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red leaves

Posted by ttkidd Toronto ON (My Page) on
Thu, Jan 29, 09 at 12:39

Because I wasn't getting any blooms, about three weeks ago I moved my B. nodosa and B. Little Stars from the end of my t5 light fixture to the center of the fixture, tips of the leaves about 3 inches from the bulbs. Within days, anything facing the light turned red. I understand this is because of the increased light, but it was also my understanding that the red would eventually fade. This has not happened yet. If anything the red continues to get deeper, to the point where the light facing surface of some of the leaves don't look even remotely green anymore. Texture of the leaves remains the same...there is no wrinkling, yellowing, or browning of tips, and the roots still appear white (green tips) and healthy. The parts of the leaves not directly exposed to the light remain a nice mid-light green.

When if ever can I expect the red to fade? Should I move the plants farther from the light? Is there anything else that should be looking at?

Thanks

Tyler


Follow-Up Postings:

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RE: red leaves

The red would eventually fade when the plant is take away from too much light, not while it is still experiencing it. Your plants are trying to tell you that they are getting a bit too much. You might consider lowering them from the bulbs a bit or moving them (an inch or so at a time) away from the center of the fixture.


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RE: red leaves

The red should remain as long as the high light conditions are maintained.

Moving them or not is your own decision. I've had B.nodods and Little Stars outside in summer in very high light and they stayed red. No harm done, and it's my belief they bloom more generously in higher light. They originate in Mexico, a long way south from Canada.

Many catts kept in high enough light to bloom well won't have nice leaves of any color. There's almost a leaf beauty vs flowers tradeoff.


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RE: red leaves

Hi Tyler -

I grow mostly under lights also and I actually like to see some red on my catts' leaves b/c in my mind that means they are getting plenty of light. As Mehitabel says, sometimes the foliage doesn't look all that hot. If you are worried about them, you could move them farther from the light, but for me, I'd let them be. :)


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RE: red leaves

Not sure that red on B. nodosa is just due to high light. High light plus some other factor??????.

Just looked at my in-bud B. nodosa and it has not got one red leaf and it is getting extremely high light even though it is getting some shelter from the sun in a glasshouse.

Ditto for Dendrobium speciosum in almost full sun. No red leaves.

Less red leaves on my Phal collection than in winter.

Generally extreme high light short of sunburn results in pale green coloured leaves.

Perhaps it has something to do with the type of light??????

Just surmising, i grow nothing under lights and have no idea about foot candles and stuff.


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RE: red leaves

My Little Stars is blooming now and also has the reddish leaves. I've always assumed that color to the leaves is a good thing for the reasons stated above, but here's another thought: I wonder if any new growth that develops under the higher light conditions will be green or reddish? I can understand the reaction of the older leaves turning red (kind of like human skin reacting to too much sunlight), but if a brand new leaf develops under those conditions, maybe it won't need to produce those pigments since it will already be conditioned to the higher light?

That would explain Arthur's comments about his plants. I would assume they've been grown under the higher light conditions for most of their lives.

Kevin


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RE: red leaves

Interesting. I've had a phal in a window develop a light blush to its leaves before and thought it was quite pretty, but I've never seen anything go this red, and I never thought that growing under lights could provide too much light for anything but the lowest light plants. Sounds like I should keep it where it is for the time being unless I see signs of leaf damage. Hopefully this is a good sign...looking forward to some blooms.

Thanks for the tip about the new leaves Kevin. I'll keep an eye on them until I see signs of new growth.

Tyler


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RE: red leaves

Have you felt the leaves? Are they hot? Are they warm?


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RE: red leaves

Interesting input from everyone. Not sure if the classical warm-leaf test works, since the T5s don't give out that much heat (although more than T8s and T12s...less than the sun and HIDs). Just some reference though - T5s can get very bright. My barkeria melanacaulon placed under them (originally light green) did exactly the same thing - turned purply red in a week. This was 6-8" away. Although I did realize later that this one may prefer a bit less light (and so I've moved it away...around 2' away now, and still purple), I think it's important to remember that under lights, a constant exposure amounts to a much higher level than outdoor sun exposure, which varies in intensity from dusk till dawn. IE a catt might be recommended 2500fc, but keeping a catt under 2500fc of artificial light for 12 hours straight is probably a bit too much. I've found that you can get away with less, and a longer duration.


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RE: red leaves

I have a Binosa and it hangs in the top of my green house and the leaves are red and seem to be no problem


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RE: red leaves

Don't get me wrong.....Red is generally good. Its just that non under lights orchids exposed to very high light here are not especially red.

For example, next to the Den. speciosum's is a a Schombo/Cattleya hybrid. The leaves are a horrible lemony green pitted by adversity. Not a thing of beauty but the flowers are fine. Perhaps extreme UV fades the red?


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RE: red leaves

My B. Little Stars blooms nicely under T8s with just a speckling of red in younger growths. However, I have a Doritis pulcherrima on which the maturing leaves become red even 16" from these bulbs. My understanding is that the red pigments underlay the green and when the chlorophyll is killed or repressed they show through, as with deciduous leaves in fall. I suspect my Doritis may be short some of the nutrients needed to produce or maintain chlorophyll, and that the mature leaves sacrifice nutrients to the newer growths.


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RE: red leaves

rockyfarm there are some Doritis pulcherrima that actually have a reddish/brownish look to them. Growing it 16" from T8 lights is only giving it about 200 fc's. Check it with a light meter, it is basically growing in the dark.

Brooke


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RE: red leaves

The Doritis leaves turning red are the first to yellow, shrink, then drop; some of the older lower leaves have remained green. I agree that the light level is very low, but I'm afraid to move the plant closer until I "feed it up".


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RE: red leaves

Orchid126: The leaves don't feel warm at all....at least no warmer than the growing area which in the winter doesn't go above 28C. In the summer I've seen it go as high as 32C.

A related question:

Calvin (or anyone else growing under t5s), how far do you keep your high/medium/low light plants away from the bulbs?

Thanks

Tyler


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RE: red leaves

I'm with aachenelf.

My Little Stars is in bloom and has some leaves that have red along them where they get the most exposure. I also have a Yellow Bird, which shares a parent with the Little Stars, and when I first brought it home, that spring it began to turn VERY red on the existing growths. However, the new growths adapted to the high light and ended up giving me magnificent flowers, and did not turn red.

The Little Stars seems to be doing well, with 5 bloom spike, having 2, 2, 3, 4, and 4 flowers apiece. The ones with 4 flowers are the ones emerging from the reddened leaves, so that tells me they must like the light.


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RE: red leaves

If the redness bothers you, spray the plant with magnesium sulphate (epsom salts, 1 tbsp per gallon) instead of fertilizer on the next feeding event and it as the new growths come out, they will be nice and green. The problem is a combination of bright light and nutritional deficiency. Most soluble fertilizers may not have enough magnesium. I have confirmed this many times on cattleys with same symptom. When I spray with epsom salts while a new lead is growing and showing the rdness, withing days you can notice the new growth continuing to push out and now it is a solid green.


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RE: re leaves

I was just wondering if anyone would remember that mag sulphate would remedy the red leaf bit when you posted, Ben. I don't spray--I saturate the media four times a year to suppliment my fertilizing program. Mixing epsom salts with fertilizer will bind the nitrogen so that the plant can't use it, but it won't really hurt the plant for that one time application. I prefer to use it alone.


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RE: red leaves

Any redness on a B. nodosa is good. I've seen them in the wild and those that get alot of sun are as red as red can be and were covered with flowers. You pretty much can never give to much light when using florescents. I have everything from species phals to catts and nodosa under them and they all grow and bloom fabulously. So don't worry about the red and enjoy your blooms when they come!


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RE: red leaves

A lot has changed since I started this thread back in February, and I'm wondering if I'll even need the lights anymore. I just moved into a new condo with some amaizingly bright windows and while I was setting things up I thoughtlessly placed a box of my orchids right next to them. After only four hours a number of them (including three Catts) had developed a serious case of sun burn (black leaves, etc...). :(

Tyler


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RE: red leaves

Sound like it's time to change to Vanda's!!


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RE: red leaves

  • Posted by ttkidd Toronto ON (My Page) on
    Thu, Jun 18, 09 at 11:49

Dispite the tradgedy, it was interesting to note that the fleshy leaved varieties fared far worse than the rest. Some of my Angs which I would have expected to take far less light survived almost completely unscathed whereas the the thick leaved Catts now have large mushy black spots.

Tyler


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RE: red leaves

I have a Catt. iricolor that was given to me after that happened to it. Poor thing has no leaves at all but there is new lead growth coming on and a possible new lead developing.


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