
Planted Tank Guru
 
PTrader: (0/0%)
Join Date: Feb 2017
Location: PA
Posts: 2,040
Quote:
Originally Posted by Baysha View Post
Diana Walstad recommends a photoperiod longer than 12 hours with the explanation that shorter photoperiod might slow down the growth of some plants because it basically means "winter is here". But I think it's not the whole story - most high-tech people use shorter photoperiods and their plants are growing like crazy. So maybe it's a combination of other environmental factors? High-tech versus low-tech? I don't know. Would be interesting to find out!
It's all about the light. The high light levels used in high-tech tanks drive growth much more strongly than in low-tech. However, we have to add CO2 and higher levels of other nutrients, to keep up with that growth, or the plants will burn themselves out, in a manner of speaking. The dying/struggling plants, then, would bring on algae.

Additionally, in high-tech tanks, there is much less forgiveness for inconsistencies in supplying the plants what they need. We can supply high light for 12 hours or more, but it needs to be consistent or imbalances start to have a negative effect on plants. The same goes for CO2 consistency and somewhat with the other nutrients. Low-tech tanks are much more forgiving in this regard and, therefore, easier to maintain.
Econde likes this.
Deanna is offline  
post #10 of 21 (permalink) Old 09-11-2020, 09:01 PM
Planted Tank Obsessed
 
Tiger15's Avatar
 
PTrader: (0/0%)
Join Date: Jan 2018
Posts: 440
Not all stem plants but the fine foliage type such as Ambulia, Cabomba or Hygro polysperma react to opening and closing. The reporting of 10 hour maximum photo period are from Dutch gardeners with high light CO2 setups. The response from low to medium tech setups is likely different due to influence of multiple variables. I have no idea how non stem plants react as there is no readable signal I’m aware of.
Tiger15 is offline  
post #11 of 21 (permalink) Old 09-11-2020, 09:12 PM
Planted Tank Guru
 
PTrader: (0/0%)
Join Date: Jun 2013
Location: WI
Posts: 12,020
Quote:
Originally Posted by Deanna View Post
It's all about the light. The high light levels used in high-tech tanks drive growth much more strongly than in low-tech. However, we have to add CO2 and higher levels of other nutrients, to keep up with that growth, or the plants will burn themselves out, in a manner of speaking. The dying/struggling plants, then, would bring on algae.

Total agreement w/ dying/senescent plant material will cause algae issues. spores need ammonia to germinate and cannot use any other Nitrogen sources I'm aware of.


As to "burning out"... well light on the surface of a lake and open stream can push 2000 PAR at the surface..Good lights might push 500 PAR at the tank surface or w/ marine ones 1000PAR.


Emergent forms of aquatics will see full daylight (granted it's not constant over the day cycle) but don't usually burn themselves out (exposing shade acclimated ones will of course) but CO2(atm) is really a lot higher than your 30...like currently 400ppm-ish.


SADLY the below pdf doesn't list algae tolerance to high CO2 levels..
http://osse.ssec.wisc.edu/curriculum...on_Dioxide.pdf


As far as I "know" some streams can have higher CO2 levels than a lake but I suppose the oxygenation factor comes into play.


Obviously ind. species and their "predispositions" matter.


As to another point brought up above.. studies show some plants can do fine or even better w/ a 24hr light cycle. Of course these studies were done on terrestrials where CO2 is never limiting..

Guess one can think of duckweed which sort of shares the best of both worlds and how crazy prolific it is at high PAR levels..
Quesenek and Deanna like this.

"A man with a watch knows what time it is. A man with two watches is never sure"
jeffkrol is offline  
post #12 of 21 (permalink) Old 09-11-2020, 09:42 PM
Planted Tank Guru
 
PTrader: (0/0%)
Join Date: Feb 2017
Location: PA
Posts: 2,040
Quote:
Originally Posted by jeffkrol View Post
As to "burning out"... well light on the surface of a lake and open stream can push 2000 PAR at the surface..Good lights might push 500 PAR at the tank surface or w/ marine ones 1000PAR.


Emergent forms of aquatics will see full daylight (granted it's not constant over the day cycle) but don't usually burn themselves out (exposing shade acclimated ones will of course) but CO2(atm) is really a lot higher than your 30...like currently 400ppm-ish.
Yup: I was afraid that using that “burn themselves out” phrase might be too violent. Although you clearly see the meaning, others might not realize that the intent was to imply that high light can cause a plant to exceed the supply of nutrients necessary to maintain its’ health.
Quesenek likes this.
Deanna is offline  
post #13 of 21 (permalink) Old 09-12-2020, 12:42 AM
Planted Tank Obsessed
 
Tiger15's Avatar
 
PTrader: (0/0%)
Join Date: Jan 2018
Posts: 440
Getting burnt means that the plant is damaged by high light. I know immersed grown Java fern and Anubias in green house need sun screen protection, and shade loving terrestrial plants like Hostas can get burnt under full sun.

But submerged grown plants have water protection so it is not the same. According to Jeffcroll chart, when light reaches the saturation point of a plant, growth will plateau out, not implying burnt out.

https://1gt3sd9flvb3kwgha3wmyhbu-wpe...s-1024x706.jpg

Has anyone experienced low light plants get burnt out by high light under water?
Tiger15 is offline  
post #14 of 21 (permalink) Old 09-12-2020, 02:10 AM Thread Starter
Planted Member
 
PTrader: (0/0%)
Join Date: Feb 2019
Posts: 205
Quote:
Originally Posted by Jah410 View Post
Quote:
Originally Posted by Tiger15 View Post
I would say 10 hour is likely the maximum beneficial period plants can utilize, based on reports from Dutch growers that certain stem plants will close up beyond 10 hours. Non-stem plants may respond differently and we won’t know as they show no signal.

Lengthening the photo period is not a compensation for insufficient intensity. But shortening the period is fine with sufficient intensity to control algae. Some aquascapers reported that they can achieve lush growth free of algae for just 6 hours a day.

Low light plants can suffer from too high light intensity. I’ve seen YouTube tour of aquatic plant nursery green house in which low light plants are covered with sun screen. I don’t know if low light plants in high light aquarium will suffer as artificial light is no where near sunlight intensity.

I schedule split photo periods for my viewing, 4 hour in the morning, and 4 hour in the evening with 7 hour siesta period in between. I don’t know if a siesta period is beneficial or not to my plants as I have CO2 and no algae.
I'm curious about the 10 hour max. Wonder if that's just learned behavior, or if it's actually the limit.

Also I've have wendelov Java fern in the past under the same light but for 10 hours (didn't know how strong my light actually was). It actually fried the plant. Tried twice and both times the leaves actually crisped. Didn't melt!
I mentioned this earlier.
Jah410 is offline  
post #15 of 21 (permalink) Old 09-12-2020, 02:53 AM
Planted Tank Enthusiast
 
PTrader: (1/100%)
Join Date: Sep 2008
Location: Palm Bay
Posts: 602
Quote:
Originally Posted by Tiger15 View Post
Getting burnt means that the plant is damaged by high light. I know immersed grown Java fern and Anubias in green house need sun screen protection, and shade loving terrestrial plants like Hostas can get burnt under full sun.

But submerged grown plants have water protection so it is not the same. According to Jeffcroll chart, when light reaches the saturation point of a plant, growth will plateau out, not implying burnt out.

https://1gt3sd9flvb3kwgha3wmyhbu-wpe...s-1024x706.jpg

Has anyone experienced low light plants get burnt out by high light under water?
From some googling on java fern it seems like if given the needed levels of nutrients and Co2 it doesn't care about the light levels that we typically provide for aquariums, and it will grow relative to the amount of light and nutrients its receiving.

I think there might have been a misunderstanding on the term low-light plants, what I've been able to find is that this only really means that the plants can grow in low light levels, not that they're specifically low light plants in our aquariums relative to what they would receive in nature.
The main issue that we run into with placing slow growers (low light plants) under high light is that the leaves might find themselves covered in algae from the light accumulation, just like substrate or hardscape.
Quesenek is offline  
Reply

Tags
None

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome