Winter Light Question
 

I have a greenhouse that is situated in a way to where during the summer months it is protected from the harsh late afternoon sun. Come Nov I removed the shade cloth and tested the light to have an idea how bright the light is. I tested around 11am-12pm and I was getting around 6000+FC from the top of my benches.

Now because the photo-period was still rather long here in Maryland I decided to still keep my orchids and other shade loving plants on the bottom shelf of my bench system where they were receiving from 1000-2000 FC. They are doing well, bloomed and sending out shoots.

Would it be safe to move the Orchids to the top of the bench now? I have not tested the light but I'm getting around 5-6 hours of direct light which I believe will still be in the 5000-6000 FC range.

What do you greenhouse growers do during the winter months when the photo-period is shortening?

Here is my current collection:

*Bc. Angel Lace
*Sand. Black Start Pacific Red Star
*Mtssa. Fitch 'lzum'
*Unlabled Intergeneric Oncidinae
*Unlabled Paphiopedilum

I am about 30 miles north of Philly, and I pull my shade cloth in mid-October, leaving all of the plants where they were. No issues whatsoever.

I really have to question your light readings, though. 6000 fc in mid-winter seems awfully high for your latitude, even at midday.

During the winter, light is much less intense. Towards spring you have to be careful though. It seems to sneak up on you and suddenly they can be burned.

I checked the light again. At 11:30am I'm getting max 3200 FC. Over the last month-month and a half the light intensity has really fallen off. I'm going to leave them where they are for now.

I was more worried about the cooler air on the lower level of the benches but I have not seen any ill effects yet. They seem to be fine. This is my first winter with this greenhouse so it is a learning experience.

Thanks for the help.

You should have fans running 24/7 in the greenhouse. It keeps the air buoyant and prevents such stratification.

I was going to say "6000FC" You lookinhg sod! That is summer for us!!!!!!!!!

There is a greenhouse forum here with a lot of more senior orchid people who work with greenhouses regularly. I'll bet they can help you?

I sort of have the same questions. The light drops below a bunch of trees so I get nothing but indirect light in winter. I don't think its close to 6000fc - probably more like 2000 midday - which is sort of perfect for me...

the short days are a problem though. I supplement with 2 LEDs (240W (i think) blackstar lamps). but this is pretty new. The plants have appreciated the extra light though. If you are getting 6000 during the day, I wouldn't worry too much. I am trying to get 11 hour days, and not all the plants are getting the supplemental light - my Cattelyas are just on the edge - I just rely on their food storage mechanism to get through the winter, same with my Cyms.

We'll see how my paphs / bulbos / pleuros do.