increasing light levels on grow stand

[Ross]

Wow! Can't believe I missed all these posts. I'll try to put my 2 cents (US) in on as many questions as I recall from above posts (when answering, I can't see all the posts

There was a question regarding 24" t5 tube fixtures. Check out .: Sunlight Supply - horticulture and aquarium lighting systems :. Website which is the brand I use in 4-tube 48". There is a 4-tube 24" listed. While they don't say there, I would suggest the 24" tubes are 2500 lumens a piece for 10,000 lumens total (4 tubes). This implies approx 800 foot candles at one foot distance below the lights. Sufficient for Phals and many low-light minis. These fixtures do not include bulbs, so budget in the cost of these as well. They should last at least a year and unlike regular florescents, they don't go dim during the burn life. They just go out.

Forget Home Depot - they don't sell t5. They do, however sell t8 which are pretty bright - just not as bright (or hot) as t5's. They only sell (to my knowledge) 2-tube fixtures. So check the link above for 4-tube fixtures. I personally would skip t8 and go to t5 from a hydroponics store or on-line. Otherwise you may end up at same conclusion I did: "why did I spend the money on t8?"

I grow under 4ea 48" t5 tubes and have considered going to 8 tubes. Yes there is a double light output, however it is spread over twice the area. My Orchidarium is 20" wide so the 20" fixture makes sense, and I figure I am getting about 2000 foot-candles at 6" from the tubes with 4 tubes. This isn't especially high for Phals, just more than they need. I grow mini Dendros and mini Maxillarias as well as Cischweinfias and a bulbo at 3-8" from the tubes and they love it.

Yes, the brightness of the t5's will amaze you when you first fire it up. Keep in mind, the tubes are made to run at something like 95 degrees F. This means the fixture will contribute a fair amount of heat to a setup. Not as much as Sodium, etc. but still a lot. I run a fan under my fixture all the time the bulbs are on to dispell as much heat as possible before it gets into orchidarium. My orchidarium (as I type this right now) is 81 degrees F under the lights and 78 degrees F at the tank floor (29" below the lights). I have been running the through-wall fan today otherwise the difference would be more dramatic.

[Lagoon]

I have a plant stand I bought about 20 years ago, It came with T12 lights. Over a year ago I took out the T12's and put in T8' lights, 2 tubes per level @20watts each.
I have bloomed phals, paphs, oncids. So they can work out.
If you add some CFL's you can bloom higher ligher orchids, such as catts, dens etc ...

[Phallgirl]

Well went to HD for T5 lights 24". The man in lighting dept wasn't much help. He wasn't getting it. I bought a T5 (they only had one). I went to OSH Garden suppy and they had "sunshine" tubes with even more lumens of output still at 20 watts. So I bought 2 of those. I think I need a new light meter because there wasn't any change in the reading. But what I have learned is that T5's are smaller, skinnier more compressed gas tubes and so they make more lumens at less watts. WHAT? I hope that's right. I have to look up lumens vs foot candles now.

[ladyslipper]

Originally Posted by OrchidTess

I switched from regular fluorescents to T-5's and WOW the brightness difference is amazing I was growing Phals under 4 T-5's (leaves and roots were turning red or yellow leaves on the violacea types) but I made another plant/light stand using 2 T-5's seems much better.

Hi there Tess, would you please tell me the size of the ballast of your T5 tubes? I grow both phals and the violeica types and currently have 2 40 watt, 48 inch tubes that I think are a T8. I am pretty sure the light isn't sufficient even with the east window nearby. I was planning on cannabalizing my current set up to include lighting such as yours but I don't know if the measurements will be right.

regards, mary

[Ironwood]

4 foot 54 watt T5 lamps have their own unique pin placement for mounting so you would be much better off to get complete fixture designed for T5 lamps. T5 lamps have an electronic ballast that makes them more efficient. Another advantage of T5 lighting is the fact they only loose about 5% of output throughout their life as compared to 30 to 40 % loss for other fluorescents and HID systems. The lamp life is 20,000 hours, twice the life of other fluorescents.

I grow catts under these and it is almost too much light for them (red in the leaves) and the lights are more than 3 feet above the bench (about 1900 to 2000 foot candles at bench), also have mylar on walls. Some oncidiums turn very yellow and it will stunt their growth from the 14 hour cooking I give them under these lights.

4 T5's with the proper reflectors would provide enough light to grow phals 8 to 10 feet away from lights.

[ladyslipper]

Hi Ken, sorrry. I just read your reply regarding the T5 lights requiring a special ballast. My grow area is really small and I could not have the plants more than maybe 1 or 1.5 ft below the light. If I had 2 tubes, that woudl obviously reduce the amount of light so maybe my phals wouldn't fry?

here is a picture of my grow station from lee valley tools
http://www.leevalley.com/garden/page...,44716&p=10549

I thought I might be able to remove the lights that came with the unit and put the fixture the T5's required?

mary

[Ross]

Originally Posted by ladyslipper

Hi Ken, sorrry. I just read your reply regarding the T5 lights requiring a special ballast. My grow area is really small and I could not have the plants more than maybe 1 or 1.5 ft below the light. If I had 2 tubes, that woudl obviously reduce the amount of light so maybe my phals wouldn't fry?

here is a picture of my grow station from lee valley tools
http://www.leevalley.com/garden/page...,44716&p=10549

I thought I might be able to remove the lights that came with the unit and put the fixture the T5's required?

mary

I would think you could do this with 24" 4-tube t5 fixtures (at least when I looked at your photos I said to self "I could do this ")

[Ironwood]

Hi Mary, if you are growing Phals. only, your present system should work fine. Remember the effect from the light is cumulative, so if you run the lights for 12 to 14 hours a day with steady 600 foot candles, it could average out to more than a plant in nature that receives 2000 foot candles for a little while through midday. This light level would drop off quite dramatically in morning and late afternoon. Also remember there are no cloudy days under lights.

One other important thing to remember is to replace the bulbs for fluorescent and HID at about 70% of their life expectancy as the output is now down to 60 to 70% of a new bulb. If you are trying to light a warehouse this is not a big deal, but if you growing plants it matters. T5 high output bulbs are the only exception as they operate at about 95% output throughout their life.