# is a 50 watt INCENDESCENT bulb enough for a 10 gallon planted?



## SAMhap (Jun 20, 2010)

setting up a 10 gallon planted. have 2 25 watt incendescent bulb light fixture. is it enough to grow vallisneria, java fern, dwarf hairgrass, chain sword, java moss and frogbit?


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## bae (May 11, 2007)

SAMhap said:


> setting up a 10 gallon planted. have 2 25 watt incendescent bulb light fixture. is it enough to grow vallisneria, java fern, dwarf hairgrass, chain sword, java moss and frogbit?


Don't use incandescents. They will overheat the tank without contributing adequate light. Instead, get a couple of 13watt CFLs, which will do nicely for those plants.

Note that some of the plants you've chosen are fast growing (the vals and chain swords), and will crowd out the hairgrass and each other. Frogbit is also fast growing, but it's easier to thin out. It will shade the other plants, cutting down on the light they get.


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## dl88dl (Mar 8, 2010)

Makesure they are the 6500K 13watts CFLs and you can get them from Home Depot.


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## ksimdjembe (Nov 11, 2006)

dl88dl said:


> Makesure they are the 6500K 13watts CFLs and you can get them from Home Depot.


aka "daylight' CFLs (most of the time have the 6500K rating)


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## BillD (Jun 5, 2006)

They don't have to be 6500K, they can also be 5000K, but only those ones. I seem to have better plant growth with 5000K rather than 6500K.


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## Darkblade48 (Jan 28, 2008)

To be honest, the Kelvin temperature does not really matter. I have grown plants equally well with 2700K, 5000K, and 6500K. Others have grown plants equally well with 10000K bulbs.


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## bae (May 11, 2007)

BillD said:


> They don't have to be 6500K, they can also be 5000K, but only those ones. I seem to have better plant growth with 5000K rather than 6500K.


Bill, where do you get 5000K CFLs? I like that color temp too, but I never see it in the usual places.


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## BillD (Jun 5, 2006)

Home Depot started carrying them recently. They are Philips, and I believe they are called Bright White. They are $14 for a six pack.
I will have to disagree with colour temp having no effect on growth. Plants will grow uder all sorts of light, even incandescent. However, lights in the 5000K to 6500K will outperform lower temp tubes significantly. One factor that may be at play here is the actual amount of light output of the tubes. When I first used Philips Ultralume 5000K, they had a third more light output than regular tubes such as cool or warm white of the same wattage. That is a factor that may be most important, as the light is a source of energy for the plant. As soon as I installed the Ultralumes, plants that had stagnated for a year immediately began to grow.


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## waj8 (Jun 30, 2010)

I am firmly in the Kelvin does not matter camp. Very minor changes in spectrum will result in major changes in Kelvin rating. Kelvin rating is strictly the human perception of the blueness or redness of a lamps spectrum. Plants have no eyes so they don't care. Visually I like 6500K. Like meatatarians though, "it's a personal choice".

People are often fooled by changing their lamps and getting better growth. For one thing lamps are just plain brighter when you first change them. For the first 100 hours or so lamps are up to 10% brighter than normal. For another, if the new lamps have a high CRI rating then they really are going to be better for plant growth. Daylight or Superdaylight or full spectrum or Daylight Deluxe are all examples of high CRI lamps. As an extra added bonus, high CRI lamps also look good.

As far as I know, there is no such thing as lamp phosphors that are extra efficient and produce more plant usable light per watt. There are better ballasts, fixture designs and lamp technologies but all phosphors are pretty much equal in efficiency. IMO people should forget about trying to find the right lamp and focus on the right fixture. Just choose lamps you think look nice.


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## BillD (Jun 5, 2006)

Initial out put of a T12 Ultralume was 3300 lumens versus a cool white, with 2400 to 2600, or a plant/aquarium light with around 1800. This is significantly more light. Higher CRI also. All tubes have a temp graph, which may or may not be readily available, which show where the colour biases are. Interestingly, halogen has a CRI of 100, yet apparently is lousy for growing plants. Also of interest, to me anyway, is that when T8 tubes come out all the specs don't necessarily translate from the T12 version. Case in point, T12 Philips Natural Sunshine has CRI of 92, while the T8 version is only 84, which is less than the Daylight which is 85.


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## waj8 (Jun 30, 2010)

I have read that halogen or incandescent are pretty good for growing plants, just not a good choice because of their low efficiency and high heat output. Never tried it mind you. I would have to think they would be good as the light output is pretty darn similar to sunlight.


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## BillD (Jun 5, 2006)

From what I understand halogen is terrible, although I can't remember why. Incandescent just has the wrong colour temp for good plant growth. They are also very inefficient.


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## waj8 (Jun 30, 2010)

I have to admit you have me thinking.

I have read many times that people have used incandescent lamps to successfully grow plants but I am not sure if it is true. 

Natural daylight is between 5000K and 6500K while incandescent lamps are like 3000K so incandescent lamps are not very similar to sunlight. Both incandescent and halogen lamps are nearly devoid of blue light. Probably that makes them a poor light source for plants even though they are full spectrum lamps. 

I have successfully grown plants under 4100K cool white fluorescents though so I do not think color temperature is a deal breaker at all. In any case though no one should use incandescent lights for plants as it just costs too much to operate them.


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## BillD (Jun 5, 2006)

Incandescent is not close to full spectrum, and as you mentioned has a low K temp. If I remember correctly, halogen is low or devoid of one of the wavelngths necessary for plant growth. back in the early days of the hobby incandescents were the norm. Some plants grew ok (I had great luck with a small Sag) although algae was a problem other plants were hit and miss, as is still the case with good lighting. When the Grolux tubes came out, they were popular because they were supposed to grow plants, but with their pronounced pink cast reds and blues were enhanced on fish. The problem with them was they only put out about 1800 lumens of light from a 4' tube. You couldn't light a room with them. Newer versions aren't much better. I believe that light intensity is as important as correct light to good plant growth.


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## juanitow (Jun 21, 2008)

Incandescents and halogens are no good for plants because of a few reasons. First they're very inefficient.
The most important reason however is that they're disproportionately high in the far red spectrum. Lets say a wee plant has sprouted. It's not getting sufficient light. It should stretch out for light to compete against other plants if it's shaded by them. If it's shaded by a cliff then there's no point stretching. Shades by plants will have a higher far red to red ration than regular shade, so the plant if there's too much far red will stretch.

You'll end up with a skinny stemy plant with stunted leaves.


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