# led grow light

#### lisa34125

Joined Dec 8, 2011
1
hi, everyone,what do you think of the led grow light for plants?

#### Meixner

Joined Sep 26, 2011
117
Flourescents have a lower cost per lumen.

#### Wendy

Joined Mar 24, 2008
22,541
We have a slew of projects on just that subject. If you do an advanced search (the regular search on AAC doesn't work very well) you will get many hits.

Tell us what your thoughts or needs are and we can probably help.

#### Wendy

Joined Mar 24, 2008
22,541
Flourescents have a lower cost per lumen.
Are you talking up front costs or electricity cost? Fact is, LED are as efficient compared to flourescents as flourescents are to incandescent bulbs by any measurement. Which is to say, I strongly disagree with the above statement.

#### mcgyvr

Joined Oct 15, 2009
5,394
Which is to say, I strongly disagree with the above statement.
Me too. Flourescents are one of the worst when it comes to growing plants/cost/color spectrum/light output. LED's will win over flourescents as well as other light sources like metal halide/hp sodium when you factor in all the costs.

Joined Dec 26, 2010
2,148
The situation with regard to the efficacies of different light sources is in a state of flux. Mercury lamps are a mature technology, some would say nearing obsolescence, but LEDs are up and coming.

At one time it would have been true that fluorescents were actually more efficient (let alone cheaper). Now fair LEDs are at least comparable, good ones can be better. First cost is another matter: at least where I live LEDs are still pretty expensive. For general illumination they do not yet seem competitive with the likes of CFLs, but this seems likely to change.

When it comes to getting a tailored spectrum for something like growing plants though, it seems likely that LEDs win out. They also start up quickly, and unlike many discharge tubes they can in principle be dimmed with PWM (although some packaged LED lamps cannot).

#### Jotto

Joined Apr 1, 2011
151
I am sure that I have a bunch of high bright LEDs here. As we get rid of machines I will start pulling them and list them on the flea market site. I will not be adding pictures since I will be giving them away for free and its hard to post pictures here because it allows for 97kb file size and I have to always crop for them. Now if it would allow me to post just from the original pictured I would be willing to, but I have limited software here and its a pain for me to do.

I remember at one time using fluorescents you had to use a couple of different lamps to produce as much of the spectrum possible. Would the same be said of LEDs? Of course a small package of LEDs would be much better then fluorescents. The LEDs we are using are surface mount. Another point that needs to be mentioned here is the heat when soldering the LEDs. If your using regular solder you could damage them when installing. This is where paste is going to help. Low temp solder paste is the way to go. Also they degrade just sitting there new in the package. Digikey has a spec sheet on them, proper storage and temp for soldering.

http://www.cree.com/products/pdf/XLampMX-3s.pdf

#### JingleJoe

Joined Jul 23, 2011
186
Interesting relevant sidenote:

Green plants only absorb the red and blue wavelengths of light so you could use red and blue LED's for snazzy lighting effects and less power would be spent making wavelengths the plants can't even absorb (I'm looking at you white LED).

#### jimkeith

Joined Oct 26, 2011
540
Interesting relevant sidenote:

Green plants only absorb the red and blue wavelengths of light so you could use red and blue LED's for snazzy lighting effects and less power would be spent making wavelengths the plants can't even absorb (I'm looking at you white LED).
Thanks, never knew this

#### jameslongenecker

Joined Nov 29, 2011
1
Thanks for the post.

#### Meixner

Joined Sep 26, 2011
117
Are you talking up front costs or electricity cost? Fact is, LED are as efficient compared to flourescents as flourescents are to incandescent bulbs by any measurement. Which is to say, I strongly disagree with the above statement.
__________________
Im talking up front costs. However im assuming the OP is talking about a large setup capable of growing many plants.
If he is only planing to grow a few plants LED's would then be cheaper.

Last edited:

#### Wendy

Joined Mar 24, 2008
22,541
Actually that isn't true either, which is why we get a lot of questions on the subject. If you DIY the components are a lot cheaper than buying a finished product.

Someone who is a decent fabricator can build it very cheaply, and save money on electricity too.

One of the classic problems is the cheap stuff dying way too quickly due to shoddy construction. The typical life span of an LED runs between thousands to 100's of thousands of hours. It doesn't have to be this way.

#### mcgyvr

Joined Oct 15, 2009
5,394
If you DIY the components are a lot cheaper than buying a finished product.
Thats the truth.. I built a LED fixture for my coral reef tank and it cost me a little over $175 USD.. Comparable "store bought" units run between$800-1000 easily

#### Lundwall_Paul

Joined Oct 18, 2011
228
I would start by figuring out what wavelength of light that plants need and like. There is a chance that LEDs don't meet the plants needs.