Photoperiod Question

Milan

Prolific Poster
Sep 28, 2005
34
0
6
62
Calgary, Alberta
I'm running my lights on a timer two times a day. 8-12 in the morning, and 6-12 in the evening. That's 10 hrs. Now, I'm wondering if there is a lag time when the lights come on, till the photosynthesis kicks in. If there is, they may not be effectively getting 10 hrs, and for how long should I increase it?
 

Simpte

Prolific Poster
Feb 17, 2005
76
0
6
Re: Photoperiod Question

I would imagine they are not getting 10 hrs of light. I base this off of the fact that plants don't pearl when your turn the lights on. It takes some time for them to get going.
 

matpat

Prolific Poster
Mar 29, 2005
74
0
6
57
Dayton, Ohio
Re: Photoperiod Question

If it were my tank I would cut out the 8-12am time period completely and instead run the lights a straight 2pm-12pm. Why are you staggering the lighting period? I would think it would be more beneficial to run the lights for a full 10 hrs, maybe 12 versus this staggered approach.
 

Safado

Junior Poster
Aug 28, 2005
10
0
1
Re: Photoperiod Question

I too stagger when my lights are on for my viewing pleasure.

Simpte said:
I would imagine they are not getting 10 hrs of light. I base this off of the fact that plants don't pearl when your turn the lights on. It takes some time for them to get going.

Does it? My understanding of pearling is the plants could very well be going like gangbusters, but until the water reaches O2 saturation pearling is not really noticeable. I haven't run accross any studies on the amount of time needed for a plant to start using it. An interesting study would be to put the lights on a half hour timer in an otherwise blacked out room. I imagine this could mess up your fish, but I wonder if the plants would grow as well as with 12 hours straight light.
 

Simpte

Prolific Poster
Feb 17, 2005
76
0
6
Re: Photoperiod Question

Most of my plants close up well before 12 hrs of light.
 

Safado

Junior Poster
Aug 28, 2005
10
0
1
Re: Photoperiod Question

In my short time in the hobby I have seen this question a few times. Have any of the more "tenured" among us heard of or done an experiment to determine the effects of the lengths of photo periods on plants?
 

matpat

Prolific Poster
Mar 29, 2005
74
0
6
57
Dayton, Ohio
Re: Photoperiod Question

Safado said:
In my short time in the hobby I have seen this question a few times. Have any of the more "tenured" among us heard of or done an experiment to determine the effects of the lengths of photo periods on plants?

I don't think I am one of the "tenured" ones in planted tanks nor have I done an "experiment" into the photoperiod plants prefer. However, simple observation will tell you when your plants "close up" for the night.

This happens to occur at about 10 hours in my tanks. Depending on light intensity this could happen sooner or later in your tank. You will notice in plants like Cabomba sp, Pogostemon sp, Limnophila sp, Rotala sp, etc. that the plants leaves will go from their horizontal postion to a more vertical position and seem to "close up" for the day. Whether they stop photosynthesizing at this time or merely slow down I can't say.
 

Milan

Prolific Poster
Sep 28, 2005
34
0
6
62
Calgary, Alberta
Re: Photoperiod Question

OK, some observations .... I've changed my photoperiod to straight 11hrs. What I noticed is that I get more pearling than before. It occurs mostly in the second half of the period, or perhaps after some 4 hrs, so definitely I was missing a big part of it in the staggered pattern. Also, some of the plants, like Cabomba "close up" earlier (after ~8-9hrs) while some, like Hygrophila P., keep going ... Mind you, I have only 2.2w/g, so that is probably a factor too ...
 

Tom Barr

Founder
Staff member
Administrator
Jan 23, 2005
18,699
786
113
Re: Photoperiod Question

With that amount of light, 10-11 hours full blast.

Regards,
Tom Barr
 

Tom Wood

Guru Class Expert
Jan 24, 2005
139
0
16
Kerrville/Austin, Texas
Re: Photoperiod Question

Milan said:
Staggering is a mere viewing convenience ...

One thing you might consider is adding some moonlights. On my 90 gallon I added four of the white 3-LED lights from here:

http://autolumination.com/fixtures.htm

I painted the inside of the hood white and pointed the LED lights at the sides so it's a reflected light. My tank is enclosed on three sides, so it was pretty dark before. Now I can see the tank when the main lights are off. At night, it's surprisingly bright. If your tank is smaller and/or open on the sides, then fewer LED lights will work.

TW
 

Milan

Prolific Poster
Sep 28, 2005
34
0
6
62
Calgary, Alberta
Re: Photoperiod Question

Tom Barr said:
With that amount of light, 10-11 hours full blast.

Regards,
Tom Barr
Yup! You are damn right ... I don't know if I can call 2.2w/g a "blast", but 11 hrs straight is the way to go.
 

Milan

Prolific Poster
Sep 28, 2005
34
0
6
62
Calgary, Alberta
Re: Photoperiod Question

Tom Wood said:
One thing you might consider is adding some moonlights. ...
I know SW people commonly use moonlights in their tanks. I would be interested to know if they have any side effects or benefits in FW applications. As far as "viewing" benefits go, I'm not sure they would satisfy my taste ... But hey, it's an option, and thanks for the info.