Lumens for my new phalaenopsis

[SouthPark]

Here's a nice link about lux and lumens.

Click Here.

For orchids, the lux quantity is expected to be the more relevant quantity of interest here. Or more immediately useful for this situation.

[SouthPark]

I forgot to mention that the details of the link are quite general - but helps to get the point across.

I think a lot of online information about the topic of 'lux' misses out certain important details, such as the assumed kind of lighting (eg. uniform light flux distribution), and distance of light receiving surface (ie. its distance from the light source), and shape of surface, and surface area of surface.

But that's ok - since we know that leaving out important details is the life story of lots of information sources.

[Ray]

Originally Posted by ghuylar

Generally, the more light the better!

Not for all plants. Take phals, for example. They're deep-shade plants in nature., so more light can translate to fewer, shorter-lived blooms.

When I moved to "better" conditions by building a greenhouse and moving my plants from indoors, I was confused as to why my phals bloomed less than they had. Now that I'm (decades later) back to windowsill growing - north-facing, no less - after about a year of adjustment, my phals are becoming more floriferous again.

The best-blooming phals I've ever seen were in a very hot, very humid greenhouse that was SO coated with algae, absolutely no sunlight got in.[COLOR="Silver"]

A foot-candle is a lumen per square foot. A lux is a lumen per square meter. Imperial and metric versions of the same measure.

Lumens are used to specify the total light output from a source. Both foot-candles and lux tell you how much is striking an area of surface. Certainly, lumens can be used to determine the intensity at the plant, but that is not what it is intended for.

What is actually most important is the volume of light that reaches the plant over the course of a day, known as the Daily Light Integral (DLI), and that is measured in micromoles of photons.

[wisdomseeker]

I hesitated replying to the OP's original post because I know the subject of lighting can become very complicated, and often produces a lot of contention. It was because of the OP's second post, I decided to reply.

I'm sure many people follow the KISS principle... they really don't care about technical jargon or how one comes to the conclusion of producing an answer... they just want a simple answer to their question.

I would venture a guess that many go to a good website for cultural information about an orchid (e.g., Andy's orchids). You look up the plant that interests you and find a recommendation for light. Example: shade; 500-1500 footcandles (indirect low light, slight shadowing).

More than likely, one starts thinking to themselves: how do I know if my light is within the 500-1500 footcandle range? You really don't know unless you can figure out how to measure that light. For me, having an inexpensive lux meter helps to do just that. It's not perfect (and surely does not compare to using a good Par meter), but it definitely gives a good 'guesstimate' to help figure out if my light is within the range recommended by another.

817 x 10 = 8170 lux, which converts to 759 footcandles. I think most orchid growers realize it's not just a matter of light, it's more of: "am I providing a balanced growing environment for my plant" (knowing that light/temperature/water/food/air makes up the team for a balanced growing environment).

[camille1585]

Originally Posted by Ray

Not for all plants. Take phals, for example. They're deep-shade plants in nature., so more light can translate to fewer, shorter-lived blooms.

When I moved to "better" conditions by building a greenhouse and moving my plants from indoors, I was confused as to why my phals bloomed less than they had. Now that I'm (decades later) back to windowsill growing - north-facing, no less - after about a year of adjustment, my phals are becoming more floriferous again.

The best-blooming phals I've ever seen were in a very hot, very humid greenhouse that was SO coated with algae, absolutely no sunlight got in.

After years of wondering why my Phals produce smaller spikes, I think I now know why, thanks to you! Before moving to my current appartment in 2014, I kept all my Phals on the only windowsill I had, facing north-east and I had tons of blooms per spike. I moved and the orchids went to a south facing window, with the Phals getting bright indirect light with some direct sun late in the day. The Phals weren't doing well, but I put it down to the long period of neglect when I was finishing my PhD. Several years later, even with good care they never flowered as great as they did pre-2014.... I think I'm going to move them to the lowest shelves and add a fairly thick sheer curtain to the lower half of the window.

[SaraJean]

Originally Posted by Ray

Not for all plants. Take phals, for example. They're deep-shade plants in nature., so more light can translate to fewer, shorter-lived blooms.
[COLOR="Silver"]

well that answers a question I didn’t even know I had

I’m not really a Phal grower but I do have a few. The little NOID gifts from friends always bloomed extremely well when they were tucked in a dark corner of the courtyard under the balcony. Minimal light over in that spot. I moved them to the bench in the shade house a couple of years ago so I could take care of them better. They grew well but I’ve had crappy blooms since. Now I know! Back to the corner they go

[Clark711]

That's a bit cynical, undeserved for now.

Clark, the original poster, indeed is back.

---------- Post added at 01:43 PM ---------- Previous post was at 01:29 PM ----------

I definitely thank each of you for the good information you replied back. I learned a great deal.

First, I must admit that my readings are indeed Lux readings, not Lumens. I am using a Lux app (Light Meter Pro) on my iPhone. While I cannot state completely that it is totally accurate, its readings are very repeatable over several days and also very directionally correct.

I got a Lux reading of about 2500 from my south-facing window and a Lux reading of about 500 twenty feet across the room. Since it is a very open room with large windows the readings are reasonably consistent all day.

My phalaenopsis is now placed in that spot where it receives the 500 Lux for most of the day. Based on all this discussion, that may be too low.

Again, thanks much.

---------- Post added at 01:44 PM ---------- Previous post was at 01:43 PM ----------

I definitely thank each of you for the good information you replied back. I learned a great deal.

First, I must admit that my readings are indeed Lux readings, not Lumens. I am using a Lux app (Light Meter Pro) on my iPhone. While I cannot state completely that it is totally accurate, its readings are very repeatable over several days and also very directionally correct.

I got a Lux reading of about 2500 from my south-facing window and a Lux reading of about 500 twenty feet across the room. Since it is a very open room with large windows the readings are reasonably consistent all day.

My phalaenopsis is now placed in that spot where it receives the 500 Lux for most of the day. Based on all this discussion, that may be too low.

Again, thanks much.

[SouthPark]

I honestly admit that - while I do have a lux meter - and certainly most of us can readily purchase one from say an electronics store or ebay etc ------ I've never taken light measurements in my growing area before.

But I can certainly do that. In fact, I think I will do it, as having some quantities (eg. lux values) to share around can or will be useful.

In the past, we just basically have relative terms - such as 'low', 'medium', 'bright' ------ which don't necessarily mean a great deal when we think about it, as it's all relative and each person might have a different reference.

I agree about the condition of - orchid handling as much light as it can handle without getting damaged by heat - is probably best for growth performance - this isn't including nutrition in the plant and size of the plant, ambient temperature of growing area, air-movement etc yet. But as much a plant can handle should be based on current state of the plant (including all those aspects).

There will be uncertainties involved of course, such as just how much light for a particular plant. Some trial and error may be required - like start off medium, then build up (and knowing gradual build up allows time for hardening or toughening up, or something like that).

[Roberta]

Just to muddy the water a bit more... my own experience is that duration of light is also important. Early in my orchid growing "career" I tried growing Phals in my spare bedroom, which got about 4 hours of good morning light, then the sun shifted and light was very indirect. Plants grew, but didn't bloom. Adding a bank of the cheapest Home Depot fluorescent shop lights, on a timer 12 hours a day as a supplement got me nearly 80% reblooming. I don't have a clue what the actual light intensity was (never measured), not enough to cast sharp shadows... but the extra hours of light seems to have helped a lot. (I'm surprised that I never got raided, with that room aglow, visible from alley.)

[SouthPark]

That's true Roberta. Some plants are definitely noticed to have duration of light strongly correlating with flowering. Some plants - not necessarily orchids - may have some behaviour where blooming is triggered when duration actually gets less - relative to other times of the year. Or maybe even temperature changes etc.

I have one catt --- a Rlc. Memoria Helen Brown type of catt, that so far has 100% bloom probability (for the mature plant) - guaranteed bloom for each bulb. While I have other types of the same cross - but different cultivar - have different behaviours ----- not 100%. I'm sure other people have reliable flowering orchids too. It's just an interesting thing!