LED Gardening - diyAudio
Go Back   Home > Forums > Member Areas > The Lounge

The Lounge A place to talk about almost anything but politics and religion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 3rd June 2014, 11:23 PM   #1
wicked1 is offline wicked1  United States
diyAudio Member
 
wicked1's Avatar
 
Join Date: Jan 2008
Location: Midwest
Default LED Gardening

We were talking about LED's in tube cathodes, and then high powered LED's and grow lights were mentioned.

I've been playing w/ high powered LED's for aquarium lighting for several years, and last fall built some grow lights out of spare LED's.

I used bridgelux emitters. They were left over from the aquarium project, so I had various shades of white. They're high powered emitters. I've got ~50 watt and ~20 watt emitters. I liked the point source of light for my aquarium, rather than having smaller emitters spread out over the canopy, so that's why I used those. A bunch of smaller emitters is definitely more efficient than having all 50 watts packed into a small area.

I've found for terrestrial plants, the emitters w/ the most red in the spectrum work best. Generally low kelvin numbers. They're less efficient than the cool emitters, but plants have done much better under them.

I used about 315 watts of HPS and MH in previous years to overwinter a bunch of peppers and a lime tree. Last year I used 90 watts of LED, and the plants did just as well.

I generally use a 50 watt compact fluorescent fixture (long tube, not the coils for home lighting) over each seedling tray in the early spring. This year I used a 20 watt LED over one tray. The LED tray looked like the plants were in the sun, compared the the thin lanky plants under the fluorescent.

The bridgelux emitters I've got want about 19v at 1A, and that's perfect for an old laptop power brick (Which I get for free). I use a CCS after the laptop power supply.
  Reply With Quote
Old 4th June 2014, 02:49 AM   #2
diyAudio Member
 
Join Date: Nov 2005
Location: NorCal
What would you use for growing live freshwater aquarium plants? I've been out of the aquarium hobby for some years, but the planted tanks I have had were my favorites.

Bill
__________________
The difference between theory and practice is that in theory there is no difference between theory and practice, but in practice there is.
  Reply With Quote
Old 4th June 2014, 01:46 PM   #3
wicked1 is offline wicked1  United States
diyAudio Member
 
wicked1's Avatar
 
Join Date: Jan 2008
Location: Midwest
I've got a small reef, and over that I have a big 50w warm white emitter , surrounded by a bunch of smaller 3w blue and royal blue. I'm trying to find someone to take my little reef tank, as I don't really have the time for it anymore.

I've got a big 220 gallon freshwater planted tank.. Co2 injection. Soil substrate, w/ a gravel 'lid' over the dirt. I love it! Fish are super happy in it. The freshwater plants like the warm white light. (they're basically the same as terrestrial plants). I've got a few of the 20 watt warm white emitters, and still a 10,000k MH 150watt bulb. Eventually the MH will get replaced w/ another ~20 watt white emitter, and a few blue and red emitters to fill out the spectrum.
  Reply With Quote
Old 4th June 2014, 02:13 PM   #4
diyAudio Member
 
Refugee1's Avatar
 
Join Date: Jul 2012
Location: Worksop
I have for about 7 years been experimenting with domestic room lighting using LEDs.
The first was 9 Luxon stars in an array to replace an unreliable strip light. This has been very reliable with a power brick from a cash register.
The best reliability will be a laminated transformer with a bucking coil in series with the rectifier to get rid of the charging pulses from the capacitor to keep the core cool. This may not be the most efficient thing in the world but the trouble involved with replacing the power brick every two years is worth the extra energy cost and electronic waste saving will also save on waste removal tax in the long run.
I have been looking into growing plants under LEDs and need someone whom is growing high profit plantings whom will allow me on site to measure what the leaves actually absorb or not.
This will mean that some parts of the spectrum can be left out saving further energy and equipment costs.
  Reply With Quote
Old 4th June 2014, 02:21 PM   #5
wicked1 is offline wicked1  United States
diyAudio Member
 
wicked1's Avatar
 
Join Date: Jan 2008
Location: Midwest
There's plenty of data about what spectrum you need for plants.. Most of the info is on MJ growing forums, but they are serious about it, and some good data can be found. A couple companies make red emitters at the correct wavelength (normal red led's work, but are a bit too high in the spectrum), and the blue is easy to find.
I haven't tried focusing on the blue and red spectrum yet, but that was my initial plan. I just had all these white emitters left over, so used them, and have been happy w/ the results.

Actually, I still have some links saved in my bookmarks..
http://shop.stevesleds.com/Philips-L...S-Deep-Red.htm
http://www.ledgroupbuy.com/deep-red-660nm/

Last edited by wicked1; 4th June 2014 at 02:26 PM.
  Reply With Quote
Old 4th June 2014, 04:23 PM   #6
TheGimp is offline TheGimp  United States
diyAudio Member
 
TheGimp's Avatar
 
Join Date: Aug 2009
Location: Johnson City, TN
I start my sets for the garden around mid February. I've been using "Gro-Lux" FLs with good success, but the idea of using LEDs is interesting in that it might offer better height adjustment as the seedlings grow.

The LEDS have another advantage in that they emit very little UV, so insects are not attracted to the lights.
  Reply With Quote
Old 4th June 2014, 05:57 PM   #7
diyAudio Member
 
Join Date: Dec 2010
Location: Amesbury, MA
So with the data provided it looks as though chlorophyll A is at highest absorption around 425nm where chlorophyll B is closer to 470nm. They both are absorbed to a lesser degree at 650nm for chlorophyll B and 675nm for chlorophyll A.

This is quoted University of Massachusetts article:

"The vital rays for plant growth are blue-light at 450 nm, red light at 650 nm, and far-red light at 730 nm. The 450 and 650 nm rays are required for plant photosynthesis, the production of food from light, water, carbon dioxide through the catalytic action of the plant pigment, chlorophyll. The 650 and 730 nm wavelengths control flowering through light-induced changes in the plant pigment, phytochrome."

Here is a link to the full article.

Univeristy of Massachusetts Amherst:Course Homepage:Template
Attached Images
File Type: jpg Mightex_LED_wavelength_portfolio_July2012_750.jpg (184.3 KB, 110 views)
File Type: gif psnpigmentspec.gif (28.1 KB, 109 views)
  Reply With Quote
Old 4th June 2014, 07:17 PM   #8
wicked1 is offline wicked1  United States
diyAudio Member
 
wicked1's Avatar
 
Join Date: Jan 2008
Location: Midwest
Quote:
Originally Posted by TheGimp View Post
I start my sets for the garden around mid February. I've been using "Gro-Lux" FLs with good success, but the idea of using LEDs is interesting in that it might offer better height adjustment as the seedlings grow.

The LEDS have another advantage in that they emit very little UV, so insects are not attracted to the lights.
Another is that all the light is emitted down towards the plant. You don't have to worry about reflecting 1/2 the light, and all of the losses which come with that. They seem to be about 50% more efficient, as far as growth per watt. And, the plants just look healthier and more natural under them, compared to fluorescents.

Famousmockingbird,
About the spectrum, plants do use blue most, but as far as white LED's go, they ALL have a ton of blue. The LED is a blue LED, and then the phosphor coating adds the rest of the spectrum. So that's why for a single emitter, the reddest possible white emitters work the best. (I think mine are 2700k) The cool white simply don't have enough red. Obviously red LED's would be more efficient than the thick phosphor coating the warm white led's use.

Still, for these relatively inefficient LED's, they're way better than CF's and halides.
They were also easy . Mount one big emitter to an old CPU heatsink, and project complete.

Since there are a lot of engineers here, I'll also mention.. You might notice if you start looking at datasheets, the bridgelux emitters I used have efficiency numbers that are about the same as metal halides, which isn't great. (they might be better by now.. Mine are about 4 years old) But, they work much better due to all the light being emitted in one direction. You do still need a reflector to catch the light at the edges, but it's nothing compared to traditional lighting.

Last edited by wicked1; 4th June 2014 at 07:25 PM.
  Reply With Quote
Old 5th June 2014, 10:11 AM   #9
diyAudio Member
 
Refugee1's Avatar
 
Join Date: Jul 2012
Location: Worksop
What I am looking for in addition to the wavelengths is the power ratio of the three sources of light.
There is little point in shoving out more power than needed at one wavelength while not putting enough out at another wavelength.
That is why I was thinking of using digital photography in order to work out what the leaves absorb at different stages of growth.
  Reply With Quote
Old 6th June 2014, 08:09 PM   #10
diyAudio Member
 
Join Date: Dec 2010
Location: Amesbury, MA
In my own experience to not waste power on certain wavelengths I only use blue light around 450nm for all the early green growth. When plants mature and it's time to flower or fruit that's when I add the red 650nm spectrum in.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not 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 Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Rockford Fosgate BD1000, green led & protect led lit. djmdp Car Audio 5 10th October 2012 04:57 PM
LED Flashlight (SUPER LED BL-X8600) with power P = 3W otherwise adorn751 Everything Else 1 9th April 2012 04:01 AM


New To Site? Need Help?

All times are GMT. The time now is 06:17 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2