a link to desired foot-candles for different chids?

[let_it_grow]

I grow almost exclusively under lights and I was wondering if anyone knows of a reliable link i can go to to figure out how many foot-candles each plant needs. What fc range should be offered to high light chids, med light and low light?

[Ross]

My best recommend right now is OrchidWiz. While a bit pricey, I find it worth every penny. Has FCs range for thousands (or more) orchids and hybrids as well as all sorts of other stuff worth reading. Just a thought.

[let_it_grow]

Thanks Ross... I was looking for something in the free-ish price range. Any ideas? How many FC is considered lots?

[Ross]

OK, since you asked, I'll post a couple check points:

Sun at equator at noon on clear sky day - probably in the 5-6000 FC range.

Full sun at 45 degrees north latitude in June on clear sky day (cloudless sky) - probably in the 3500-4000 FC range

Orchids needing full sun are described that way based on a few hours mid day at the full-sun range (usually tropics or equator). At 45 degrees latitude, for instance, full sun in mid summer will be tolerated by most Brassavolas, Sophronitis, Laelias (especially rupiculous types), Brassias, Potinara, etc. for most of the day.

The "supposedly" shade loving orchids like Phals, Paphs, Phrags, etc. will do well at 45 degrees latitude in full sun (especially if behind a window screen) such as a south-facing window.

A caveat for my above recommendations:

In nature, light starts dim in the morning, increases over the day to a peak somewhere between noon and 3PM then starts declining until sundown. The light graph would be a "bell-shaped" curve. If you grow under lights with a timer (I think I remember you said you did) then the output is constant. I've challenged folks to take light meter measurements outside in, say June when days are longest and skies clearest, and average them over the day length. This will be the average for your latitude. Even in south Florida, the same factors apply and the day length is shorter. Then compare that to what you are able to supply.

Most of us light growers, use t5 florescents or HID or MH hot lights. They have a constant measurable light output. I will say without doubt that 2000-2500 foot candles for 12 hours will be more light than a natural situation where full sun approaches 4000 foot candles but diminishes over the day to zero. Don't forget, when it's dark outside this time of year, you might still register 2000 or more foot candles.

Sorry this is so long. In short, I am growing a mounted Brassavola (said to desire full sun or very bright light - like 3500-4500 foot-candles) in a tank under 48" t5 florescents set approx 8" above the plant. The leaves are reddish and when I first placed the plant there after obtaining it from a grower with greenhouse and full sun, it fully went maroon - all the leaves - like it was getting sunburned. Now it has settled in and the leaf margins are purple, but the newer growths are nice and light green. I supply 1800-2000 FCs for 12-16 hours.

Artificial lighting is not so simple that one can make a list of foot candles. I guess that's my point. Once you see the intended brightness published, you should be able to adapt that to your growing conditions. This is probably confusing and not much help, but best I can do without very specific questions.

Here is list of plants I grow in my tank under t5 lights, in a basement where artificial lighting is sole source:

"high light" (right under the lights at approx 8" 1800-2000 FCs) Dendrobium aberrans, Brassavola nodosa, Dendrobium moniliforme (2 types) and Angraecum didieri.

"Medium light" (about 12-14" below lights 1200-1800 FCs) Neofinetia falcata, most of my Angraecoides, Pleurothallis tribuloides, Haraella, Cischweinfia, Tuberolabium, etc.

"Low Light" (at bottom of tank, approx 24-30" below lights 600-800 FCs) Jewell Orchids, a Bulbo, Dracula, Java Moss, Sarcochilus fitzgeraldii, etc.

Hope this helps.

[let_it_grow]

Awesome!!! Thanks so much Ross. I just switched to a new setup with the plants on a shelf and the lights mounted on the bottom of the shelf above it (i'm using horizontal space cause I have long since run out of vertical space). Since each shelf has its own light there is much less space between the plants and the bulbs. I'm pretty sure i need to use less light now. Is the reddish colour a bad thing? I noticed it on my Dens and my Phals new leaf is showing much more red than the others. The Phal does have a dark purple flower but the other leaves have 1/3 the reddish/purple than the newest leaf. Is this a sign of too much light?

[let_it_grow]

Oh yeah .. I'm using a timer thats on 14hrs a day .. timers make things sooooo easy, I couldnt live without them

[Ross]

The Phal might be just a tad reddish from your description, but I don't think I'd worry as long as it appears healthy and blooms. 14 hours might be a bit long this time of year. Mine is set for 11.5 hours right now.

[let_it_grow]

good to know. I think i threw my chids outta whack with the lighting cause I just noticed a bunch of them actively growing. A Phal my Cyms, my Paph is either flowering or has some new growth, my Dens and an Onc. They all have new growth... did i confuse them?

[nhman]

I have had catts get sunburned during my initial "experiments" under T5 lights.
I have found that extensive use of light meters, daily observation and some unfortunately overly toasted plants were the result, but most have now settled in to a good life and growth habits. Some still bear the marks of too much light with dark spotted leaves.
As in other posts, get a good light meter, get your plants into "range" and then just observe what they are doing - look and listen and they will tell you what they desire!!

[let_it_grow]

LOL I just noticed that I mixed up part of my explanation of my setup, I meant to say that I'm using VERTICAL space cause I have run out of horizontal space. I had to correct myself cause it made no sense otherwise