Lumens for my new phalaenopsis

[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.