Light levels by foot candles

[Adam Seward]

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.

Thanks Tom!

 

[hkunberger]

https://www.slippertalk.com/threads/vacation-watering.51956/reply?quote=715711
I found this very helpful when I had to leave for several weeks this summer.

 

[Tom-DE]

Bill, thank you for your interpretations on artificial light levels by fc.
I am hoping I can hear from different hobbyists as well on light levels(by fc, artificial lights) for slipper orchids.

 

[big923cattleya]

Oh Tom, it was my pleasure! Anytime.

 

[Morja]

I'll add my two cents to the light part of this discussion. Understand that I am very inexperienced in comparison to most of you, but I added lights fairly recently to my collection and this is what has worked for me with good growing/blooming results with less than a year of use.
Instead of FCs I use PPFD. I downloaded an app called Photone, which, while not a $200 professional light meter, works well enough. Your local orchid society might have a member with an official meter you could borrow which would be ideal.
I follow the recommendations on our fellow member's blog Here But Not:
https://herebutnot.com/light-recommendations-ppfd-par-for-orchids-and-houseplants/
Here is a quote from this particular blog post:
"Light Suggestions for Orchids (PPFD or PAR Recommendations)
Low-Light Orchids (Mottled-Leaf Paphs, Jewel Orchids, Phals)
40–80 umol/m2/s PPFD (20 umol/ft2/s)
Moderate-Light Orchids (Onc, Phrags, Epidens, Dends etc)
80–150 umol/m2/s PPFD (30-40 umol/ft2/s)
High-Light Orchids (Cattleya)
150–350 umol/m2/s PPFD (50-100 umol/ft2/s)
Very High-Light Orchids (Vandas)
350–600 umol/m2/s PPFD (50-100 umol/ft2/s)
*Converting meters to feet: 1m = 3.28ft
**NOTE: These are general suggestions not EXACT numbers; you can expect that +/- 50-100 umol/m2/s is likely okay and individual orchid species may be adapted to a range beyond these numbers—for example, a lot of strap-leafed paphs can take closer to 150 umol/m2/s. I encourage you to use this information to help you benchmark where your light should be, but as with all things related to horticulture and plant care, adjust based on your conditions and how your plants perform, look and grow."

Oh, and my two cents on a plant sitter (if you get one) is, if you have any phrags with wet feet... make sure you make it physically impossible to give any other plants wet feet. I learned that the hard way when I came home to a paph drowning in its decorative pot. It has thankfully recovered somewhat and is about to bloom. But a lot of its roots tips stopped growing.

 

[hkunberger]

Oh, and my two cents on a plant sitter (if you get one) is, if you have any phrags with wet feet... make sure you make it physically impossible to give any other plants wet feet. I learned that the hard way when I came home to a paph drowning in its decorative pot. It has thankfully recovered somewhat and is about to bloom. But a lot of its roots tips stopped growing.

Oh I’ve been there! I asked my husband to take care of the orchids and the roses for a well. Wrote everything out, color coded the various orchids. It seemed foolproof.
Anyway, when I got home the roses were bone dry and the orchids were swimming in six inches of water . Thank goodness I wasn’t going long.

 

[big923cattleya]

A simple $38 light meter from Amazon that gives me a combined instant reading of not only foot candles but humidity and temperature as well, seems simple and easy.
Plus I am dealing with recommendations for light intensity gathered from orchid books, lectures and periodicals from 1975 to 2008.
Why 2008, that is kind of when books fell out of popularity for me and internet research took over.
Well that and experience. Your orchids will tell you for the most part, if the light is right in your conditions. I know that time marched on and new techniques are developed but man o’ man, I have enough trouble understanding foot candles.

 

[hkunberger]

yeah the foot candle thing feels like something g from a different era.

 

[Tom-DE]

I don't really try to understand FC or PPFD, just like the temperature F vs C. Feel free to use both, conversion is easy if you google for the conversion chart. What matters the most is the numbers.

 

[Morja]

I don't really try to understand FC or PPFD, just like the temperature F vs C. Feel free to use both, conversion is easy if you google for the conversion chart. What matters the most is the numbers.

Haha that's the spirit honestly, I have no idea what either truly means

 

[Ray]

Light levels, as basic as it may seem, is full of potential pitfalls.

We get concerned about “what is sufficient,” for example, but rarely think about what is excessive. Despite being told that “more light delivers more blooms”, people forget that in some plants, more light results in short inflorescences and fewer blossoms. Phalaenopsis is a good example of that.

Knowing there are a range of chemical processes going on within the plant, I figure some reaction rates are affected by light level (other than the obvious case of photosynthesis), either directly or because the the heat generated, and throwing off the natural balance of the reactions may have other effects.

It’s pretty well established that different plants need different daily or seasonal temperature “schedules”, so it seems logical that the same is true of light. Hell, for all I know, maybe the shifting spectrum of sunlight, and not just the intensity, from dawn to noon to dusk, or even seasonally, plays a role.

We are dealing with the “Goldilocks” of the plant world, after all, and she was pretty damned picky.

 

[terryros]

The light source is important in this discussion. While there may be plant benefits from some infrared or ultraviolet light present in natural sunlight, most horticultural studies focus on light in the “photosynthetically active range” (PAR) where photosynthesis occurs. The good plant meters measuring “peak photon flux density” almost all have filters that measure only in the PAR range. You are more sure your plants are getting light that is not significantly below or above a good range for the type of plant, regardless of the light source. If you are using artificial light and don’t know its spectrum, you could measure foot candles with a general light meter and be off either high or low from the true PPFD in the PAR range. If you have even a reasonable size collection of reasonably expensive orchids, I think the cost of a good PPFD (I use an Apogee 500 series quantum flux meter) is worth preventing under-performing plants from over or under illumination.

 

[Tom-DE]

Light levels, as basic as it may seem, is full of potential pitfalls.

We get concerned about “what is sufficient,” for example, but rarely think about what is excessive. Despite being told that “more light delivers more blooms”, people forget that in some plants, more light results in short inflorescences and fewer blossoms. Phalaenopsis is a good example of that.

Knowing there are a range of chemical processes going on within the plant, I figure some reaction rates are affected by light level (other than the obvious case of photosynthesis), either directly or because the the heat generated, and throwing off the natural balance of the reactions may have other effects.

It’s pretty well established that different plants need different daily or seasonal temperature “schedules”, so it seems logical that the same is true of light. Hell, for all I know, maybe the shifting spectrum of sunlight, and not just the intensity, from dawn to noon to dusk, or even seasonally, plays a role.

We are dealing with the “Goldilocks” of the plant world, after all, and she was pretty damned picky.

Many good points here...I totally agree with you, Ray.

 

[Tom-DE]

yeah the foot candle thing feels like something g from a different era.

try the old method used by the boomers--judge the light by hand shadow on the plants

 

[hkunberger]

To be painfully honest, I mostly guess at appropriate light levels and let the plants tell me if they need things adjusted. Leaves too pale, I back off on the light. Leaves too dark, I ramp it up a bit. I’ve found that individual
pants have a pretty strong preference for certain spots on the shelf. Sometimes even a very short distance is the difference between “reasonably happy” and “perfectly content”.

 

[Tom-DE]

To be painfully honest, I mostly guess at appropriate light levels and let the plants tell me if they need things adjusted. Leaves too pale, I back off on the light. Leaves too dark, I ramp it up a bit. I’ve found that individual
pants have a pretty strong preference for certain spots on the shelf. Sometimes even a very short distance is the difference between “reasonably happy” and “perfectly content”.

Everybody does that because there are so many other factors you must consider...but a basic number whatever that might be does help for a good start. "shade" "medium" or "bright" don't tell me much but give me just guessing... On top of that, greenhouse/natural light and artificial light are quite different.

 

[terryros]

If you are young and just starting out, you have years to just try things and watch your plants and make corrections. If you are older, probably better to try and get things correct more quickly. I still buy green bananas, but I don’t buy small orchid seedlings any more!

 

[hkunberger]

If you are young and just starting out, you have years to just try things and watch your plants and make corrections. If you are older, probably better to try and get things correct more quickly. I still buy green bananas, but I don’t buy small orchid seedlings any more!

Well said!

 

[Roots]

If you are young and just starting out, you have years to just try things and watch your plants and make corrections. If you are older, probably better to try and get things correct more quickly. I still buy green bananas, but I don’t buy small orchid seedlings any more!

Oh so true!

 

[Califoutdoors]

…but I don’t buy small orchid seedlings any more!

Yep!