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Varying light frequencies with LEDs

mato

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Since I grow in an apartment, I have long wanted to find a way to expose my plants to varying frequencies of light throughout the day, instead of the typical pitch-black to blindingly-bright (and vice versa) photo period that comes with supplemental lighting. For this reason, I recently received a custom made, waterproof SMD 5050 red/blue 2:1 LED strip from a well known nursery in Germany, which I stripped and spliced to run on a standard 12vdc 60w laptop power supply. The idea is to allow the predominately red LED strips to come on two hours before the high output T5s and to turn off two hours later, with some overlap in between. Theoretically, this should allow the plants a chance to ease in and out of the various "cycles."




LEDs only:


LEDs on, T5s off.


LEDs on, T5s off.


LEDs on, T5s off.



with T5s


LEDs and T5s on.


LEDs and T5s on.



Will provide updates on plant performance in the future...



edit: Turns out the package was labelled incorrectly and these are SMD 5050.
 
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very cool!

i am skeptical that plants care very much about how quickly their photoperiod based day starts but could very well turn out to be a factor. regardless, the LEDs will surely help supplement spectrum-specific light to your rack

cheers
 
LED is the new light of the plant industry future. You all have to give it a try. and when your really start getting into fancy setups, you see extreme growth and reaction. I deal with this company and have seen extreme growth in both planted and marine aquaria. I grow mangroves at the shop with these lights.http://www.aquaillumination.com/
 
Long and short wave red lights are very important for plant biochemistry - many seasonal plants will not germinate unless the final/first light of the day is in the correct wavelength region.
 
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This setup is awesome! Can someone explain exactly why it's better to "ease" the plants into the light?
 
Great looking setup! I was also looking into supplementing with LEDs so I will be paying close attention to this thread. Kessil is the brand I'm looking into to get more of the red spectrum.
 
This setup is awesome! Can someone explain exactly why it's better to "ease" the plants into the light?


Drew, along with other environmental factors, there is evidence to suggest that plants need lower frequencies of light in conjunction with higher frequencies in order for proper stomatal movement to occur; this may seem obvious when you consider the varying frequencies of light at different times of the day (lower/redder in the morning and evening, higher/bluer in the afternoon, etc.). Although some people may think it's unnecessary (it probably won't induce huge, new growth with steroidal pitchers like we see from EP), the implications of proper stomatal functions are invaluable to the wellbeing of the plant; for example, the diffusion of CO2 from the air for carbon fixation, or the movement of water and nutrients from the roots to the shoots due, in large part, to transpiration. It's one of several reasons we say plants grown in "natural light" look healthier (if I could utilize the sun, I would). This experiment is just a way of making it seem more like a "day" to the plants, rather than a dank cell at Guantanamo Bay.
 
  • #10
Great looking setup! I was also looking into supplementing with LEDs so I will be paying close attention to this thread. Kessil is the brand I'm looking into to get more of the red spectrum.

Kessil's dense matrix LEDs are a great design. Unfortunately, they were quite a ways out of my price range.
 
  • #11
I was thinking something like dimming the lights so that in the morning the light output gradually increases and in the evening vice versa. But I'd have to switch to LEDs first. T8 tubes are not easy to dim.
 
  • #12
I have LEDs with a manual dimmer. I'm trying to figure out if I can make that work with a timer. It's a combo between a strip of 12K bright white: http://www.ecoxotic.com/panorama-pro-module.html and one of these: http://www.ecoxotic.com/stunner-led-strips.html I'm not sure if the second one really does any good for my plants all though I assume that counts for some red light. I was given these for free along with a 20 gallon reef tank from someone who didn't want it (sweet deal!) so I figured I'd utilize them for my plants since I'm not growing any crazy corals at the moment. Whats the difference between alternating red/blue like you have Mato, vs. the actinic blue that I have? It looks very similar to your photo of only the LEDs running. I know that my plants respond very well to the 12K bright white one but I'm not sure the "stunner strip" is even worth using. if it is I'd set it on a separate timer to achieve the effect your talking about.
 
  • #13
I have LEDs with a manual dimmer. I'm trying to figure out if I can make that work with a timer. It's a combo between a strip of 12K bright white: http://www.ecoxotic.com/panorama-pro-module.html and one of these: http://www.ecoxotic.com/stunner-led-strips.html I'm not sure if the second one really does any good for my plants all though I assume that counts for some red light. I was given these for free along with a 20 gallon reef tank from someone who didn't want it (sweet deal!) so I figured I'd utilize them for my plants since I'm not growing any crazy corals at the moment. Whats the difference between alternating red/blue like you have Mato, vs. the actinic blue that I have? It looks very similar to your photo of only the LEDs running. I know that my plants respond very well to the 12K bright white one but I'm not sure the "stunner strip" is even worth using. if it is I'd set it on a separate timer to achieve the effect your talking about.

I'm pretty sure there are products on the market that allow you to do this, but I never really investigated enough to find out. After a very brief search, it seems there may be some timer/dimmer combos used for the aquarium hobby. Not entirely sure if you can force your manual dimmer to work like that, but I'm sure someone much smarter than me could give you an answer.

The reason I went with the red/blue 2:1 was partly based on the results in nepaholic's thread, where he advocates the use of primarily red LEDs over both blue and white. However, a mix is never a bad idea. The frequencies of our lights will ultimately be a bit different and therefore stimulate different reactions from the plants, but it may be a negligible difference. Personally, I feel you do need some red in there, as I've seen the difference it makes firsthand when plants have been deprived of it (vining occurred almost immediately after the addition of lower frequency bulbs in some plants), whether you're talking about LEDs or fluorescents

I was thinking something like dimming the lights so that in the morning the light output gradually increases and in the evening vice versa. But I'd have to switch to LEDs first. T8 tubes are not easy to dim.

I thought about something similar, actually, but my lack of patience and desire to spend as little as possible led me down the tried and true path of household items. And since I forgot to say it in the original post, kudos to Av8tor for the suggestion that I use a laptop power supply, which made the process so much simpler than google would lead you to believe.
 
  • #14
silly google, DIY is for kids :p
 
  • #15
you can dim LED if the dimmer is programmed, most LED's need a program to run differetn applications. from my experiences you cannot just plug the LED's into a wall outlet that has a dimmer switch, they will flicker, strobe and potentially hum
 
  • #17
Was wondering how your plants were responding. Any noticeable change?
 
  • #18
LED is the new light of the plant industry future. You all have to give it a try. and when your really start getting into fancy setups, you see extreme growth and reaction. I deal with this company and have seen extreme growth in both planted and marine aquaria. I grow mangroves at the shop with these lights.http://www.aquaillumination.com/
AI is not a very good company. They use old leds that are overpriced. Although teh programming in the AI vega is pretty cool with lightning and stuff.
 
  • #19
I made an led lighting controller for dawn and dusk effects in aquariums using Arduino. Combined with my terrarium controller you could do everything for about $40.
 
  • #20
Just a quick update:

The plants have been responding very well to the LEDs. Albeit, I have realized that I must now be careful when positioning certain species in the brighter areas of the shelf, due to the intensity of the lights. Recently, I had two macrophylla turn slightly yellow due to the light intensity, and are now in a shadier spot where I will gradually acclimate them to the photo levels. When acclimated, however, Nepenthes appreciate more intense light than many of us realize, and will respond with vigor once adjustments have been made.

Almost immediately after adding the additional lights, four or five plants switched to internodal growth and colors became deeper and more noticeable. A few species of Sphagnum have expressed a motley array of colors, instead of the lime green I had become used to.

And although it's difficult to find the correlation when considering other factors, growth seems quicker for the plants as a whole. Since I lack the proper tools to measure stomatal conductance, attributing this to the introduction of lower light frequencies during the morning and evening hours would be presumptive; however, when considering even the most basic aspects of plant physiology, it would make sense to hypothesize positive changes in regards to plant health, rather than negative.
 
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