How far to put orchids from grow lights

[mizutsune]

We get very few sunny days where I live, so I decided to try grow lights. I haven't used them before and admittedly should've done more research first, but this is what I purchased: https://www.amazon.com/dp/B09Z1X26S8

I got it set up and the lights seem very bright. I'm worried about them burning my orchids. Not sure if I'm overreacting.

I'm wondering what distance I should put my orchids from the lights? I currently have phalaenopsis, cattleya, oncidium, and neofinetia falcata orchids.

Thanks!

[estación seca]

Welcome to the Orchid Board!

The lamps appear to be made by Barrina. I recall people here discussing this brand here on Orchid Board recently. I suggest you use the Search function in the top maroon menu with that name. If it doesn't work on your phone click Advanced Search.

[2009zohsix]

This is a good read
https://herebutnot.com/light-recomme...d-houseplants/

There is also a iPhone app to measure PPFD, named PHOTON. Not sure of it's accuracy compared to a dedicated LED light meter but it's a start.

[camille1585]

Originally Posted by 2009zohsix

This is a good read
https://herebutnot.com/light-recomme...d-houseplants/

There is also a iPhone app to measure PPFD, named PHOTON. Not sure of it's accuracy compared to a dedicated LED light meter but it's a start.

I have tested the app against calibrated, professional equipment and it comes within 15% of those values. When measuring umol/m2/sec, around 10% deviation, even between high end calibrated devices, is considered acceptable. So based on my test, with an iphone and android, and with burple light, the app seems rather reliable. According to the info on amazon, at 8in you should measure 451 μmol/m2/sec and 225μmol at 12in so you could compare the app readings to that.

As to the distance to the plants, what sort of orchids do you have? LEDS don't cause burns as easily since they give off little heat compared to older technology. However, excessive pigmentation or yellowing is a good sign the light is too much for the plant.

You can use the μmol/m2/sec ranges provided in the link above (herebutnot) to get some ballpark figures, and then adjust based on how the plants react.


Here is an older thread I dug up about Barrina lights, I only had a quick glance at the contents so don't know how relevant it is to you.

Anyone use Barrina or Monios LED lights? - Orchid Board - Most Complete Orchid Forum on the web !

[2009zohsix]

Originally Posted by camille1585

I have tested the app against calibrated, professional equipment and it comes within 15% of those values. When measuring umol/m2/sec, around 10% deviation, even between high end calibrated devices, is considered acceptable. So based on my test, with an iphone and android, and with burple light, the app seems rather reliable. According to the info on amazon, at 8in you should measure 451 μmol/m2/sec and 225μmol at 12in so you could compare the app readings to that. [/url]

Thanks Camille! That information regarding the accuracy is great to know. I've been using the app without knowing the accuracy, based on my "crooked stick" theory of relative measurement.

I have a Spider Farmer sf1000 led panel ordered to test the output for Cattleya, and separately for Phalaenopsis. Hopefully the dimmer works well enough to use these panels for different light requirements.

[camille1585]

Originally Posted by 2009zohsix

Thanks Camille! That information regarding the accuracy is great to know. I've been using the app without knowing the accuracy, based on my "crooked stick" theory of relative measurement.

I have a Spider Farmer sf1000 led panel ordered to test the output for Cattleya, and separately for Phalaenopsis. Hopefully the dimmer works well enough to use these panels for different light requirements.

The accuracy is going to depend a lot on your phone model. Photon has 'calibrated' a lot of the most popular phone models, so those are likely fairly accurate.

[mizutsune]

Thanks for the advice! I used the Photone app and the readings were pretty accurate to the μmol/m2/sec ranges shown on the Amazon listing.

It seems these lights may be too bright for my orchids at the distance I currently have them. According to a chart I found online it says phals should be getting between 40-80μmol. Is this accurate? I had to disconnect all of the lights except for 1 and have it about 2 feet above my orchids to reach a reading of ~160μmol. Do you think my phals can tolerate this amount of light?

I will try keeping the light on for shorter periods at first to see how my orchids react, but I'm considering purchasing lower watt lights. With these lights, I'm unable to use each shelf on the rack, the brightness seems too high especially for the upper shelves that are closer to the lights.

[estación seca]

Phal. growers recommend 1,000 foot candles of natural light. That is about 150 μmol/m2/sec of natural light.

[camille1585]

Originally Posted by mizutsune

Thanks for the advice! I used the Photone app and the readings were pretty accurate to the μmol/m2/sec ranges shown on the Amazon listing.

It seems these lights may be too bright for my orchids at the distance I currently have them. According to a chart I found online it says phals should be getting between 40-80μmol. Is this accurate? I had to disconnect all of the lights except for 1 and have it about 2 feet above my orchids to reach a reading of ~160μmol. Do you think my phals can tolerate this amount of light?

I will try keeping the light on for shorter periods at first to see how my orchids react, but I'm considering purchasing lower watt lights. With these lights, I'm unable to use each shelf on the rack, the brightness seems too high especially for the upper shelves that are closer to the lights.

160μmol is at the higher end of the range but still ok. My shelf height can't be changed so I went from 12 to 9h with mine, since in combination with the natural light they get it was too much for the Phals. That did the trick in my case.

Another option is to place some taller/larger orchids with high light requirements on the shelves and nestle the Phals under/between them so they get some shade.