Need Advice About How Much Light for roth. Hybrids

[Jpari]

I am curious about what the experts do in this situation. Do you grow roth x Parvi. hybrids and roth x Brachy. hybrids in very bright light like the other multi floral type roth. hybrids or do you give them more subdued light like a Maudiae type Paph.? I have wondered how to grow these types of hybrids for quite some time and now it is time to see what others do in order to grow these well and flower them. Thanks in advance for any help that you may provide.

 

[CarlG]

As a general principle, I give my plant as much light as they can take without burning. Paphiopedilum rothschildianum and its hybrids can take at least as much light as a cattleya. If adapted to the light from spring, I've found that sun from morning to around 1pm is fine, even when the daytime temperature approaches 100F.

 

[Ozpaph]

same, 'higher' light for all roth hybrids cf pure parvis, maudiaes etc

 

[Tom-DE]

same, 'higher' light for all roth hybrids cf pure parvis, maudiaes etc

The roth and parvi(most of them) might like/can handle "higher" light but why Maudiae type? I thought they were mostly shade-loving hybrids...
Does anyone else grow Maudiae type of Paphs under "higher" light? I don't grow Maudiae hybrids but I am currently growing some species along that line...

 

[Tom-DE]

and yes, Brachy type can handle higher light as well(in general).

 

[Nelson Wong]

Most of my roth, eachy, Roth hybrid, and mutifloral hybrids are under phrag level light. Which is around 180-230ppfd for me.

They get 12 to 14 hrs a day and there are no burn damage.

 

[JustinR]

I grow roth x parvi hybrids bright and they are growing pretty fast. They are famous for never blooming, time will tell

 

[big923cattleya]

I have some related information to add to this discussion.
I am strictly an under lights grower. I have some 2 dozen Roth plants, both species and hybrids. Up until recently, the last 2 years of growth of these plants, were at best, disappointing! ( I summer them outside for 4 1/2 months)
That has changed recently. Why? They are now under a light fixture with 6 tubes. I am still a footcandle guy and they have gone from 1,300-1,500 footcandles a year ago to
2,500-2,800 footcandles now! ( those numbers were taken using a light meter held under the center of the tubes @ 3”, 6”, 9” and a foot below.
Since they came in two months ago, they have perked up noticeably. The leaves are greener, standing more upright and the new growths are more upright. I took those observations as good news.
I’ll include an image.

 

[gonewild]

How many foot candles were they getting for the months outside?
Were they getting more or less light while outside?

 

[big923cattleya]

I never measured the footcandles out side. I have a home that is very shaded on the south side. My only spot to put my orchids is on the north side. There they all get between 2-3 direct hours of sun.
As the sun’s angle changes from May through September when they come back inside, the time in the sun does change a little. But the sunny hours are in the morning, generally between 8am and 11am. When it rises in the morning, this is where the sun hits first.
In year one, I tried them further out in the sun, but they were showing signs of sunburn.
I had a red maple tree that I was thinking of putting them under for the summer of 2019 in dappled light, but that tree had limbs drop due to a fungal problem. So no orchids there. Dropping branches forced me to have it taken down in 2021.
So I am kind of forced to keep them in their current spot.
I am too old to go the greenhouse route nor did I want to create an outdoor structure with shade cloth and such. Either they were going to live with 2-3 hours of morning sun or not.
They grow well outside but don’t seem to bloom very well. I hung a few plants from pipes just below my gutters this summer, things like C. walkeriana, C. intermedia, L. anceps and such. They did better. But my big Paphs. seemed to grow just blah!!
This whole orchid thing is a work in progress trying little improvements every summer.

 

[gonewild]

Either they were going to live with 2-3 hours of morning sun or not.

Is that. 2-3 hours of direct sun or shaded?

 

[Tom-DE]

How many foot candles were they getting for the months outside?
Were they getting more or less light while outside?

For Paths, the average fc is more than 2500fc in my growing area(north-facing), with minimum morning sun(direct sun) and late afternoon/early evening sun(some spots). Late afternoon sun could cause sunburn, so watch out in the early season.
They do get more sun outside in terms of footcandles, compared to artificial lights, as much as 2800fc for my Paphs...Plants will grow and bloom better if you grow them outside during the warmer months. Some gh growers even make the effort to do the same thing. I always tell people that if you can't do the daily temperature change, the next best thing is the natural seasonal change.
but you can't grow cool growers outside like PNG Dendrobiums and Pleurothallids(with few exceptions).

 

[gonewild]

It would be interesting to know the outdoor foot candles of the 3 hours to make a mathematical conversion to DLI to see how it compares to 12 hours of 2500 fc LEDs.

 

[Tom-DE]

It would be interesting to know the outdoor foot candles of the 3 hours to make a mathematical conversion to DLI to see how it compares to 12 hours of 2500 fc LEDs.

Not sure I understand your question correctly, but outdoor light is not measured by only the 2-3 hours direct sun... Like the greenhouse light, the strongest is around noon to 1 pm...you take that for the most light your plants will get, but the light(level) will be less before and after the peak. Artificial light is constant and that is why we can grow our plants in much less fc under light... gh and under-light culture are quite different.
You can find a conversion chart(for light) online for whatever conversions you prefer.

 

[gonewild]

I said 2-3 hours because bigcat said that's how much sunlight his plants get outside with the impression that the paphs grew better under 2500- 2800 fc inside than the light received outside.. Knowing the foot candles of the sunlight he gets will allow conversion of his outdoor light to a DLI level. With that known level a compassion can be made between his outdoor and indoor light values.
Does that make sense?

 

[Tom-DE]

I said 2-3 hours because bigcat said that's how much sunlight his plants get outside with the impression that the paphs grew better under 2500- 2800 fc inside than the light received outside.. Knowing the foot candles of the sunlight he gets will allow conversion of his outdoor light to a DLI level. With that known level a compassion can be made between his outdoor and indoor light values.
Does that make sense?

got it...but I let Bill answer that one.

 

[Tom-DE]

That has changed recently. Why? They are now under a light fixture with 6 tubes. I am still a footcandle guy and they have gone from 1,300-1,500 footcandles a year ago to
2,500-2,800 footcandles now! ( those numbers were taken using a light meter held under the center of the tubes @ 3”, 6”, 9” and a foot below.
Since they came in two months ago, they have perked up noticeably. The leaves are greener, standing more upright and the new growths are more upright. I took those observations as good news.
I’ll include an image.

You should measure the light at the plant leaves level...
I would like to see a picture of your Paphs setup(not your Cattleya) and see how upright your roths/roths hybrids are...My roths(only one) new growths are always upright but old growth after bloom will level out eventually. Currently, I am cooking a couple of roths hybrids(mature plants) with the same fc(HID sodium light) as yours, ~2700fc...

 

[Ozpaph]

The roth and parvi(most of them) might like/can handle "higher" light but why Maudiae type? I thought they were mostly shade-loving hybrids...
Does anyone else grow Maudiae type of Paphs under "higher" light? I don't grow Maudiae hybrids but I am currently growing some species along that line...

cf = 'compared to' ie as opposed to/in contrast to.

 

[Tom-DE]

cf = 'compared to' ie as opposed to/in contrast to.

that is a bit confusing...since parvi is included. Parvis certainly can grow under much higher light, just as much as roths. IMO, but never mind...