Winter sun

[Stone]

All you Northeners, I realize your very busy frolicing in the meadows and enjoying spring at the moment but if you could spare a thought-----The long dreary days of winter are just around the corner here. My question: What are your opinions regarding giving the paphs full sun for at least part of the day in mid winter. Some days can be bright and mild but usually with the sun so low, the light can be fairly watery. I usually roll up the shade each morning to let as much sunlight as possible in but I'm not yet confident of exposing the paphs to this. What do you think?

Mike

 

[eggshells]

In winter the paphs that are on my south windows sill gets both fluorescent lighting and winter sun in the winter.

I never shut off the lights even if it's not cloudy. They get short exposure anyways. The paphs I have there aren't really the light hungry ones as well. And they look fine.

In summer half day sun and half day fluorescent.

 

[SlipperFan]

Full sun outsie? Or behind glass? Believe it or not, glass does cut down on the intensity of the sun by 25-50 %, depending on the glass.

 

[Rick]

I think I'd be farther ahead on a lot of stuff if I had pulled back my shadecloth (like I used to do about 3 years ago) this past winter.

But I didn't. I still had lots of growth anyway, and most of my stuff is on the same blooming schedule as last year.

Case in point, Dot's Max tenufolia is in full bloom now, while mine hasn't produced a bud before the middle of March for the last 2 years. I've taken it to the Memphis show in full bloom I think 3 years in a row, which is in early May.

Dot is a few hundred miles North of me, and has shorter winter days than me. So that winter shading (or unshading) appears to make a big difference.

 

[Stone]

Full sun outsie? Or behind glass? Believe it or not, glass does cut down on the intensity of the sun by 25-50 %, depending on the glass.

Behind glass. I used 'horticultural glass' to build. I'ts got a kind of rough surface on one side which is supposed to diffuse the light but I don't know if it makes much difference. All my other orchids seem to enjoy a sun bathe in winter.

 

[Ray]

I pull the shade cloth off of the GH in mid-to-late October, replacing it just last weekend.

 

[Ozpaph]

Mike, just remember many of the folks who reply from the northern hemisphere live at very different latitudes to you, where the sun's intensity is much different.

 

[keithrs]

I pulled mine off in oct. and its still off.... I have the luck of my house blocking most of my winter sun.... Not for long :clap:

 

[Lycaste53]

Mike,
do you have an instrument like a Lux-meter?

In german summer, we have daylight about 12- 16h /day (equator 12h/ every day ) Intensity of light is more than 100.000Lux on a sunny day. In winter, we have 12-8h/ day, intensity is about 50.000Lux on a sunny day.

In my greenhouse there are additional lights from end of october to mid- march, to substitute day- length

 

[emydura]

Interesting question. On top of increased light, another benefit of removing the shade cloth in winter is that it will allow more warmth in during the day. Without the shadecloth, the glasshouse should warm up nicely in the sun. Getting the daytime maximums warm enough is one of my main problems.

 

[Rick]

Interesting question. On top of increased light, another benefit of removing the shade cloth in winter is that it will allow more warmth in during the day. Without the shadecloth, the glasshouse should warm up nicely in the sun. Getting the daytime maximums warm enough is one of my main problems.

David.

I switched too alumanet a couple of years ago, which also helps (a bit) as an insulating blanket and reflects light (visible and IR) back inside the GH. So that's why I tried leaving mine in place the last couple of years.

But after 2 years I think the reflectance effect is negligable, and I think I need to pull back the shadecloth in winter for all the above you mentioned.

 

[Stone]

Mike, just remember many of the folks who reply from the northern hemisphere live at very different latitudes to you, where the sun's intensity is much different.

Thats very true, I guess the best bet is to monitor the plants and take action if they begin to look stressed.

 

[Stone]

Mike,
do you have an instrument like a Lux-meter?

In german summer, we have daylight about 12- 16h /day (equator 12h/ every day ) Intensity of light is more than 100.000Lux on a sunny day. In winter, we have 12-8h/ day, intensity is about 50.000Lux on a sunny day.

In my greenhouse there are additional lights from end of october to mid- march, to substitute day- length

No I have never used one. I've always looked at it like: If its too bright for me then it's probably too bright for the plants. If as you say your winter sun has half the intensity of your summer it will probably be similar here although more intense overall. My cattleyas go bit yellowish in winter sun but flower very well, so maybe a bit less light for the paphs?

 

[Rick]

Thats very true, I guess the best bet is to monitor the plants and take action if they begin to look stressed.

For as long as you've been growing and the quality of the plants you've shown us Mike, I don't think you'll be seeing "stress" rather than reduced growth or delayed flowering.

How does your lattitude compare to David's (for day length)?

Another complexity to winter sun that defies lattitude is average number of cloudy days (which I think you can get from a good weather source).

Although Tennessee is much farther south than Michigan (and so doesn't get the same reduction in day length or temps), we have predominantly cloudy winters. Those in England have short days AND long cloudy dreary winters. I grew up in Southern California (almost the same lattitude as Nashville, TN) but it's always sunny all winter in Los Angeles. I spent 2+ years in Yeoville, GB and didn't see the sun for 5 months!!!!

The cloudy factor is big, but can be very local. I can't say for the part of Michigan that Dot lives in, but even though it far North compared to me, the distance from the Great Lakes makes a big difference on number of cloudy winter days in parts of Michigan.

 

[Stone]

David is a few hundred miles north of me. I don't think lattitude would play a major role in this case but because he is inland, he is more subject to extremes- colder nights/hotter days. Since I moved close to the coast, The amount of foggy mornings has really surprized me. also much more cloud cover than just 50 miles further north but less extremes in heat and cold

 

[Ozpaph]

No I have never used one. I've always looked at it like: If its too bright for me then it's probably too bright for the plants. If as you say your winter sun has half the intensity of your summer it will probably be similar here although more intense overall. My cattleyas go bit yellowish in winter sun but flower very well, so maybe a bit less light for the paphs?

If the Cattleya's yellow from the sun then it'll be too light for the paphs, I think.

 

[Rick]

If the Cattleya's yellow from the sun then it'll be too light for the paphs, I think.

And then are we talking barbata types or multi's.

Philipinnense, exul, and druryi can take anything any Catt can take.

But will need to keep the suks and collosums way in the back.

 

[SlipperFan]

...
Although Tennessee is much farther south than Michigan (and so doesn't get the same reduction in day length or temps), we have predominantly cloudy winters. Those in England have short days AND long cloudy dreary winters. I grew up in Southern California (almost the same lattitude as Nashville, TN) but it's always sunny all winter in Los Angeles. I spent 2+ years in Yeoville, GB and didn't see the sun for 5 months!!!!

The cloudy factor is big, but can be very local. I can't say for the part of Michigan that Dot lives in, but even though it far North compared to me, the distance from the Great Lakes makes a big difference on number of cloudy winter days in parts of Michigan.

I think Michigan is 3rd in the US for cloudy days, especially in the Winter, after Oregon & Washington's coasts and Buffalo, NY.

 

[Rick]

I think Michigan is 3rd in the US for cloudy days, especially in the Winter, after Oregon & Washington's coasts and Buffalo, NY.

http://www.weathertoday.net/weatherfacts/cloudy_asc.php

Here's a fun website.

This is number of cloudy days per year (not just winter). Given that Nashville has very sunny summers, the 150 cloudy days account for just about the whole winter.

Michigan is probably not that different in respect to the concentration of cloudy days over winter.

 

[SlipperFan]

http://www.weathertoday.net/weatherfacts/cloudy_asc.php

Here's a fun website.

This is number of cloudy days per year (not just winter). Given that Nashville has very sunny summers, the 150 cloudy days account for just about the whole winter.

Michigan is probably not that different in respect to the concentration of cloudy days over winter.

Interesting. It's true that our summers are usually quite sunny. It's Winter that gets so dreary after awhile...