Light discussion

[Daemos]

Not sure if this is the right place to post but here comes.

Wherever I go and read about orchids everyone has a different opinion about light wheter artificial or sunlight.

Some say that phals burn if exposed and to direct light and some state that they grow just as fine. I read that Vanda coerulea species don't need direct light and do fine with just a little and that other species need alot. I can't find any proper scientific data on daylenghts concerning these plants. How much light a day does these plants expect. i read 12 hours of direct light a day but some sources state 6 or even 3. Im getting confused here and doing something stupid may just kill my plant for good. And in the case of articial light. How far are the plants away from that lightsource. In the case of real sunlight. What would be the best window direction concerning vanda with loads of coerulea in them. What is the least amount of sunlight these plants can take and what is the max in daylight hours?
Does anyone have foto's of light setups concerning vanda coerulea species (sansai blue or even mikassa). All I need right now is getting the light right and somehow it doesn't work out well yet
How can I also see that a vandaceous specie is reacting properly on the light given to it (except for the blooming offcourse). What is worser? Too much light or too little. What will happen with too little and what if too much (leaf color, roots, growing, dropping leaves).

If I hang a vanda coerulea specie in front of a northwest window in summer will I have enough light for flowering it.

Lots of annoying questions srry for that. but concerning this plant I am a total beginner

[Ross]

My recommendation is to read about the lands where the parent plants would be found (the crosses aren't normally found in nature) then read up on the day length, amount of sun, rest periods (if any), rainy season vs dry season, etc. This should provide your answer. Then, as I have said befor, if one is growing under only artificial light or mostly artificial light, then realize the amount of light being provided is a constant level compared to the increasing light/decreasing light in nature or a greenhouse where sun rises, reaches it's peak, then sets. Light intensity changes. This is why one can bloom certain spp under lights that you would think too dim. Many here grow and bloom Cats for instance under t12 shop lights. How can this be if they provide so little light? It's because of the length of "day" that is being provided without clouds, storms, etc. to spoil the light. Hope this helps a little.

By the way, a good place to read up on natural conditions is Internet Orchid Species Photo Encyclopedia Just look up the Genus in the alphabetical listing.

[calvin_orchidL]

Hello! no worries - I've been (and sometimes still am) in the same situation as you. Light is really important and it's also confusing. You may want to go to the light related side of the forum (http://www.orchidboard.com/community...-under-lights/) to get some good information, but in general there are several things you should be aware of, concerning light.

Intensity, color rendering, and color temperature (someone please correct me if I'm wrong). Artificial light will vary in all these things, whereas sunlight pretty much has a really good color rendering and temperature, so the main thing you need to worry about is intensity.

As for the amount of light required for your plants, I find the most important thing is to try different situations out. Typically people grow with 12 hours in winter and 16-18 hours in the summer. Too much light will result in yellow leaves...red tinged leaves = max light (although I think some people also get red leaves when they change the light levels from low to high, even though the 'high' is not the highest the plant can tolerate). I've found also that I get a bit of leaf drop when there's a lot of light..maybe the plant thinks - hey I don't need all these leaves anymore (this is mainly for monopodial orchids).

Too little light and you'll see dark green leaves...also some people say that you will see longer, strappier leaves but I think that's a little controversial.

Try different things but don't move the plant around too much before you've had a chance to see how it responds...leave it for a few months in a location you think is right. If it shows you signs that it's unhappy, try something else. That's what makes orchid growing challenging and fun

[Daemos]

Thank you for the quick response. I am seeing this red tint a little bit and the plant is dropping a lower leaf. Guess Im overlighting. I am still a little bit confused though. Te artificial light boost is very powerfull. So powerfull that all the other plants are growing towards the lamp instead of the sun

With the help of the orchid database I managed to figure out the following. Vanda sansai blue is a crossing between euanthe/vanda sanderiana and vanda coerulea. Both species require huge amounts of light (3000-4000 fc) but with shade so not too direct. Stated for euanthe sanderiana "LIGHT: 3000-4000 fc. Plants require very bright light, but direct sunlight
should be avoided. Strong air movement should be provided at all times." and for coerulea "season in the winter with daylong sun."

guess its going to be trial and error :S What I still not get is the fact that there has to be like 3000 fc in light but not direct.

Will more light also boost root growth like it does with other plants?

[Ross]

Originally Posted by Daemos

Thank you for the quick response. I am seeing this red tint a little bit and the plant is dropping a lower leaf. Guess Im overlighting. I am still a little bit confused though. Te artificial light boost is very powerfull. So powerfull that all the other plants are growing towards the lamp instead of the sun

With the help of the orchid database I managed to figure out the following. Vanda sansai blue is a crossing between euanthe/vanda sanderiana and vanda coerulea. Both species require huge amounts of light (3000-4000 fc) but with shade so not too direct. Stated for euanthe sanderiana "LIGHT: 3000-4000 fc. Plants require very bright light, but direct sunlight
should be avoided. Strong air movement should be provided at all times." and for coerulea "season in the winter with daylong sun."

guess its going to be trial and error :S What I still not get is the fact that there has to be like 3000 fc in light but not direct.

Will more light also boost root growth like it does with other plants?

I don't think more light boosts root growth. That comes from proper culture like water and fertilizer. I think you are worrying too much about the 3000 FC. I really doubt you are giving it that from the CF bulb. The leaf drop is probably not from the light but from either shock or just passing an unnedded leaf. Did the plant recently grow a new leaf at the top?

I recently moved a Tolumnia spp to the top shelf of my tank under t5 lights at 1800 FCs. Tolumnias regularly take 2800-3800 FCs as they grow on twigs at the top of trees in the Caribbean. This one had proper pale green leaves while in a south window. In the tank under "less light" the leaves took on a reddish tinge. It was getting more light energy, not less. Watch for pale green leaves or a tinge of red on leaf margins and you'll know you are giving it enough light.

[calvin_orchidL]

Yeah - Ross recently 'enlightened' me (sorry :P) to the fact that while in nature the light intensity varies, with artificial lighting, the constant light means that you can probably do with fewer FCs stretched over the course of the day. This was incredibly helpful, and also a relief (trying to get 3000fc on a CFL was nearly impossible lol)

[Daemos]

Lol Im finaly starting to get the sense of all this now I think.
The leaves are beginning to get a reddish purple tinge so I moved the light somewhat further away. I also found out the daylenghts in thailand and they are about 12 hours a day.
The plant did not recently make a new leaf but is growing a small one in the top and it seems its getting bigger.

So just to sum up and get things straight this is what I understand from you guys so far:

-It doesn't matter how much cf's you count, its all about the energy within the light (active UV)
-Growing roots has nothing to do with light but more like feeding and proper wattering
-Seeing a bright light color or a purple tinge on your leafs means you are giving the plant exactly what it needs
-you need far less light if you go artificial since daylight loses strenght during the morning and at the end of the day and thus compensates for the lower amount of active light your bulb is giving you.
-Lower leaves dropping isn't as bad as many beginners may think it is natural for these species as they grow newer leaves on top

Guess Ill have to wait now and see what happens right?
Here is a photo of the purple tinge btw so you guys can see what I am seeing.

[Ross]

You got it! Your plant looks fine to me (keep in mind I don't grow Vandas, but grow lots of hi-light orchids). That's not too much purple color (in my mind). Probably just about right. Don't worry right now about one leaf dropping off.

[ipv6ready]

Quick question, my nobile new growth is turning bright lime yellow. But my old canes have dar green leaves. They are 3 inches from two 23 watt cfl could this be because of too much light?
Sorry for hijacking the thread, but I thought it was relevant here, rather then starting a new thread.

[Magnus A]

A agree with Ross that your plant looks healthy and fine! But I have one comment on light and root growth. More light leads to higher respiration that leads to loss of water. This mean that under high light the plant needs more water than under dim light. To compensate when moved from low to high light the plant can (not will) produce more roots.


ipv6ready:
no not for sure. even older leaf usually turns light green under enough light (for cattleya´s at least) . One explenation could be fast growth due to "to good culture". One vanda grower I talked to said that fertilizing to much yielded to fast growth and a "weak" leaf. Less fertilizer shorter "growth zone" and stronger plant.

/Magnus