I am not up on the current lux lights etc, the only lights I have ever had are the "shop lights" with the plain old fashioned cheap flourescent bulbs. I am using one (and only one 4 footer) as we speak.

Having said that,,,,unless I missed something in your post, are you paying attention not so much to the actual light fixture,,, but how far above the top of the plants it is placed?

For example, as you stated, Optimaras may not require so much light, so they would go to the far end of the tubes etc. Darker or red type leaves can use a lot of light. So they could be more in the middle or closer to the tubes.

Call it ignorance on my part but I don't get involved in numbers. I am lucky to have one 4 foot shop light with cheap bulbs, about 15in above the top of my plants only on the one shelf which is near the floor. I have to make the plants work with the light. There is no adjusting the lights for the plants.

I have read many posts about violets/gesneriads under lights and like you I am very confused. So I simplified it out of necessity. Suit the plants to the lights (in my world). If a plant is not doing well, doesn't matter that the books tell me to use,,,,,I swap the plant out for another that could use a little more light. Or vice versa.

I know none of this will help you. May only confuse you more. Just wanted to let you know that some of us jockey between window and fixture. For the most part, it does work for me, but remember,,,,,I am not selling plants or showing them. Perfection is not my goal only because it can't be. I do what I do just to enjoy having the plants. Hope you figure it out for yourself. Rosie

Rosie -

Your logic is correct. Same light level can be achieved by a weak light close to the plants or strong light further above.

The measurement is is done on the level of the leaves - so it is what plants get. (That's the difference between lux and lumen - the brightness of the light source is measured in lumens - that's what is written on a box, and lux is actually how much light hits a unit of surface - and it depends on the distance. )

If you want to participate in this experiment - you probably have an android phone - or somebody in a family has an android phone. Ask the younger generation to download a free App "lightmeter" - and you have your equipment ready. I bet your inexpensive 2 or 4 foot shoplight is NOT even close to delivering 1100 lux on a level of your leaves.

Thing is - we can use or not use the lightmeter - but growers with experience do not look the shade from the hand - they look at the plants - and the plants tell them - if it s not enough or too much.

i.

Thank you Irina, Wow, you are gonna faint when I admit this, but I don't use the "hand" light measurement either. The plant either does well, or doesn't. Then it doesn't get moved or it does. I know,,,,but I guess I kind of know my window light (after 30 years of living here I should!!!!) and instinct takes over and well,,,,,. Actually I have pretty good luck, just run out of actual room now and then! Not really a cure for that! lol Rosie

PS. Aren't androids those cute little robots on tv?

Yup they are.

Since I already earned a senior discount in some restaurants... that's my take...

3 types of cell phones -

I-phone - based on the Mac operational system - the Apple one - you now - red Macintosh apple with a bite... Steve Jobs..

Based on quasi-Window operational system - androids or smartphones - most popular are Samsung Galaxy - the last one is Galaxy C8 - that has the best camera... tada, tada, tada.. costs more than a mortgage payment...

And Old People Phones - WITH BIG BUTTONS.

ROFLMBO!!!! And then there is MY dinosaur!!! Get a call, make a call, get a text, make a text!!!!! Pix are not worth a tinker's darn,,,,no data. After all THAT is what computers are for!

If I leave the house without my phone it doesn't bother me a bit! Rosie the oldster!

PS. And I get my choice of discount! Senior OR Military!!!! Love it!!!!

Get outta Dodge! Ok. Got some more stuff to research.

Aye aye Captain Rosey! Phones are ok for photos, but it doesn't match a REAL camera.

You are absolutely RIGHT! That is what my 35mm with 3 different lenses are for!!! Now if I could only remember to take the pix! lol

Hey Jeff,,,,,don't make it hard. Let the violets talk and more important,,, listen. The light thing is a lot of intuition. Have you read the posts where someone has said "I have two violets and one is happy growing according to Hoyle, but that other one,,,,Oye!" ???? No two are alike even if they are the same variety sometimes. Just start moving them around and they will finally settle down with light. You will never have enough light options for everyone! Just my opinion. Rosie

Sure, thanks Rosie. I really enjoy some of the more technical aspects of raising AVs. In the course of "learning" I discovered an error in what I thought I knew about recommended artificial light levels.

I was concerned as to why there was such a wide disparity in the lux numbers listed as optimal amongst some pretty experienced sources.

Light meters will never replace "paying attention", but I really like my toys!

I got my answers here as usual! Thanks to all!