Artificial Lighting and Light Meters for Growing Plants

[CG100]

I bet other levels of secondary plant substances like aroma, vitamins etc are also affected by "less important" parts of the spectrum

The only major research has been into vegetative growth and flowering - by far and away the most important things commercially.

Although fairly recent investigations suggest that UV affects various chemical components in tomatoes.

In real life, apart from clandestine crops and vertical farming, the vast majority of horticultural lighting is additional to daylight - commercial horticulture on the grand scale could not make money otherwise.

[Bern]

I have a PAR meter (~US$150?) that I use to check lighting for the indoor bulbs[1]. Also, to verify outdoor lighting situations.

I do not use it at a level (accuracy, consistency, etc) to justify the price, but it does do the job in a handy package. What it does do is let me track and reproduce what individual species prefer or tolerate in my conditions. Interesting sometimes just how little light some forest floor plants want, compared to fall sun!

[1] Irresistible geophyte aroids that tolerate my (even indoors) cool tropical conditions.

Hi Robert. It's good to hear feedback from an actual user of a PAR meter.  I'm going to purchase one of these things as I've been convinced by Kelly's articles that it's a worthwhile gadget. I have a lux meter, but I don't want to mess around converting lux to PPFD.  Kelly uses the Apogee Full-Spectrum Quantum Sensor which cost her $500 in her 2021 article. What make and model do you have? Yours is quite a bit less expensive than Kelly's and it may be AOK for what I need it for.  I'm going to be growing a lot more of my plants under lights and I'm going to try to construct an ochidarium for some of the miniature Dendrobium and "leafless" orchids that need to be mounted to grow properly.  They need the right amount of light, temperature, and humidity and I don't want to kill a bunch of expensive plants guessing on their light requirements. Temperature and humidity are much easier to measure.

Did you have any success germinating JAA's Albuca unifoliata seeds?

[CG100]

Be very careful if looking at buying cheap PAR meters.
Many, perhaps most or all, are not.

I have trawled Amazon UK and some do not give PAR readings at all, despite what they claim (time and again, these have reviews that state that they do not measure PAR), and some require input of the source - daylight, HPS, LED etc. This being so, the meter is using some kind of "nominal source spectrum" to calculate numbers, in other words it is converting lux to PAR figures by calculation, it is not actually measuring PAR at all.

[Bern]

Be very careful if looking at buying cheap PAR meters.
Many, perhaps most or all, are not.

Caveat emptor! Let the buyer beware. Excellent advice.  Kelly uses the Apogee Full-Spectrum Quantum Sensor and I will take a close look at that one.  I think you also posted a link to one and I will take a look at it also.  Thanks!

[CG100]

I think you also posted a link to one and I will take a look at it also. 

Simple lux meter only - very cheap and lots of different cheap ones are available.

[Bern]

I can only find one - VERY expensive - a Hortipower PG200N.

Only $3388.00!

https://gamma-sci.com/product/pg200n-handheld-par-meter/

[Bern]

Apogee Full-Spectrum Quantum Sensor

A steal at $532.00

https://www.apogeeinstruments.com/quantum/

Probably the best available at the price. 

[Bern]

I wish someone had told me that when I was 16 and doing A level Physics - a mole of football supporters would have been a very enlightening concept.

Think really big - how about an Avogadro's number (mol) in gold krugerrands!

[CG100]

PAR meters - the problem will be sales volume, I suspect.

The demand for simple lux meters will be trully vast, especially if cheap - many people who own or are responsible for indoor public or work spaces will have need of one at some stage.

[David Pilling]

Think really big - how about an Avogadro's number (mol) in gold krugerrands!

All the gold in the world 244 000 metric tonnes. One Krugerrand 33.9 gm. Max possible Krugerrands 7 197 640 117 - nowhere near a molesworth of them.

[Bern]

All the gold in the world 244 000 metric tonnes. One Krugerrand 33.9 gm. Max possible Krugerrands 7 197 640 117 - nowhere near a molesworth of them.

Think really BIG - like Star Trek Big!  Is there enough gold in the solar system perhaps?

[David Pilling]

Is there enough gold in the solar system perhaps?

"
there is gold in the sun. The sun is a "metal rich" Type I star (that's "rich" by star standards, about 2% of atoms that are neither hydrogen nor helium).

the abundance of gold is about .3 parts per trillion. That comes to about 10^20 kilograms of gold.
"

I'll give you that the Sun contains a mole of Krugerrands - now how do we get hold of them.

[Bern]

I'll give you that the Sun contains a mole of Krugerrands - now how do we get hold of them.

We will have to use the Dan Quayle method.  The joke going around NASA when Vice President Quayle was the Chairman of the National Space Council was that he wanted NASA to have a mission that would outdo the Apollo program. So he decided that NASA would commence planning for a manned mission to the Sun. When asked how this would be possible given the extreme temperatures there, Dan replied - "I've already figured that out, we're going to go at night."

So, how about gold mining on the sun at night?  Dan would be happy.

[Bern]

Apogee Full-Spectrum Quantum Sensor

A steal at $532.00

https://www.apogeeinstruments.com/quantum/

Probably the best available at the price. 

Phantom (Hydrofarm) sells their PAR meter as the PHOTOBIO Advanced Quantum PAR Meter.  However, I suspect, but cannot prove, that this unit is lux meter that converts lux to PAR. And the reason is that the sensor on the unit looks just like the sensor on my lux meter.  It looks nothing like the Apogee sensor.  However, at $150.00, it may be good enough for what I want or need to do.

The Apogee meter has a few additional items that I'd just have to have - a telescopic sensor wand, a communication cable for a computer hookup, and a nice carrying case that would add an additional $180.00. 

But, I'm sure that the Apogee sensor is a true quantum PAR sensor.  The Phantom, Photobio, Hydrofarm, or whatever name they are calling themselves now, may not have a true PAR sensor.  More research will be required.

But, Hydrofarm is a reputable company with a long history and their LED lighting products are very widely used.

https://www.phantombio.com/products/controllers/product/photobio-advanced-quantum-par-meter

https://www.phantombio.com/about-us

https://www.amazon.com/PHOTOBIO-LGBQM2-Advanced-Quantum-Micromols/dp/B08HPGLZHL?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=ARU9XTG9WELO3

What do you think? Is the PHOTOBIO sensor a true PAR sensor?