Ev to Lux to Foot Candle measurement

[DTB]

Hi all,

I am taking measurements with my Sekonic light meter as it is all I have and I found this table on their website.

Conversion Chart

Anyone of much greater knowledge see this as a fairly accurate conversion for working out orchid lighting power?
I am using LED grow lights both diffused and focused so I am taking different measurements from within the tank and at certain plants to try and adjust how much lighting I need.
I am using Andys Orchid website and a few other sources to see how many Foot Candle power I need for each plant and then measuring my lighting using an EV photographic light meter.
It not very scientific but given my resources, its the best I can come up with.
Any suggestions, ideas or recommendation on more accurately converting measurements?

[Ray]

Yes, that is a good chart, but there are two things to consider:

That meter is designed for photography, so is tuned to respond as the human eye perceives light, not as plants do - meaning it is particularly sensitive to the green wavelengths. If your LEDs are white, then it will give you reasonable readings. If they are red and blue, it's practically worthless.

Secondly, the recommendations for light level at Andy's, like most guides, are for the peak, noontime level to which they are to be exposed. For continuous, artificial lighting, the intensity should be approximately half of that.

[DTB]

Ray, once again, your advise has been invaluable. Many thanks.

Another peice of the puzzle falls in place.

I purchased 4 Ikea Plant LED grow lights this evening as an interim fix and placed them above the tank ( i have had some surprizing results with these recently) The light levels have risen to between half to 2/3s of the recommended levels based on the websites so based on your information i may be on the right track (although there are red Diodes on these so the reading may be out as you suggest)

Ill see how the tank responds over the next month.
Thanks for your help.

[Ray]

Originally Posted by DTB

Ill see how the tank responds over the next month.

In my opinion, THAT is the best thing to do - observe the plants closely. If you see reddening or bleaching, they're to close. If they get to be a darker green (a slower response), you might want to bring the lamps closer.

[MermaidNat]

This has been a very helpful thread for me as I figure out requirements for my new orchids. I currently have them under full-spectrum LEDs. Thanks!