Light project for phals

[fongwee]

Dear all,

I am intending to build a rack for indoor use. It will have 3 layers. 1 for catts, 1 for phals and 1 for tillandsia. Would be planning to do it under lights.

Since the shelves will not be adjustable (DIY), I would need a rough idea the lighting requirements to decide on the shelves dimensions.

I have found out the following information.
Phals: 1000-1500 FC
Catts: ??? (?3000 FC)
Tillandsia: 4000-7000 FC

The maximum height of the rack is 80". The bulbs must be energy efficient and long-lasting. Are MH bulbs a good idea and the wattages that I should use for the different layers?

Does anyone have a good link on wiring the MH bulbs?

A lot of things to consider. Thank you all for your time.

Cheers

[SheilaJ]

For the phals, you can do a nice job on a 18" x 48" shelf using 4 four-foot long fluorescent tubes. Get T8, or if the budget allows, T5's. High output T5's throw off a lot of light, almost too much for the phals. But they are easier to deal with than the halides.

What size shelves are you thinking about? Do you like to build stuff, because you can do a nice job with a chrome shelving rack with a lot less work (that was my only option, since our house is handyman- impaired!).

I'm still trying to master catts, actually just minicatts, can't help you there. Those tillandsias are asking for one heckuva lotta light, that's going to be a challenge.

[Grandma M]

If you would like to start with a pre-build rack, the big box stores sell a great 48" rack. I use one and I could adjust the shelves to whatever distance between which I needed. You can hang light units on them. Just make sure water will not drip on down to the lights below. I grow my plants in 22 X 48 inch trays so there is no chance of that happening.

There are a lot of growers on the forum who use these.

[fongwee]

I am intending to build an aluminium shelf. I stay in tropical singapore and the chrome stuff is unable to last for very long before it shows rusting. Also, this chrome wire shelves are pretty expensive in Singapore.
Thanks for the advice on the fluorescent tubes. Was thinking about it and it is definitely easier to wire than MH lights. For the tubes, how many do you put for each layer?

[Daemos]

If you really need a huge amount of light for cheap you can also try CFL growlamps. Youll get something like 3500 fc per CFL tube.

If you have oxidation problems on aluminium or chrome you can use transparent acryl based paint. The surface has to be extremely clean before applying and youll need the spraycan version. That way you can also protect your reflectors from oxidation.

Also bear in mind that if chrome oxidises in your area copper will oxidise as well. You have to keep that in mind when you start planning with your wiring.

I think that a total of 200Watt light will get you enough light for about 5 phalanopsis. That is though a very rough guess based on foto's I observed.

[NickEngler]

I'm assuming by "MH bulbs" you mean Mercury Hallide. But from what you say about the shelves you are building they would provide too much light and heat for them to be useful. The source would just be too close to the light.

I recently started using high-output flourescents from Gardeners.com (other places sell similar lights) and have succesfully flowered several mini-catts, as well as several other species and varieties that haven't bloomed under the regular T-12 grow lights. I had to move my Miltoniospis to the ends of the bulbs becasue they provided too muc light. My phals were already at one end of the shelf and the increased lighting doesn't seem to have latered their appearance.

I don't have all the specs on the bulbs anymore but they are a broad spectrum grow light type bulb, T-8s (as opposed to T-12s), 32 watts and four feet in length. Supposedly they last at least 10,000 hours. Depending on the plants the bulbs are 2-10 inches from the plant -- some of the tips of the leaves sunburn but the plant is basically OK. I have also seen some even higher intensity T-5 bulbs (I think they were 52 watts) that you might check out.

I think something like this might be better for you than the High Intensity lights of either mercury vapor or high pressure sodium. In general they are lower wattage, almost always four feet long and are fairly cool so you don't have to deal with getting rid of the heat from the higher wattage bulbs.

From my accumulation of info over the last few years, depending on breeding background, Cattleyas need between 2000 and 3500 footcandles. Laelias are about the same but Brassavolas may require up to 4000 or more. Some of the Phal species may require more light than most of the large pink and white hybrids available. I have three Tillandsias and one of them is very happy in my east kitchen window, the other two are surviving there, and that is about what I know about them.

I found a very good article on the net by Tony Whitaker of Kingswood Orchids. Unfortunately I saved the article but not the link. It gave a lot of the basics, and was fairly detailed but not so overly technical I couldn't understand it. You might try to Google it. I know I found lots of info, some useful but some not, when I was looking.

[fongwee]

Thanks a lot for all the information. Think I would go ahead with the T5 lights since they are easier to wire.

Can I check how may tubes do you put?

[SheilaJ]

The T5 high output are 55 watts for a 4 foot tube; regular T8's are only 32 watts per tube. The difference in the amount of light they give off is enormous. I haven't tried my phals under the T5's yet, but I'm guessing I'll have to watch carefully for sunburn and keep them near the ends of the tubes or farther down from the bulbs. The higher light plants would really appreciate the T5's. Plus they are skinnier, so you can put them closer together if you want.

If you go with the T5's, for phals, I'm guessing 2 tubes for each foot width of shelf. For the other plants, 3 to 4 tubes per each foot width of shelf.

[Ocelaris]

One thing to remember when comparing T5s to T8s, is that the standard T5 we talk about is actually a HO (High Output) as for as NO (Normal Output) the T5 and T8 are basically the same efficiency and lumen output. This is not to denegrate on the T5, which have become the standard lights for growing under, and vastly better than fluorescents in the past.

Fluorescents are easier to work with (come pre built) and relatively cheap, hence their propensity in our trade. However they can not deliver the required high light levels required for some of the larger orchids which may be 2-4 feet tall.

Because when you start housing 2-4 feet tall plants most people use natural light, there is a big gap in the knowledge of High Intensity Discharge lighting. HIDs incorporate any of the arc tube lamps such as Mercury Vapor, High Pressure Sodium (HPS), Low Pressure Sodium (SOX), or Metal Halide. Mercury vapor are no longer used in any new setup, as they are relatively inefficient and their spectrum is poor compared with newer bulbs. LPS (SOX) is also not used because of it's monochromatic spectrum. HPS with color corrected bulbs may be the most efficient bulb commonly used, although they are still obnoxiously "warm" to look at. Metal halides make up the majority of "pleasant" HID lighting.

While it is true there is more heat in the larger Metal Halide bulbs, they also are often more efficient than fluorescent tubes as well. So the pretension that big Metal Halide lamps are "hotter" than fluorescents is false, they are actually cooler (because of their higher efficiency) per bulb, but the heat is concentrated.

Regardless of whether you choose to use Metal Halide or Fluorescents, if you are making an enclosed growing area, you will want to seperate the bulbs from the growing area. Or if it is the same growing area, you will want to make a shield to keep the heat from the lamps from the plants, fans are recommended. Just because you can get away with not using a heat shield with fluorescents, does not mean it is a good idea, all bulbs are hot and should be vented away. T-5s (the standard HO variety) however need to have an ambient temperature of 95*C.

You will be hard pressed to get 4000 fc out of most artificial lighting that doesn't burn the plant leaves from heat... 7000 is incredibly bright and at least full sun... 2,000-5,000 is what Vandas reccomend and they take 25% shade cloth from full sun... My Vandas turn purple (too much sun) at 2000 fc.

Comparing daylight to artificial light you can basically cut those daylight measurements in half because the total radiation of a daytime light may only be half on average, where as the radiation from a bulb is 100% all the time (unless you have clouds in your house!). so a 5000 fc plant in day light may only need 2500 in artificial light... this is a gross simplification, but read that 4000-7000 fc number as "all the light you can spare and then some".

I'm putting 2x250w Metal Halides at 4 feet tall, and I expect to have about 2000 fc at around 1.5 feet away from the bulb where the plants will start... But time will tell whether that calculation is accurate.