4 foot T8 tubes.

[bogdan]

Hello forum,

Lately I've been thinking about growing some orchids under fluorescent tubes, in lack of windowsill space and also because African Violets and Streptocarpus simply thrive under lights.

I gathered some good info regarding lights using this forum, but still haven't answered some of my questions so here it goes. I know this might help others too, who are in my situation and cannot afford paying 80 bucks for a double T5 tube fixture, instead of buying a 10$ one for T8s (at least that's the situation here).
Would 2, 4' T8s manage to grow phalaenopsis seedlings and 4 of the T8s bloom them? They would be close to the plants (3-6").
The 54W T5s put out 4100 lumens and the 36 W T8s give 3350 lumens. So instead of getting 8200 lum from 108 W I could obtain 10050 lum out of the 108 W, for the same length (3 T8s instead of 2 T5s). And a lot cheaper, too.

I know this might be unpheasible (sp?), but 4 or 5 of the T8s tubes could flower Catt aurantiaca or others needing high light? These may even touch the tubes. Or at least I could grow them on windowsills during the spring and summer and in the autumn to bring them under lights?

Thank you for all the info!
Good growing

[Paul Mc]

I can't help you with the technical perspective so much, but one person did recommend something to me that has worked wonders and saved me money.

His comment was that while lumens can be important, what is more important is the color spectrum and every plant needs a specific range. I don't understand all the technical stuff associated with this statement, but he suggested going to Home Depot and buying the Daylight bulbs as opposed to buying the specialty T bulbs for growing plants. I figured I would try out his suggestion since it would save a lot of money, and it appears to be working beautifully. My Phaius has some great flower stalks on them, my Cymbidium has lots of new growth (although no flower stalks - I think it was because I re-potted it in the summer and damaged the roots), and my other flowering plants like Hibiscus' haven't stopped blooming since I brought them inside.

Just a thought. Perhaps others can better explain why this guy said to more or less ignore lumens and pay attention to the color spectrum.

[Ray]

There is no doubt that one can grow and bloom pretty much anything under artificial light, given enough of it, which involves the combination of the total lumens put out by the lights, the distance to the plants, and the proper spectrum.

Incidentally, it is my understanding that horticultural T5 and T8 bulbs both put out about 90 lumens per watt, so you're actually getting 4860 from the T5 and 3240 from the T8, so your 108 watts will give you essentially the same output.

[bogdan]

Paul, how many tubes are you using per shelf? I use (at least for my AVs and streps) a combination of Cool White and Warm White right now, they put out more light than Daylight (lumen wise).

Ray, as far as I could gather from the Internet, HO T5 tubes give 4100 for the 54 W ones. This is the site

Tub Neon T5 Osram Lumilux 865 HO Petshop online Nevertebrate.ro . I hope it's OK posting sites, if not please excuse me. So that means 76 lum/W for T5 and 93 lum/W for T8 tubes (I'm just reading the package for my cool and warm white tubes, non-horticultural).

The question is, how many of them for proper growth and bloom?

Thank you!

[Paul Mc]

In regards to posting lights, as long as it relevant I don't believe you will be in trouble. It's spamming that's not good.

I don't have a "shelf" system set up. I have light fixtures hanging from the beams in my basement. There are 4 2bulb fixtures total, so 8 bulbs combined. They are all within 3 to 4 feet of each other so there are areas where there is a bit more shade (for my ferns and such) and areas where there is a lot higher light (for certain orchids and tropical plants). I use benches to help many of the smaller plants that need more light to get closer to the light, but they are still about 4 feet away or so.

I'm not familiar with Cool White and Warm White.

Like I said, it was what someone had suggested to me so I thought I would try it. I must say, even my Papyrus has made it this year which it has never done in the past so something must be going right down there, lol...

[garyb]

I have a number of difference species of orchids under lights. I started out with regular T8 shop lights, but because I have multi-level shelves and am concerned about water on the fixtures, have been moving to T5's with waterproof end-caps driven (over-driven) by ICECAP Aquarium Ballasts. It's more expensive, but I worry less about water on the fixtures and the light is great.

I agree with Ray that the T8's and T5's are around 90 Lumens/watts. The ICECAP ballasts drive the T5 tubes at 82 Watts each.

If you have a 2 foot wide shelf, I'd start with 4 tubes and adjust the distance from the plants to get the growth, leaf color, etc that you want.

[bogdan]

Your setups sound great!
I might try with 3 tubes first, as my shelves are 16" wide and maybe reconsider after I see how the plants react.

Thank you all for this wealth of information!