I am glad someone asked this as I was wondering the same thing. In fact I very nearly posted the same question (except for the "friend's Halogens" part) 2 days ago but could not log in from my office computer for some reason and had left my personal laptop at home. Funny coincidence! Since you asked I hope you will not mind if I piggy back my questions as well?

When I was making a phone/internet purchase from a pretty well known grower in the Twin Cities area I asked for advice about artificial lights. My collection was growing and I was expecting I would very soon need some supplemental lights to help my collection along through the long dark northern Wisconsin winter. He suggested those quartz halogen track lights as well. I was a little skeptical and happily found this web site and have been using ODNO 4 foot T-8s and high watt CFLs with great success.

I was just thinking about this because as I was moving plants inside from their summer holiday I realized I needed to make up some more of those ODNO T-8 fixtures to light up the added indoor shelves, and also was planning to expand on my CFL use. As an aside I did end up buying the Farmtek 125 watt with housing and bulb for a really good price. It was less than some are selling just the housing for and comes with both mogul and medium base included.

After being unable to post and not finding any useful info in the "Growing Under lights" forum I looked at a couple of manufacturer web sites in order to find the spectral analysis of the output. I had a hard time finding that specific info but did get a little useful data from the GE site on the 500 watt utility type bulb.

The color temp for most was around 3000K but the lifetime rating was astonishingly bad, most would have to be replaced monthly or more based on my lighting schedule. Then there is the heat generated, though I expect it is not too different from the HID type bulbs. I saw on the GE site a surprising variety of options in this family but did not readily find a spectral analysis of these cheaper stage/utility type bulbs which was what I was looking for at the start. They are sure cheap enough but I think they are so inefficient as to make them a less desirable option in my case.

When the grower suggested those little parabolic type track lighting sources, most of which were rated at 25 watts I was a little concerned that it may be enough light to see the nicely but not enough light to be of practical use to the plants.

So, I am anxious to here what the experts here think.

Would it be bad form to post this same line of inquiry over in GUL? I know some Orchid forum regulars have posted there as well.

Richard

Richard,

I think we're getting advice on lighting from the same person. Coincidentally, two days ago I was at the retail store of the same "pretty well known grower in the Twin Cities area" and the owner mentioned that he used halogens to light his orchids at home. He said that the halogens he used were inexpensive and did the job.

"Then there is the heat generated, though I expect it is not too different from the HID type bulbs."

There is absolutely no comparison. A 500W halogen is so extraordinarily hot as to be very, very dangerous. In most places they are now illegal, even as worklights which was always their main usage. In my younger crazier days I did use one suspended over a 4'square table as a cheap source of artificial light for a basement setup. I lived in dread that I would come home to the sight of volunteer firemen rolling up their hoses, poking about in what was left of my apartment. I don't remember how many lumens you get from a 500W halogen but it isn't more than you can get from a 105W CFL!! The CFL will be practically cool to the touch in comparioson. And if you want to compare directly on wattage, a 400W HID is nowhere as hot as a halogen, not even a 1000W HID is as hot as a 500W halogen.

Sadly, it does take those kinds of wattages from halogen/incandescent sources to provide meaningful amounts of lumens. The two 50W halogen are not exactly useless and it is arguable that incandescent (halogen) light is in many ways superior to fluorescent but as they are mainly being used as supplemental lighting, for the power they consume, better options are available. One option is to replace one of the halogens with a 42W CFL. The mix of CFL and incandescent wavelengths IS sunlight. You can't get better light quality than that at any price. Two 42W CFL would use less power than the halogens and give lots more lumens. Quality issues are moot since there is plenty of natural light available.

Any lamp does better bulb life wise if you minimize the number of on/off cycles per day. A single 8 hour run is much better than two four hour runs. Since the E/SE exposure favors an afternoon bulb run, set the timer for a noon or 1pm start and 8pm shut-off and call it good.

H

On the GE site the 500 watt T3 bulb used in most utility type lights has a color temp of 3000K to 3200K, initial lumens of between 12,800 and 13,250 and a rated life of 400 hours or less. They cost b/w 4 and 6 dollars a "pop".

The typical low voltage track lighting type halogen bulbs (MR16) were in at around 500 lumen.

One MR16 bulb did boast an astonishing efficiency of something like 260 lumen/watt, putting out 10K plus lumen for the 50 watt bulb. It was I think designed for a projector though and not a track/indoor spot application. I bet it gets pretty hot!

I am glad you clarified the HID - heat issue Howard, as I was considering a HID light source at one time but thought the heat from the ballast and bulb would be too great for our living area. That and the sense I had after reviewing many many posts here on the topic of lighting was that HID lights may not be as cost effective for my purpose when compared with CFLs and the ODNO T-8s. I have been happy with that decision so far, and have you and others here to thank for the guidance obtained from many current and past threads.

Richard

Richard - Highjack away. Your info is helpful to me.

Howard - at my friend's, how close to the plants would the 42W CFL(s) need to be to be effective? The track light fixtures are 3' away from the shelves. Also, they're set at an angle, which means the 2nd shelf gets some light but is about 5' away from the track lights.

The puzzling thing is a couple of the Phals that bloomed once a year at my house have been in continual bud/bloom for about a year now at her house, and other plants have bloomed 2x year to the 1x @ my house. It's been discouraging to me - our windows face E/SE, and I think... if only I had her light set-up....

I'm assuming the larger the CFL in those track light fixtures, the better, as long as they fit and don't blind my friend, her DH, and the cats? Unless the distances of 3' and 5' make them ineffective -

Thanks much, Whitecat8

If it is a 12V track system the CFL will not fit. They may not fit even if it is a 120V system as the 'cans' will likely be too small. However, a 42W CFL has well over 2000 lumens coming out of it. Both the CFL and the 50W halogen have to be 3' from the plants, yes? Both are 'point sources' so the same rates of intensity square law light fall off apply to each. So... given all that, if you were one of those orchids on the shelf (especially the 5' distant shelf) which light would you wish your grower was using?

H

Uh, I'd wish my grower was using the 42W CFL? Is that the right answer? LOL

Thanks much, Howard. Because my own 42W CFLs have been 18"-24" from my plants, and I'm sitting here gritting my teeth about the 3' distance, I'm envisioning this spreadsheet that lists the main lighting solutions, lumens, warm/cool, distance from plants, etc. for the FAQs.

Every time there's a lighting question, it's difficult to go back through the archives, assimilate the comparative info, figure out what info isn't there, and then compose a coherent post. Now, a spreadsheet would solve ALL those problems, right? (not, but it'd help)

I'll pass along the info to my buddy. Whitecat8

Jeez I am using the 42's and 85's a lot closer than that is that bad? Am I losing?

I haven't had any protests from the plants. Even with the west window & the 85 w. The vanda's like it. Open the top of the window to vent some heat out

Clara

I too would be interested to know what the optimal distance from CFLs would be for those plants placed in the center of light's beam. I am thinking of supplementing the light in my south window this winter with CFLs.

I'm using CFL's (42,45,85 Watt) with several 4' set ups as well. I've moved my plants closer to the bulbs (3" min, 24" max) with overlapping fields of bulb placement. Move plants a little closer (not all at once) and watch for signs of light or heat stress (I've burnt leaves touching some bulbs). Plants getting more light need more watering or humidity. My only Vanda hangs between 2 CFLs and always seems dry now, the outermost plants are seedlings, Phals and others getting the shadier spots. I also rotate some plants closer to bulbs for a month or so just to see how they do.

Shaun

Shaun, your plants are as far as 4' from the bulbs? If that's the case, the light from CFLs must be stronger than I had imagined.

Thanks,

Mike

I have been seeking advice about CFLs from various people in the last week or so, and someone had suggested that I shoot for about 200 watts per square yard. It makes sense to me to think about lighting my plants according to the size of the area I intend to light, but I thought this figure was interesting. Any thoughts or opinions about this?

First thing Mike, the way I read Shaun's post, he is not saying that he has plants 4' away from any of his lights but that some of his light setups use the 4' tubes. Distance from bulbs is usually a foot or two sometimes more but rarely more than 36". Distance from tubes can be as little as 2" with 6" being optimal, rarely is more than 12" recommended.

Fluorescent tubes and CFL are the same in efficiency. HID lamps are much more efficient than fluorescent but they are more expensive. I also like the concept of using an illumination benchmark based on the growing area size. Planted aquarium and reeftank keepers use a 'watts per gallon' recommendation that is basically the same thing. I would use square feet vs square yards since more people think in terms of square feet than not. If anybody mentions square meters I'll frown.

For 9 square feet under HID a 250W lamp would probably be recommended. With CFL you might want to add another 100W to achieve the same amount of lumens. So the 200W figure is a little low I think, however, if we are talking about a growing area that gets some east or south light the 200W figure is quite reasonable.

H

Thank you Howard. The area I intend to light does receive southern exposure, so I think I will start by trying for the 200w figure and go from there.

Thanks!

Mike

Howard - So, if my shelves are 2' wide and 6' long, I'd need 2 CFLs of 350W or so. Does that sound right? Thanks, Whitecat8

This is a fantastic thread! I have a 60W CFL and it's incredibly bright, but it sounds like it's probably only able to efficiently light 2 square feet.

By the way...has anyone else noticed that while doing research/shopping for these grow lights, one stumbles upon a wide variety of hydroponic and other gardening communities specializing in a rather unique and special crop? I was asked at Home depot when I was buying PVC piping to build light frames whether I was gonna be starting up a reefer den...

I noticed that too - I must say, those folks have good information about lighting. :)

And 'they' are much less resistant to the idea of using lots and lots of lumens in their 'growth chambers' despite the fact that most invest way less in the purchase of seedlings than most of us orchid keepers do on mericlones and divisions. Whitecat, Calvin is essentially correct, horizontal coverage of two feet is just about right. So the 2' depth of your shelves is adequately oovered by a single bulb but the horizontal span of 6' requires three bulbs. They don't all need to be 85W or even 125W it depends on the plants you will grow. You could have a 42 and 85 and a 125 and sort the plants to suit. Or three 42's for that matter.

H

And to confirm, I should be looking for lights in the 5,000 k color temperature range?

Btw, this has turned out to be a very useful thread, so thank you everybody, and thank you Howard for generously sharing your knowledge about this subject.

-M

So I've been doing some research which I'd thought I'd share, and anyone who has any alternate advice/wisdom please feel free to add/correct.

I think I'm going to make the investment by buying a 4 foot long T5 fixture that holds 4 bulbs. It's around 200 bucks (including bulbs and 2 spares), the replacement bulbs seem cheaper, it fits my grow area which is more of a longish area rather, making it difficult to use the CFLs (point-sources of light) and it seems like a really good long term investment. Plus, at around 250 watts, it'll come down to about 10 dollars a month if I run em 12 hours a day. The output is rated around 20k lumens. I'm not too sure how to calculate foot candles, but assuming the plants are 6 inches from the lights, that should provide the 2000fc needed for good growth, right? My 'high light' grow area for the catts and dends is only 4 feet by 2 feet. Then I think my crappy T8 shop-light along with my existing 60W CFL can be moved down to the bottom shelf to light the phals.

WC8 - you seem to have a longish growing area too - would T5s be more efficient? I think 4 foot T5s cost about 5-6 dollars each to replace, whereas CFLs at 42 watts are like 15 bucks a pop. Plus, you'd probably have to buy lamp-shade type things to focus the light for the CFLs, unless your plants are being grown in a room where people won't mind the piercing white glow.

If you are getting 20K lumens from the T5 hood it is an HO ballast which makes sense because those are by far the most popular kind. They are, however, only 1.5 times as powerful as the standard kind (T5 or T8) so to get 2k footcandles you need to go to VHO ballasts. I just don't see the attraction of the T5 for a horticultural application. If you are growing only seedlings and more to the point only the same kind of seedlings then the uniformity of a bank of tubes (T5 or T8) has some merit but a hodgepodge collection of different species and hybrids with different heights, some in spike, some mounted, some out of the pot and crawling away... it just cries out for a single or few very powerful light sources from which varying levels of illumination can be obtained by changing the distance to the light source(s).

H

Howard, I think you're right! But I'm just wondering - 2000fc isn't quite at naturally occurring light intensities, correct? So if that's the case, and it's the maximum amount of light I can ever hope to achieve inside, then won't it be the best alternative for my very high light plants as well as my medium light plants?

In regards to reflectors for CFLs, my 65W CFL doesn't have a reflector. I saw in a past post of someone using vents to make cheap reflectors. I'm thinking this would be a bit better for distributing the light over a long surface rather than a lamp-shade type, which would waste some of the light?

Howard,

Thank you so, so much for boiling down a ton of info to your suggestion of 3 CFLs for my 6' shelf. I'm acquiring more higher-light plants, so 3 higher-wattage CFLs sound perfect for the top 6' shelf that's up against the windows.

The lower-light plants have been doing fine on the bottom shelf w/ plain ol' T8s.

Many thanks, Whitecat8

Hi Whitecat,

Can I ask you which size CFLs you're using?

Mike

Hi, Mike,

So far, just two 42W CFLs from the local Home Depot. Last winter, they were fine for Phals, Phrags, Paphs, etc. that weren't close to the window.

This year, though, I'll go online and get maybe two CFLs somewhere between 250W-350W and maybe one 100W.

Hope this helps.

Whitecat8

Hi WC - I was just wondering about your CFLs as well, since I think I'm going to add to my current single CFL: how are you mounting them? Do you have them hanging from the ceiling? and are you using reflectors?

Hi, Calvin -

The two 42W ones are in those ugly, round, shiny metal reflectors that clip onto things - also from HD. The bulbs don't protrude from the edge of the reflector - nice.

One fixture is clipped onto a bookshelf that happens to be right there, and the other has its cord threaded around open spaces in the plant shelving because there wasn't anything that it would clip to and stay.

I haven't researched fixtures for the humongous CFLs yet - let me know if you look into them, too.

WC8

Hi WC8,

Would you be willing to share your source if you end up finding a decent deal on the big humongous CFLs? In Minneapolis there is a Hydroponics shop that has the big CFLs, but they are quite expensive - maybe comparatively they're not that bad, but I need to find something to compare them to first.

-Mike

Here is a link that might be useful: CFLs at

Hey guys,

So I found some really cheap 125W CFLs on Ebay....they're like 30 bucks each, but maybe the quality is really bad. Does anyone know how much quality can differ for these bulbs?

I happened to visit a hydroponics store close to where I live and they sell 27 dollar reflectors. I can't list their link here because of garden web policy, but if you go to http://www.ruztan.ca/product_detail.asp?menuID=4&SID=28&PID=273
except replace the 'r' with a 'b' and 'z' with an 's', you can see the picture of what I'm talking about. They are white and seem pretty good. Maybe you can find something similar online/close by where you are? I'm really glad these are so much cheaper than I originally expected...and I can use them if I get higher wattage CFLs or even metal halides. I do need to buy a mount of some sort to get the bulb mogul attached, so some assembly is required.

Sadly, I measured the light levels of my horizontal T12 tubes and they are only putting out a dismal 300 foot candles, at 6 inches away. The 65W only produces around 1300 foot candles 6 inches away...combined, along with natural sunlight, I think I'll be able to hit 2500fc (I will measure tomorrow). Which is so weird because the 60W incandescent was putting out 4000fc at 6" away, and I was certain the 65W fluorescent was brighter. I do notice that CFLs get brighter 2-3 minutes after they've started running.

Btw, I feel SO empowered with this new light meter and I'm going to spend tomorrow running around the house looking for the brightest places!

Hey Calvin,

After I bought my light meter I became very obsessed with measuring the light around my apartment during all the sunlight hours of the day. It was also interesting to gradually learn what certain light levels "looked like" after testing them with the light meter.

Mike - Yep, I'll pass along any bargains there may be out there, or just what I end up paying. WC8