Light levels by foot candles

[Tom-DE]

For those who have grown slipper orchids under lights for a while, please tell us about the light levels by foot candles for slipper orchids.
When people talk about light levels, they often just say shade, medium light or bright light, but that just doesn't mean much since everyone might have different definitions. I understand the light meters may not be 100% accurate...but by fc, it will be easier to understand.

 

[Ray]

The AOS guides are reasonably good for the peak, noon FC's plants can handle. For paphs, they say 1000-1500 fc. That would translate to 12 hours of artificial light at 500-750.

 

[Tom-DE]

Thank you, Ray. I think I am cooking my Paphs at the current light level I am giving to them under HID light, based on the numbers you gave me...
Currently my plants are receiving 1000-2500fc...It is a new setup in the basement and I can hang the light higher to reduce the light levels...
In my head, I thought the light level for Paphs would be 800-1500fc under artificial light...

Other opinions or experiences are welcome.

 

[big923cattleya]

I agree completely. 800 to 1,500 for the vast majority of slippers. The biggest two exceptions that come to mind are what I got used to calling ‘strap leaved Paphs. Roth’s, et.al way back when. Some growers claim that Cattleya like light is good for them. But I don’t grow a lot, just too BIG for under my lights. From what I gather, some Phrags take more then 1,500 ft. Candles. Maybe not Cattleya light at 3,000, but more light then little slippers.

 

[gonewild]

Thank you, Ray. I think I am cooking my Paphs at the current light level I am giving to them under HID light, based on the numbers you gave me...
Currently my plants are receiving 1000-2500fc...It is a new setup in the basement and I can hang the light higher to reduce the light levels...
In my head, I thought the light level for Paphs would be 800-1500fc under artificial light...

Other opinions or experiences are welcome.

When using lights at a constant output you have to consider the hours per day. How many hours per day are your lights on?
As long as your foot candle rating isn't more intense than the leaves will tolerate with showing damage your not hurting the plants....just wasting electricity.
2500 foot candles is basically the maximum light in a greenhouse with 75% shade.

 

[Tom-DE]

When using lights at a constant output you have to consider the hours per day. How many hours per day are your lights on?
As long as your foot candle rating isn't more intense than the leaves will tolerate with showing damage your not hurting the plants....just wasting electricity.
2500 foot candles is basically the maximum light in a greenhouse with 75% shade.

12 hours for now and will reduce to 10 hrs...I only use the light system during winter time. My plants only have been under the light for about 2-3 weeks and I don't see any side effects yet...
Most of my plants(bigger and mature plants) are by the big windows (for winter)...but with my deepening addiction, I just have to build the new setup in the basement. I had plenty of experiences with artificial lights(HID) and the greenhouse as well...but just not so much for slippers under light...I had never focused on slipper orchids before(only about 50 Paphs and very few Phrags out of 1000+ plants collection), When I did put them under light, it was always on the shady side(~800 fc). and I understand you can grow them a bit shadier under light than in the gh or natural light.
Another question, Since I travel often and each time is about 2 weeks, I know the potted plants by the windows will be fine for two weeks, but would it be okay for small potted plants under light for 2 weeks(without watering in between)?...To advoid moving the plants out of the basement and place them by the window for two weeks or so, I am thinking they might be okay if I reduce the light hours and don't run the fan constantly. Any thought?

 

[big923cattleya]

Away for 2 weeks can present a problem. Personally 6-7 days is my limit. Even though I am retired, I could in theory, stay longer. But after three or four days of visiting someone, family or not, the conversation gets stale. That’s why I try to limit it to a 4 day maximum.
So what do I do?
Water the day before I leave.
Fill my drainage trays half full with water.
Drop my light hours from 10 or 11 to 6.
I think that doing these few little things, my plants can make it for a week easy. But 2 weeks would be pressing my luck.

A Plant Sitter could be used but I have heard horror stories about that.

I am heading to NYC for Christmas. Arrive Sunday the 22nd. Stay 22-26. Leave for home at 5am Friday, arrive Detroit 4:30 pm or so. About 525-550 miles.

 

[gonewild]

What will the humidity and temperature be during the two weeks?

 

[Tom-DE]

Bill. vacations/trips, not visiting family or friends. If they can't stay under light in the basement, I just move the little ones up and place them by the window...
For sure they will be okay under light for a week because I already have done that...
No plant sitter...one of the reasons why I got rid of my collection is that I don't have to beg people for help while we travel 2 weeks at a time. (I grew most of my plants on mounts before, as you will know how labor-intensive that is...) I can't grow the same group of orchids(I/C miniature species) anymore no matter how addictive I may become, everything must be in pots. Slipper orchids seem to be a good fit for me...especially for windowsill culture. So far, all my potted plants will be fine by the window for two weeks after the double-watering routine(I have used that method for the last 7-8 years).

 

[Tom-DE]

What will the humidity and temperature be during the two weeks?

In January, 60-65F and 50-60%

 

[gonewild]

In January, 60-65F and 50-60%

Are the little ones established and well rooted?

 

[Tom-DE]

Are the little ones established and well rooted?

yes or they will be established.

The growing area is open(not enclosed)...The light is hung 4 feet from the table and those little ones in 2.5" pot are the ones I worry about although they are nbs or bs seedlings:

 

[gonewild]

I think you can safely leave them. I would reduce the light hours to 4 hours per day. Split the hours into two parts sunrise and sunset. Give them enough light to have some daylight metabolism but not enough to have much water demand. Make darkness be your Alli.

 

[Tom-DE]

I think you can safely leave them. I would reduce the light hours to 4 hours per day. Split the hours into two parts sunrise and sunset. Give them enough light to have some daylight metabolism but not enough to have much water demand. Make darkness be your Alli.

Thank you, Lance. I am thinking about 6 hrs for the light and only run the fan when the light is on. I don't think the plants will die...I just don't want to stress them too much...maybe it is an opportunity for "a light winter rest"

 

[gonewild]

Thank you, Lance. I am thinking about 6 hrs for the light and only run the fan when the light is on. I don't think the plants will die...I just don't want to stress them too much...maybe it is an opportunity for "a light winter rest"

Two weeks of heavy cloud cover.

 

[big923cattleya]

I think it comes down to doing the best that you can leading up to your absence. Then knowing that you have done that then just trust that they will be just fine.

 

[Tom-DE]

Let's get back to the light level by fc topic...What are your shade, medium light and bright light definitions by fc (for artificial light culture)?

 

[big923cattleya]

Low light or medium shade, 800 fc
Bright shade 1,00-1,200 fc
Medium light for Oncidiums 1,800-2,000 fc
Bright light 2,200-2,400 cf for compact Cattleya and others
Bright(er) light for mature Cattleyas, the standard sized big guys, 3,000-3,200 fc
Vanda light 3,500 fc +

I am trying for 1,500 foot candles for most of my little Paphs. like helenae, sukhakulii, henryanum plus its hybrids.
For my Cattleyas like walkeriana, bicolor, intermedia, amethystoglossa, 3,000 foot candles.
Lights on 12 hours per day from June-August
11 hours a day September to November and March-May.
10 hours December-February.

 

[Adam Seward]

Bill. vacations/trips, not visiting family or friends. If they can't stay under light in the basement, I just move the little ones up and place them by the window...
For sure they will be okay under light for a week because I already have done that...
No plant sitter...one of the reasons why I got rid of my collection is that I don't have to beg people for help while we travel 2 weeks at a time. (I grew most of my plants on mounts before, as you will know how labor-intensive that is...) I can't grow the same group of orchids(I/C miniature species) anymore no matter how addictive I may become, everything must be in pots. Slipper orchids seem to be a good fit for me...especially for windowsill culture. So far, all my potted plants will be fine by the window for two weeks after the double-watering routine(I have used that method for the last 7-8 years).

What is the double-watering routine?

 

[Tom-DE]

What is the double-watering routine?

Water the potted plants 2 days before the trip really well, then water them again just before your trip. Follow this routine, mature Paphs(in 3" or bigger pot) will be fine in the house/windowsill for 2 weeks... no visible stress.