Clarification for Phalaenopsis Shade Requirements
 

I have read various things online about the light requirements for Phalaenopsis. One place I read they need as much as 75-80% shade. I read elsewhere that they thrive in 3 or 4 hours at 60%, and therefore 70% is suitable all day. I also seem to recall a difference between requirements for Novelty species and perhaps other species. I'd like to get some clarification :thanx:

Oh and one more thing. Suppose I keep my Phals the whole day in 60%, and that would be too much. Could I add, just for them (and other low light Orchids), a simple window screen, something along those lines, or anything specified to shade about 10% more?

Percent shade that is desirable depends on light intensity. This varies a lot depending on how far North somebody lives. My observation has been midsummer sun in northern Germany is about as intense as my winter sun. Plants I need to grow in mostly shade can grow in full sun in Germany.

So people tend to measure light intensity to compare light. Most hybrid Phals grow and flower best at 1,000 foot candles of light, 10-12 hours a day, with a late fall-early winter bump to 1,200 foot candles for 6 weeks to help with flowering.

Foot candle is a US measurement. It equals 1 lumen per square foot. The SI unit is the lux; 1 foot candle = 10.7 lux. So 1,000 foot candles = 10,700 lux.

If you're serious get a light meter. You can probably find an old photographic light meter at a used camera shop. You can also find instructions online to use an autofocus single-lens reflex camera (SLR) to calculate foot candles.

Phone light meter apps don't work unless the app was written for the specific "camera chip" (CCD, charge capture device) and version of operating system in the phone.

Phal. pulcherrima used to be called Doritis pulcherrima. Unlike other Phals it grows in full sun on rocks. Hybrids with this ancestry can tolerate a lot more light, but don't need it.

Hold your hand between the light source and the plant. If you see a very indistinct shadow that is probably fine for Phals.

Photone is a good app. You do have to pay to unlock some light sources, but it seems very accurate. The app has been calibrated for many of the popular phone brands/models. I tested it against a quantum spectrometer, and the PAR values given by the app were within 10% of the high end meter. The app developers do note that accuracy on androids can't be guaranteed due to the sheer number of models that exist (but I expect that common ones, and iPhones, should work fine).

I have this analogue light meter. It works well.

There are a lot of used photographic light meters available on eBay. Search on
PHOTOGRAPHIC+LIGHT+METER

Many work on the photoelectric principle. The more photons striking a silicon semiconductor target the more electricity generated, which is translated to light flux. The smaller ones don't need batteries; they operate on the electricity generated from light striking the device.

An engineer friend found some used Gossen Panalux professional light meters on eBay a few years back for $20. You can point this one at the sun without damage.

Attachment 158791

This was a $3,000 instrument when new. You can still buy one but they're a little more than $20 now. Search eBay for GOSSEN+PANLUX+ELECTRONIC+LUXMETER

Every phalaenopsis I have ever owned grew and bloomed better in deep shade than they ever did under brighter conditions, but don’t expect an immediate improvement.

When you change the growing conditions of a plant, it takes it a while to adjust and get back into its normal growth and blooming routine. I have seen vandas, moved from a greenhouse to window environment, take a year off, then resume blooming for the grower.

I just downloaded Photone to try to figure out how much light I am getting in certain rooms. Do you know how much the readings vary between incandescent (free), LED and sunlight? Grossly inaccurate? Kinda close. If it is kinda close it probably would be good enough for my needs at the moment...