# Paphiopedilum... what’s up?



## Phred (May 29, 2019)

Elongated growth... Can anyone tell me why Paphiopedilum grow like this sometimes.


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## TyroneGenade (May 29, 2019)

Are you growing under lights? What type of lights?


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## Phred (May 29, 2019)

I do grow under lights. They are SunBlaster T5 - 54 watt high output bulbs with reflectors.


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## Ray (May 30, 2019)

I would suspect insufficient light.

How many bulbs, covering what area? How far above the plants? How old are the bulbs?


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## Phred (May 30, 2019)

There is one 4’ bulb over each shelf which is about 18” wide. The lights are about 8-10” above the plants. They were burning some of the plants so I have them shaded. I leave them on for 10-12 hours.


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## Phred (May 30, 2019)




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## Phred (May 30, 2019)




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## musa (May 30, 2019)

I'd suspect to less light, too. I grow under two 36 watt each 120 cm bulbs (T8) on shelves of 30cm. They are on for 15 hours a day, additional to daylight from the window. I use fluora, these are optimized for the demands of plants.
I never had the impression that it is too much light.
The Maudiae types sometimes tend to have elongated growth.
BTW your setup is very impressive!


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## BrucherT (May 31, 2019)

Following in order to learn. Your grow is staggering to me. I grow in windows and I’m limited in terms of space...if I had a room like yours....


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## NYEric (May 31, 2019)

I don't think too little light is the reason. The reason does not matter. You will have to re-pot to address the stolonous growth. Nice, neat growing area; thanks for sharing.


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## TyroneGenade (May 31, 2019)

Your growing area is very impressive. Inspirational, even. 

Download a lux meter onto your phone (I assume you have smart phone, otherwise grab a teenager) and measure the lux. You can estimate about 20 PPFD per 1000 lux. I think Ray or Naoki was suggesting 100 PPFD is fine for our Paphs. The spectrum might be the issue rather than light volume. Too much far-red relative to red and blue light can cause stem elongation. Your shading devices might be filtering out the blue and red and letting too much far red pass?


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## Paphluvr (May 31, 2019)

When I was growing under lights my main bench had four 8' T12 HO bulbs. That was over a 8' x 30in. wide bench at approx. the same distance above the plants as you're discussing and I never had a problem with leaf burn. I also had a two ft. box fan that circulated the air whenever the lights were on. Could the yellowing of the leaves be related to heat rather than too much light? By the way, the lights were on 14hr/day, shortened to 12 in the winter.


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## Ray (Jun 1, 2019)

The light meter suggestion is a good one. I'll bet your shade has cut the light intensity far more than it appears to the human eye.


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## spujr (Jun 1, 2019)

TyroneGenade said:


> Your growing area is very impressive. Inspirational, even.
> 
> Download a lux meter onto your phone (I assume you have smart phone, otherwise grab a teenager) and measure the lux. You can estimate about 20 PPFD per 1000 lux. I think Ray or Naoki was suggesting 100 PPFD is fine for our Paphs. The spectrum might be the issue rather than light volume. Too much far-red relative to red and blue light can cause stem elongation. Your shading devices might be filtering out the blue and red and letting too much far red pass?



I agree that the spectrum might be an issue.

Also you probably would be ok to extend the light interval to 14hrs. I've been growing my plants under 20hrs with no problems aside from the electricity bill (I since stopped).

Plants (in general) tend to have that elongated growth when crowded together or perceive competition from neighboring plants. Your set up doesn't appear to be too crowded but it might help spreading the pots out more, if space allows it.


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## spujr (Jun 1, 2019)

Also, I'm assuming you haven't been applying any pesticides/chemicals? Some contain growth hormones that might cause similar symptoms.


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## Ray (Jun 1, 2019)

spujr said:


> Also, I'm assuming you haven't been applying any pesticides/chemicals? Some contain growth hormones that might cause similar symptoms.


True enough. If you use a growth stimulant that contains predominately cytokinins (kelp extracts made from _Ascophyllum nodosum_ fall into this category), they will stimulate plant growth first, which in turn stimulates root growth. If the conditions are a bit awry, that plant growth can end up being leggy.

I doubt the spectrum is the issue. Yes, the plant needs light in the PAR (400-700 nm) range of the spectrum, but unless the light is really skewed to either end of that range, it's probably OK. White light is actually reasonably good about that.

Biologically, plants must have a certain "volume" of light, the intensity x time, both of which can be adjusted - within reason - to compensate for a change in the other. Each plant has its own range of volume needed to grow and bloom well. Too little of too much can be a negative.


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## spujr (Jun 1, 2019)

Ray said:


> True enough. If you use a growth stimulant that contains predominately cytokinins (kelp extracts made from _Ascophyllum nodosum_ fall into this category), they will stimulate plant growth first, which in turn stimulates root growth. If the conditions are a bit awry, that plant growth can end up being leggy.
> 
> I doubt the spectrum is the issue. Yes, the plant needs light in the PAR (400-700 nm) range of the spectrum, but unless the light is really skewed to either end of that range, it's probably OK. White light is actually reasonably good about that.
> 
> Biologically, plants must have a certain "volume" of light, the intensity x time, both of which can be adjusted - within reason - to compensate for a change in the other. Each plant has its own range of volume needed to grow and bloom well. Too little of too much can be a negative.



I agree with what you say about light volume.

However I have reasons to suspect the spectrum could be a factor. In onions (bulb=modified stem, also a monocots), we seen bulb shape greatly affected by light intensity. If you plant an onion by itself and it receives high light intensity of full spectrum wavelengths it will have the tendency to flatten out, whereas in high density plantings under low light intensity with a modified spectrum of light the shape is elongated. Plants "perceive" crowding through the leaf canopy light reflection, ie the light being reflected off another leaf which is a specific ratio of more wavelengths of one over the other.

Of course, this is onion, not orchids, but there may be some relationship.


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## Ray (Jun 1, 2019)

spujr said:


> I agree with what you say about light volume.
> 
> However I have reasons to suspect the spectrum could be a factor. In onions (bulb=modified stem, also a monocots), we seen bulb shape greatly affected by light intensity. If you plant an onion by itself and it receives high light intensity of full spectrum wavelengths it will have the tendency to flatten out, whereas in high density plantings under low light intensity with a modified spectrum of light the shape is elongated. Plants "perceive" crowding through the leaf canopy light reflection, ie the light being reflected off another leaf which is a specific ratio of more wavelengths of one over the other.
> 
> Of course, this is onion, not orchids, but there may be some relationship.



You changed three things: planting density, light level, and spectrum. How can you possibly know that it was the spectrum that affected the bulb shape?

Passing through a forest canopy, light intensity is diminished and the spectrum changes to having more green in it, due to leaf absorption and reflection properties. In Phred's case, the shading is white, so should have very little influence on the spectrum.


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## spujr (Jun 1, 2019)

Phred said:


> I do grow under lights. They are SunBlaster T5 - 54 watt high output bulbs with reflectors.


This the 2700k or the 6400k model?


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## spujr (Jun 1, 2019)

Ray said:


> You changed three things: planting density, light level, and spectrum. How can you possibly know that it was the spectrum that affected the bulb shape?
> 
> Passing through a forest canopy, light intensity is diminished and the spectrum changes to having more green in it, due to leaf absorption and reflection properties. In Phred's case, the shading is white, so should have very little influence on the spectrum.



Well we know from several scientific studies. We also know from other studies the effects of blue, red, and far red ratios on plant growth.

But, what you say about the white shading is correct. However the light source doesn't account for the reflected light coming off the neighboring plants. 

I don't think light intensity is not a factor here, however, I wouldn't outright dismiss the spectrum influences.


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## TyroneGenade (Jun 1, 2019)

We do not see far red. The white shading could filter it out and we wouldn't be any the wiser. In filtering out the far red the shading would also filter out a lot of heat.


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## musa (Jun 2, 2019)

spujr,
you have the light on for 20 hours? Doesen't that have a negative effect on the growth of the plants if they have a night period of only 4 hours?


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## Ray (Jun 2, 2019)

Yes, spectra affect growth. So does intensity.

I seriously doubt, however, that light reflection from adjacent leaves has much impact, if any. In a rainforest environment, light from the broad sky has to pass through a long, circuitous path, reflecting off of multiple leaves on its way through. That both diminishes the intensity (compensated for by the huge area - a whole lot of dim light combining to become adequate light) and significantly shifts the spectrum.

To plants growing on a bench, the incident light intensity is orders of magnitude great than anything reflecting off of adjacent plants, so overwhelms it. That, and the fact that the amount of light reaching a plant from those around it is likely minuscule considering they are side-by-side.


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## TyroneGenade (Jun 2, 2019)

Ray said:


> Yes, spectra affect growth. So does intensity.



I agree with Ray's position on this. Light intensity is the easiest variable to test and, all other arguments aside, should be the first thing tested. You can get a cheap luxmeter online if you don't have a smart phone that can support a lightmeter app like "lux light meter". The plants aren't crowded (mine are more crowded but I don't see this issue) so light spectrum would be the _*next *_hypothesis to test.

I don't think running the lamps for 20 hours is a good idea. The plants do need to rest, and as many orchids are (if I recall correctly) CAM plants they need that night period to prepare their metabolism for the next day. Perhaps Naoki can weigh in once we have the lux meter readings?


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## spujr (Jun 2, 2019)

musa said:


> spujr,
> you have the light on for 20 hours? Doesen't that have a negative effect on the growth of the plants if they have a night period of only 4 hours?



I want to be careful about what I say: I'm not recommending 20hr duration. However, in Phreds case I think he would be "ok" to extend to 14 for at least during the summer months. Also to clarify I don't think the duration would improve or solve the leggy growth habit, but I don't think it would hurt. 

In my experience thus far, I haven't seen any problems with going 20hrs with orchids. It is a common practice among many crop species (wheat, corn, tomatoes, rice) in speed breeding where they can generate 2-4x the generation turnaround per year.

That said, my experience doing this with orchids is limited to a few months and a few species and is not a true replicated experiment with proper controls, so again I would caution in applying it to your conditions. 

Like I said, the plants I have doing this don't appear to be negatively impacted by the extra long days. 

This is a photo of a malipoense compot I got in end of March:



Same mid May:



Yesterday (June 1st):



I can't say they are growing slower or faster. All I can say is that they appear fine and grossin growing well.


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## spujr (Jun 2, 2019)

TyroneGenade said:


> I agree with Ray's position on this. Light intensity is the easiest variable to test and, all other arguments aside, should be the first thing tested. You can get a cheap luxmeter online if you don't have a smart phone that can support a lightmeter app like "lux light meter". The plants aren't crowded (mine are more crowded but I don't see this issue) so light spectrum would be the _*next *_hypothesis to test.
> 
> I don't think running the lamps for 20 hours is a good idea. The plants do need to rest, and as many orchids are (if I recall correctly) CAM plants they need that night period to prepare their metabolism for the next day. Perhaps Naoki can weigh in once we have the lux meter readings?


You are right about CAM and I realize my crop examples in my post above are either c3/c4 types. So again, caution in the wind. I think skeptism is due, but I'm trying it anyways .


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## spujr (Jun 2, 2019)

One of the reasons I asked Phred earlier which bulb model he is using is because there is a big spectrum difference between the 2700k and 6400k (both are 48" 54W):





I am not familiar with these types as I use something different but it appears the 6400 has almost no red spectrum.


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## Ray (Jun 3, 2019)

I think those spectra plots may be a bit deceiving. You’ll notice that both are normalized on the green spike to an arbitrary value of 1.0. 

In fluorescents and white LEDs, the color temperature is a correlated value- correlated to what a true, black body spectrum of that temperature would look like to the human eye. As the eye is most sensitive to green, it is logical that the 6500 lamp has a lot more green than the 2700 lamp. I’ll bet that if the true intensities were plotted, those other parts of the spectrum would be better represented. 

That said, in both types of light sources, the lower-temperature phosphors do tend to have a broader presence in the reds.


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## southernbelle (Jun 3, 2019)

TyroneGenade said:


> I agree with Ray's position on this. Light intensity is the easiest variable to test and, all other arguments aside, should be the first thing tested. You can get a cheap luxmeter online if you don't have a smart phone that can support a lightmeter app like "lux light meter". The plants aren't crowded (mine are more crowded but I don't see this issue) so light spectrum would be the _*next *_hypothesis to test.
> 
> I don't think running the lamps for 20 hours is a good idea. The plants do need to rest, and as many orchids are (if I recall correctly) CAM plants they need that night period to prepare their metabolism for the next day. Perhaps Naoki can weigh in once we have the lux meter readings?


I grow under LED tube lights and adjust the daily light interval from 14 hours/day in May to 11 hrs/day in November. It is a gradual change of 30 min/day from month to month. Max/min temps in the room are adjusted accordingly as well. From what I’ve read longer light interval does not make up for insufficient intensity.


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## southernbelle (Jun 3, 2019)

spujr said:


> One of the reasons I asked Phred earlier which bulb model he is using is because there is a big spectrum difference between the 2700k and 6400k (both are 48" 54W):
> View attachment 15738
> 
> 
> ...


My bulbs with the 11-14 hr daily light interval (referred to in the reply below) are 5,000k. Here are my specs.


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## spujr (Jun 3, 2019)

southernbelle said:


> View attachment 15745
> 
> My bulbs with the 11-14 hr daily light interval (referred to in the reply below) are 5,000k. Here are my specs. View attachment 15745
> View attachment 15746



I have a similar light setup using the 5600K model but @ 20W instead of 40.


I am still learning about what all the numbers mean, but the nice thing is that this info is useful for my work application as well as my hobby (orchids)! I'm thinking it might be interesting to explore the different bulb types (3200K & 5600K) to artificially "mimic" a day, where the 3200K bulbs are turned on a few hours in the morning and late afternoon and then the 5600K turned on during the day. I suspect the effects would be minor in relation to plant growth but still fun to try.


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## southernbelle (Jun 4, 2019)

spujr said:


> I have a similar light setup using the 5600K model but @ 20W instead of 40.
> View attachment 15749
> 
> I am still learning about what all the numbers mean, but the nice thing is that this info is useful for my work application as well as my hobby (orchids)! I'm thinking it might be interesting to explore the different bulb types (3200K & 5600K) to artificially "mimic" a day, where the 3200K bulbs are turned on a few hours in the morning and late afternoon and then the 5600K turned on during the day. I suspect the effects would be minor in relation to plant growth but still fun to try.


That would more closely resemble natural daylight, I think (with noon being the most intense part of a sunny day) which is when the recommended Foot Candles for each type of orchid are measured. I’m not sure of the benefit, though. It was recommended (and I’ve found) with my lights, that with the constant light for the entire duration of the daily light interval, one-half the recommended Foot Candles for each type of orchid is what is needed. That enables me to raise the lights to 24-30” above leaf canopy which is glorious headroom (with 3 tubes in each fixture over Catts and 1 tube over Paphs and Phals. I can’t tell you the foot candles, but it it really low (relatively speaking) because I measure PAR, but everything is growing and blooming well (except for the catts I repotted at the wrong time when I was still learning). But, they are coming back with new leads, so there is hope even when we mess up. Happy growing.


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