Mostly, it depends on how close you put the plants to the tubes as to whether or not they get enough light. I grow strong-light orchids, like Sophronitis and Catts, under cheap 48" shop lights (about $10) with T12s by letting the leaves almost touch the tubes (1/2" or so), while lower-light plants like Paphs and Phals sit about 4-8" below. It's the distance which makes the real difference.

Thanks for the input. Does the number of fluorescent lights affect how close you put the plants to the bulbs?

Also, do you use the same distance for T5s as T8s and T12s?

Way back in the past when I set the lights up, I measured the light output at various distances, up and down and to the side using an old light meter to get a general idea of placement. I use two shop lights, end to end, giving me 8' of double T12 tubes rather than a wide bank of four. The main plants are right under the pair of tubes and raised up when strong light is necessary. I don't grow a lot of plants under lights so it is mostly a single or double row directly under them and shade lovers like Pleurothallids to the side.

I only use the brightest rated T12s. But you can check the lumens on the other types; if the output is similar, then it would work pretty much the same. But the best check would be with a light meter. I am using the same little GE one I used for photos back in the old days when cameras didn't have them built in. You'd be surprised how many older relatives and friends have light meters tucked away forgotten in a drawer.

With fluorescent tubes, you need to change them regularly since they begin to dim after a few months use. I change mine every six months (use the old bulbs in other fixtures since they still have a lot of life in them). It's a minor expense with T12s.

I'm on my first cup of coffee. Am I making sense?

Hopefully Bob or Calvin will weigh in on the T5s. I do know if they are the High Output T5s, they are much brighter but also run much hotter. This means the plants must be lower but the intensity means a wider range of types can be grown.

Brooke

Congrats on that Phal blooming for the 2nd time! You're doing a bunch of things right in the culture department for that to happen, in addition to the light.

Two 48" T8s will provide more than enough light for 3 Phals - as others have said, depending on distance from the tubes. And, if you can't stop at 3, or fall in love with, say, Dendrobiums... well, you have room for quite a few more orchids. :)

One question is - do you have natural light reaching the Phal? If so, what direction is it from? And is it obstructed by trees, other buildings, etc. all or part of the year?

Also, if you've got natural light, how close to the window or other source of light are your Phal and the T8s?

This info may help suggest options.

WhiteCat8

I agree with the rest, the 48" T8 fixture can handle three phals if within 4"-8". Also, the light is usually much brighter at the center of the tubes as oppossed to the ends, so try and keep them centered as much as possible to receive maximum light.
In my experience, with phals the problem sometimes becomes what to do once the spike(s) get taller than the plant. Then a bright eastern or slightly shaded western window may help or start raising the light and put the shorter plants on pots to keep them close to the lights.

Good growing,

Bob

Wow, thank you all for all the input!

cjwatson and highjack, I had no idea there were different kinds of the same type of bulb with different lumens... that there are different kinds of T8s or T12s. That's a revelation for me.

whitecat8, unfortunately I'm limited to a north-facing window with a huge tree in front of it. :/ My plant is about a foot away from the window though.

westoh, yes, I am having that problem! I was raising the light for a while, but now I have it staked at a slight angle so the leaves can still be almost underneath the bulbs.

Do you all put your plants parallel with the bulbs so they're getting the most light out of them? Also am I understanding correctly that the benefit of brighter bulbs would be that the plants don't have to be as close?

I have a feeling this hobby will get addicting very fast!! :D

Yes, try to keep as much of the plant as possible under the lights. I use 4 bulb fixtures, so I can go in either direction. As far as the staking, remember the spike will always try to grow towards light, so this is why it gets tough when the spike is 12" or more taller than the plant and you are trying to grow under lights.

As far as more lumens/light and further away: Using standard flouros, always try to keep phals within 4"-8" inches. As far as flouros, more is better as it's hard to give/get too much light when using flouros.

You should try to mix a soft/cool and warm colored bulb also, more closely imitates the natural sunlight and helps in both growing and flowering. I use T12's and CFLS, so I'm not sure of the options for T8's as far as colors.

The T8's lumens are pretty close to what I get from my more energy sucking T12's. When looking at T12 bulbs at those big box stores, I see where they generally come in lumens anywhere from 2200 - 3300, as CJ said, always try to get the most lumens for the buck and mix the colors, lumens are your phals friend.

Hope this helps,

Bob

I asked my insignificant other, a retired elec engineer, how much electricity a standard two-tube T12 48" shoplight uses in total, and he said the same juice as a single 100w light bulb. That is cheap. Very cheap. (Do you realize how much the gasoline costs for that hobby bass boat or how much the greens fees are for that avid hobbyist golfer?) Orchid growing is really quite cheap by comparison.

For the 'chids under lights, I use the cool white 3200 lumens, same as I use in the garage and in the regular GH light fixtures. In my house I use the warm whites; can't stand the brightness and glare of the cool whites. At one time, I used some of the broader color spectrum tubes for the plant shelf, but found no difference in growth or blooming.

ORCHID GROWING IS REALLY QUITE CHEAP BY COMPARISON

Until you build a big g/h to handle the addiction :>)

Brooke

CJ,

I was assuming that the OP didn't have much natural light, thus the suggestion for a mix of colors.

Let's see, I burn 12 T12's 16 hrs/day, 4 65Watt CFLs 16 hrs/day, 1 85Watt CFL 16 hrs/day and now a 250Watt HPS for 12 hours a day. I'm thinking I'm paying at least $30-$40 a month in just those lights. Add the current plants value (@$1K), the >$3K for the ones I've killed and the @$1.5K on the light set-ups, the fert, plus the pots, the mounts, the clips, Orchids Magazine, etc... sometimes I wish I still golfed instead :-)

Bob