Hi tuddie - there is a vivararium formum on the Garden Web and they know all about lighting, humidity, fans, etc. for enclosures. Some even have small critters in their set ups. They should be able to help you with your questions.

Brooke

Yes, go ask the experts about ventilation, humidity (with wood?), all that stuff.

I can give you an idea of what lights you might need. Hoya might be tricky. As you say they would probably survive with no extra light but if you want flowers you will have to get some fairly intense lights. Looks as if you are lighting a two foot square growing area, so you will be looking for something like 6,000 lumens.

Possibly 2x55W twin-tube compact fluorescents would work for you. They are 22" long and produce about 4,200 lumens each, you'll need a separate ballast to drive them. You can also get 55W spiral compact fluorescents that are self-ballasted and will screw into a standard lamp holder but only give 3,500 lumens each, also not such an even light distribution. With a two-bulb setup, maybe you could just run one for part of the time and two for the flowering season.

Thank you shrubs that is a good idea about the two-bulb set up. However, what I was thinking from what I read was MH bulb for foliage and High Pressure Sodium for the blooms. What is the difference in using these and using fluorescents? I thought fluorescent did not produce the proper spectrum?? tuddie

I thought fluorescent did not produce the proper spectrum??

That's what the MH/HPS sellers would like you to believe ;)

The space you have is too small for HID bulbs to be necessary or useful. HID is relatively inefficient at the power levels you would want (maximum 100W total). To be fair, a single metal halide bulb would be about as efficient as using two spiral compact fluorescents (although less efficient than the flat two or four tube compact fluorescents), but they are more expensive, have atrocious lumen depreciation and are more expensive. Nor should you need the extremely high light intensity you can get with HID.

Your plants will flower when they are mature enough and they have sufficient light. Plants do not need a specific spectrum to produce flowers or fruit although a measurable effect has been shown. The "red=flowers, blue=growth" dogma is simplistic mis-representation by lighting sellers. HPS lamps are preferable because of their extremely high light output and efficiency but in some plants they can produce etiolation. Once the major growth phase is over, etiolation ceases to be an issue and the higher HPS light output is preferable. Some plants have showen some effect on flowering and fruit set from spectrum, I don't know if there is any effect at all on Hoyas. I have flowered a wide range of plants under standard triphosphor fluorescents. You can always switch in a warm white fluorescent as the second bulb for flowering, if you find that more red is beneficial for flowering.

Metal halide lamps produce more compact growth in most plants (although not actually more growth) and so are used during initial growth phases when etiolation needs to be avoided. Metal halide lamps have also been preferred for the growth phases of certain plants containing alkaloids because of their higher blue and ultra-violet output which encourages alkaloid production.

Wouldn't extreme heat from either HPS or HID lights be an issue in such a small enclosure?

Brooke

An HID lamp of the same power as a fluorescent lamp (in this case around 100W) produces the same amount of heat. The perception of extreme heat from HID lamps is partly because they are usually very high power, and partly because HID bulbs are (much) smaller than fluorescent tubes and so they operate at a (much) higher bulb temperature. They also radiate more infra-red than a fluorescent and are usually placed further away from the plants. Heat and ventilation within an enclosed structure are obviously important, but planned correctly the lights can keep things pleasantly warm rather than cooking everything.

I didn't know they made HID that small. We have two 1000 watts in a room and the temps could get quite high even with fans running 24/7.

Brooke

Shrubs..I apologize for my tardiness in thanking you for so much good information. I hope you will help me out even further, if you don't mind.
With the information you provided me, can I place the lighting overhead in the glass area? I have taken time and considered all things and the overhead lighting using the cavity which once was the 'freezer' of the piece is the best place for the lighting fixtures to go. I took acurate measurements fo the cavity at 20" deep X 17" wide. I did look online at kits that have the compact fluorescent in a reflector and the ballast is built in. They are the right size for the overhead, but I would like to have your input as to how to do the overhead properly. Best Regards, tuddie