Andrew,
I am not an expert on indoor plant lighting, but the lights I used to use for my indoor Tropical water lily pond and the plants that got set around it were from the aquarium store.

I used 4 ft tubes in regular ballasts (shop fixtures). I had a bank of 3 ballasts and in each I had a Flora Glow and a Coral Life 10,000K reflectorized bulb. I researched it, and that combination in the same fixture emitted the broadest spectrum of light (both red and blue spectrums)that plants like for both growth and blooms.

The reason I chose the 10,000K Coral Life was that my husband was running a 135 gallon saltwater aquarium with hard and soft corals, and he used a combination hood with 2 heavy duty metal halides combined with the VHO lights that mimic sunlight at noon and penetrate the water to a certain depth to help the corals grow. I wanted something that penetrated the water, but not a VHO. The 10,000K CL does that.

I used to run these lights 16 hours a day with no damage to plants. They were on an overhead suspension set up made of PVC pipes and hung 2 ft above the surface of the water. I hung orchids around the periphery and they did fine.

I think that there is a forum on Gweb dedicated to growing under lights...maybe they could give you a better answer.

I'm not much of a hoya expert - I have one small one I grew from cuttings salvaged from my job - but I have been growing under lights on and off most of my life.

The metal racks work great - they are strong and easy to hang the lights from. You will probably need two shop lights per shelf, for a total of four tubes, especially if you are not supplementing with window light.

I personally have had lousy luck with cheap shop lights from the home store. I don't think they are designed to be run 16 hours a day in the heat and humidity of my grow room. If you buy them, you may need to budget to replace them freqently, some as soon as three months, some may last a year or two or three. I recently bought a high output T5 system from eBay - we'll see how long it holds up (I hope for a while because it wasn't cheap!)

The Growing under Lights forum has lots of good info.

Thank you two for your help. I didn't even realize there was a "growing under lights" forum. I must have missed it when looking around, there's just too many of them available here :)

I'll research the actual lights in that forum, but while I've already made a mess here, I'll inquire about the HOYAS needs in particular.

I'll be keeping them under the lights for about 6 months and am really interested in new growth vs. flowering at this time. Most of my plants are still very small cuttings. It's my understanding that the 'cool' (mostly blue, higher K) bulbs are needed for leafy growth.

I guess my main concern is this: Most of my hoyas not fond of direct, bright sun but are they able to be grown under a direct, bright, sun replica, ie. lights?

Thanks again for your help.

I have no experience w/ growing anything under lights, but I do have a friend who successfully grows & frequently blooms his H nummularioides under lights. I belive he keeps them very close to the lights (just a few inches away, like maybe 3-4" away) & tends to keep it on the moist side too. HTH

Yes, the grow lights are different. Even though they have some of the same wavelengths/spectrums of light as natural light, its almost impossible to equate anything other than metal halides or VHO's with something approaching real sunlight. The normal strength grow lights and flourescents just can't pack the same photon punch as sunlight, even weak, screened or dappled light, which is why you need to put the bulbs so close to the plants. The Coral Life bulbs come in reflectorized and non-reflectorized to send down as much light as you want, but even those never burned anything I had.
I have a 50 gallon terrarium that I was using metal halides in, and they were so powerful I had to make a "light" are and a "dark" area inside by using just one bulb instead of 2. The overshine from that one bulb was bright enough to kill the Dendrobium lodegessii cuttings I put in there with too much heat, but I have an Angraecum distichum that loved it and bloomed its head off and added 2 new leads.
I took the metal halides off though and got regular aquarium hoods with flourescents, because with the halides, and theym generating HEAT that flourescents don't, and I had to elevate the hood 6" on blocks over the terrarium, so the humidity was poor. It didn't matter for a while, but now I am thinking of getting into dendrobates (poison dart frogs) and they need it humid and cooler, and the system needs to be CLOSED so they can't escape.

If you are at all able, you could put your plants outdoors for the summer in dappled light in NC and they would probably like that very much.

Where in Florida were you living?

bihai,
I was in central FL. Orlando.

The hoyas will go outside this spring (they're going outside during the days now), summer, and fall (until it get's too cold at night). I'm just planning ahead for this coming cold season.

The past few months I've had my hoyas all inside however my collection is slowly growing and I'm running out of room in front of my allotted "hoya" window (my wife hasn't taken an interest in my hobby yet).

I'd like to create a 2 or 3 tier rack and am considering the use of HO T5 bulbs. This rack will get supplemental lighting from a window. I didn't get as much growth out of my plants this winter in NC as I had been getting in FL so I'd like to give the plants a pick-me-up this coming winter.

Are you anywhere near Plant Delights nursery? I have a friend here (I am in Gainesville, she is in Newberry) who likes to drive up to NC for their open house days and buy plants. She says their grounds are pretty fantastic.

Unfortunately no, I'm a few hours away.

Plant Delights Nursery, Inc.
9241 Sauls Road
Raleigh, NC 27603

I may go browse the local hydroponics shops to ask questions about grow lights. I wonder if they'll know what a hoya is? LOL

While I agree nothing beats the real thing, I have 2 flourescent light fixtures under my kitchen island cabinetry, and my plants seem pretty happy under them. Both fixtures came with warm bulbs, but when they burn out I will replace them with one warm and one cool, which I have heard is better.

When I first thought of installing them, I got alot of great advice at the indoor lighting forum, there are some very helpful people there, all you have to do is ask a question.