# LED lighting and plants



## OrangeAugust (Jul 23, 2012)

Does LED light promote plant growth like fluorescent lighting does? I bought a LED desk lamp last night for my girl's tank, and it's brightness is 800 lumens, I think. It's actually a lot brighter than I expected- I think it might bother her. But anyway, does LED light promote plant growth? I have problem in all of my tanks because I have low light so stuff doesn't really want to grow. I like the way light LED lights look a lot more than the yellow of the fluorescent bulbs (although apparently you can get them in cooler light, which is around 4000 K, but I can only find the 1700 K which is the "warm" looking light).
If LED lights will promote growth, I will definitely use it in more of my tanks. I have a feeling I'll have to get more Hornwort to float on the top of Lila's tank, though to make the light less bright. She got stress stripes when I turned the light on. :-?


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## leafythegreat (Aug 17, 2012)

My 8-gallon has an LED light, and the Hygrophila have been growing like weeds! It's not a very demanding plant, but it seems to be doing really well with just the LED lights and the natural, indirect sunlight in my room.

EDIT:  Check out this post on plantedtank.net. People use LED lights for reef tanks - which, if I'm not mistaken, are the most demanding kind of tank as far as light requirements are concerned.


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## OrangeAugust (Jul 23, 2012)

Cool, thanks!


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## kfryman (Nov 7, 2011)

It depends if it is low quality. High quality will grow awesome, say like the Finnex fixtures.

Both those temperate ratings are way too low for growth, you need something around 6500k to simulate natural daylight.


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## OrangeAugust (Jul 23, 2012)

Thanks, kfryman. I have a few more questions then...
Are lumens related to the K rating? My LED lamp didn't have that K number. It just said 800 lumens.
Also, Why is it so hard to find a compact fluorescent bulb higher than 1700K? What kind of bulb do you use? I have a 1700K 13 watt/60 watt compact fluorescent bulb in the hood of my 5 gallon tank. I don't like the color of the light. I haven't been able to really keep any plants alive except for this one plant that I don't even know the name of. Even my dwarf hairgrass is dying... I've had some hornwort for about a week, so we'll see how that goes. A couple pieces of it already had some brown on it when I bought it, but the rest of it is still green. It's definitely not growing an inch a day though, like I read some other peoples' has. lol.


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## SpookyTooth (Dec 23, 2011)

I use an LED light fixture and can honestly say that it has provided me with better plant growth than my various CFLs of different wattages have. It's all down to quality, kelvin rating and coverage (in my opinion). My LED strip light is specifically designed for aquatic plants and while more expensive in the short term it is more cost effective (electricity consumption and bulb cost wise) in the long term. LED grow panels are claimed to last at least ten years (fifteen with higher quality models) whereas CFLs need replacing ideally once every six months, bulbs can range from a couple of dollars each to higher amounts for more watts.

As CFLs are used and often marketed as energy saving bulbs to replace incandescents it's very common for them to be offered in a colour referred to as "warm white", this is a very similar glow to incandescent bulbs. Warm white refers to a low kelvin rating (between 1700k and 2700k if I recall correctly), what you're after is daylight white or bright white (which ranges between 5600k and 7000k). If you can't find a kelvin rating look for a colour rating, warm white and neutral white should be avoided.

To be honest I haven't done much resarch into lumen output and plant growth but I do know that you really need the right bulb in order to get decent growth to start with. Plants can only "see" higher kelvin ratings and 6700k simulates natural daylight to a good degree.


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## Silverfang (Mar 25, 2011)

be wary about LED lights. Most that will provide the light needed are very VERY expensive. Having said that, I do use one and get nice growth. I use http://www.petsmart.com/product/index.jsp?productId=11000158&lmdn=LIghting+%26amp%3B+Hoods
this light. It provides adequate lighting for cabomba, some hygro, and two swords.


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## OrangeAugust (Jul 23, 2012)

Silverfang said:


> I use http://www.petsmart.com/product/index.jsp?productId=11000158&lmdn=LIghting+&amp;+Hoods
> this light. It provides adequate lighting for cabomba, some hygro, and two swords.


Cool. Now how do I use that? I mean, I would probably use that for my 2.5 gallon tank. The tank just has a flat glass top... Do you just set the fixture on the glass? I mean is the bottom where the lights are flat? Or would I have to get some kind of hood?


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## kfryman (Nov 7, 2011)

I coyldnt find a 6500k bulb at my Home Depot, but I went to a hardware store across the street and they had 15 and 20 watt bulbs. They were the GE brand... Only $7 for the 15 watt. Not only is the light important, but way more important is the reflector quality, LEDs are different with this, a Zoo Med T5 reflector is Crap compared to a Tek fixture. With the same bulbs you can have low-medium light with the zoo med fixture at a given height and the Tek fixture can give out high light at an even higher height. So reflectors on normal lights are super important.

Dwarf hairgrass is a intermediate plant, it needs good fertile substrate, CO2, and medium-high light. Just having a powerful bulb doesn't mean anything, you don't have the proper Kelvin rating and way too high wattage of a bulb. In my 5.5 gallon tank I am trying my hand at hairgrass and was advised to have my 15 watt light at 24 inches above the substrate for medium light.


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