These compact pin-fluorescents are new to me. I don't know much about the fixtures.

Is the balast/electronics in the base of the bulb (like a screw-in fl) or in the fixture? Do the fixtures hum like older tube fixtures?

I see one web site recomends warm light (2700 degrees) for flowering and cool light (6500) for vegetative growth. What do you know about choosing bulbs?

I'm really interested to know how energy-efficient these bulbs are. Ideally this should be expressed as a percentage of power emmitted in the useful spectrum as opposed to heat or infared radiation. Are they better than standard fluorescent tubes? Do they drop in output over time? I see ratings like "10,000K" and I don't know what this means. Other bulbs are rated in lumens and some people talk about foot-candles. Do you know how to convert lumens to foot-candels, etc?

For large fixtures, that the old-style 48-inch x 40 watt tubes and fixtures are so very innexpensive that I like to use them. With newer electronic ballast they are supposed to last forever almost.

More advice on cf and other non-houshold bulb types is apprecieated.

----David

Here is a link that might be useful: my terrarium

David, in Danny's pictures, you can see on the top of the fixture that the ballasts are mounted remotely from the bulbs. These are called Bi-axial compact fluorescent bulbs, I believe. If the ballasts are magnetic, they may hum a touch. If electronic, or better quality magnetic, then they probably do not hum.

Most of use use Lumens as a figure. Footcandles and lumens don't convert over, exactly, as they are measures of two different characteristics of light(AFAIK, I may be wrong).

I have grown and flowered many of my orchids under a combination of cool white(~4100K) and daylight(~6500K), so I am of the opinion that this "X bulb for Y purpose" myth. This is just an opinion(and we know how those are), and has no basis in scientific fact or anything. I now grow exclusively under 6500K bulbs, and everyone seems happy and I have another orchid in spike.

The 2700K,4100K, and 6500K numbers refer to color temperature. It's really just a way to describe the color of the light to humans. 6500K is considered sunlight-spectrum(I think it was described as sunlight at dead noon). Anything less than 6500K is more red, and anything more than 6500K is more blue.

I hope I got everything and I hope I was accurate enough to not mislead you.

Sam

Lets see if I can answer some of David's ?'s.

(1) The bulbs run off of remote ballasts-they're silent. They do not screw in, and have a 4 pin arrangement.

(2)I like to mix 5000K-6700K bulbs. 5000K produces a yellowish, tropical light, and the light gets crisper and whiter as you move up.

(3)10000K is kinda like ultra purified sunlight-but its relativly useless for plants.

(4) The big advantage for these things is that watt for watt, they produce way more light than normal tube bulbs.

Here is a link that might be useful: Best place to buy them.

Don't worry about getting noisy or flickery ballasts. All T5 fluorescents - 5/8" diameter fluorexcents - (including the kind bent into compact fluorescents like these) specify electronic ballasts, which are cooler, smaller, quieter, and more efficient. Unfortunately they cost more, but it's really a small price to pay.

That's quiet a fixture! Your utility bills are gonna be scary.

I have also heard that plants need more red light in order to bloom, and I consider this absolute bunk. My plants do great with a constant light 'temperature' (spectrum) of 6200-6500K, blooming and everything. And if you think about it, when is the sun ever that red? It won't be until it becomes a red giant, and that is eons from now, if the earth lasts long enough for us to experience that. So anyways, just try to get as close to natural sunlight as you can, and you're good to go. 10000K is really meant for aquatic plants, because blue light penetrates water the best. And even then, it's mostly only used for marine tanks, because it does make things look very blue, which most people would consider to be undesirable, unless you like that 'otherworldly' look, or have corals that you want to see fluorescing.

You can use the regular cheap shoplights for plant growth. I used to start seedlings under them for a few years (when I lived with my parents and could use their basement!). They aren't as good though, and have to be a few inches from the leaves of the plants. So I think they're better used for starting seedlings than for an aesthetic terrarium set-up, where you can't have all the plants 2" from lights at all times. T5s are much better than T8s (the standard fluo's), so get those if you do go with normal fluos, and get VHOs if you can. They are almost as good as compacts.

As for a higher electricity bill, not really. Fluo's use hardly any electricity compared to incandescents, and think of how many people leave lamps on (with incandescent bulbs in them) all day long. A metal halide would make a very noticable difference in your bill though. And I would know, since my husband has a 400W MH on his reef tank. =)

The sun is currently approximately a 6000K blackbody:
http://climate.gsfc.nasa.gov/~cahalan/Radiation/SolarIrrVblackbody.html

10000K lights are made because water filters out most of the visible light, leaving only the UV range (which is why most fish are only colourful and see in the UV range). In a marine tank people can't afford to put things down 5m, so we use lamps with shifted spectra instead.

Chlorophyll is green, which means it reflects green and absorbs red and blue. Thus the light you want is red and blue (pink).

Power consumption is simply the number of watts * the length of time operating: A 40W light uses the same amount of power whether it is a light bulb, a LED array, a halogen downlight or a fluorescent tube. However, the amount of light available for those 40W changes. A fluorescent light will give you more photons per watt than an incandescent, a metal halide even more, so if you want lots of light you are better off with a 100W metal halide than a 100W fluoro array.

Thanks for all the usefull replies. I will use compact fluorescent if I make another large terrarium. I agree that it's worth the extra money spent, if you know what you are doing and why you are spending it. My current setup is low light, and shade plants bloom nicely. If I go to brighter light, the plants can grow more densly, and I have many more options in what to plant. It will be important to keep the heat down though.

----David

My husband just told me last night that some T5s, high output T5s, are actually brighter than compacts. Added benefits include more even lighting across the terrarium, sustained light output throughout the life of the bulb, and you can buy a complete kit (if you live in Edmonton, Alberta) that includes a special reflector, bent perfectly for maximum reflection of the T5 light. Unfortunately, this is a local company, and they make the reflectors and everything themselves, so the rest of you won't be able to buy this exact kit. But perhaps a local business would sell something similar.

Tell me more about the T5s...I have heard of them but don't know exactly what they are. Are similar to VHO?

For light geeks !!!!!
More web research: fluorescent tubes:
lpw means lumens per watt, a measure of efficiency
cri is color rendering index--evenness of the light spectrum.

T5 is 5/8 inches diameter -- 75-83 lpw. higher watts per tube
T8 is 8/8 inch or one inch diameter -- 92 lpw
T12 is 12/8 but actually 1.1 to 1.6 inch diameter, high lpw. 4-ft is 40 watts

metal halide -- 75-83 lpw, rapid loss over time.

HO=high output. VHO=very high output. These have modestly higher watts for the same size tube, and include T12's with special fixtures.

CF is compact fluorescent, brighter than VHO at 110 watts for 4-ft tube

There is also a T6-1.1 inch diameter and a T10-1.6 inch diameter, and a single-pin configuration.

I also notice that specialty bulbs can be much lower light output. for example, high color-rendering-index "daylights" have very low lpw. I think they filter out peaks in the spectrum.

F40T12 (40 watt, 48inch) 4000K, are still $1.50 each an any local hardware store, complete fixtures are $12.00 with two tubes.

----David Fourer

T5s would be similar to VHOs, but as you can see from David's post, VHO doesn't have anything intrinsically to do with the size of the bulb. You can get T8s and T12s that are VHOs. For some reason that I don't know though, T5s, although they are a smaller (slimmer) bulb, have a higher light output than T8s and others. They are also more attractive, since they are so slim. And of course this would also mean that you can fit more of them into a light fixture. But, they are more expensive. However, I think prices will come down, as more and more people are hearing about them and want to use them. I believe you can get them in any of the standard tube lengths (18", 24", 36", 48", etc.).