Amount of light?

[Death The Cultivator]

Do you have some meter recommendations?

PHOTOBIO LGBQM2 Advanced Quantum PAR Meter (Micromols) https://a.co/d/5QXh1Z7

This one is fairly good with accuracy pretty close to Apogee. Price is right for the budget grower.

USB Smart Quantum SQ-420X PAR Sensor

PAR (photosynthetic active radiation) is the easiest way to measure the available light for corals consume and use for photosynthesis. With LED lights giving more and more control to the consumer the best thing is a PAR meter that is affordable and simple to use. With PAR readings you can...

www.bulkreefsupply.com

If you have a computer this is my preferred choice because I trust the accuracy using it for commercial and personal.

Pulse Pro

The Pulse Pro offers enhanced grow room monitoring with CO2, PPFD/PAR, light spectrum, vapor pressure deficit, temperature, and humidity tracking. This advanced monitor boasts real-time and historical data, customizable alerts, and support for multiple sensors and WiFi networks. Crafted in the...

pulsegrow.com

This is the goat because it does PAR and VPD while logging data.

 

[Delps8]

It's why I hate the apps and advocate for a PAR meter. If we were working with low DLI, sub 25, I believe they could work well for the most part even with an iPhone - mostly.

Come to think of it, I might have picked up on that. ;-)

One of the reasons I'm more inclined to use Photone is that I'm a programmer so I understand what Photone is trying to do. OTOH, I LOL when I see TV-like BS when they zoom in on a picture and "the software enhancement" comes up with a picture of the bad guy. Sorry, at some point you just can't get there from here.

When I was building lights, a PAR meter was instrumental after I discovered that my phone was inadequate even compared to a regular lux meter(still sucks). Above 600umols(I doubt that much in some cases) can't even be read, not particular trusting of apps at that point.

I checked my Apogee using this page and my meter is reading 2.4% high. I ran Photone at the same time and, it never settled down enough to get a reading. Having said that, those readings are "off the charts" because there's no reason why I'd use a PAR meter to get the PPFD of the sun. However, it does point to a limitation of the technology, as you've stated.

 

[Death The Cultivator]

Come to think of it, I might have picked up on that. ;-)

One of the reasons I'm more inclined to use Photone is that I'm a programmer so I understand what Photone is trying to do. OTOH, I LOL when I see TV-like BS when they zoom in on a picture and "the software enhancement" comes up with a picture of the bad guy. Sorry, at some point you just can't get there from here.


I checked my Apogee using this page and my meter is reading 2.4% high. I ran Photone at the same time and, it never settled down enough to get a reading. Having said that, those readings are "off the charts" because there's no reason why I'd use a PAR meter to get the PPFD of the sun. However, it does point to a limitation of the technology, as you've stated.

Fair lol. I'm technical by nature so I am inadvertently abrasive when I don't mean to be.

I appreciate what they are trying to do but it is misguided and misleading for growers who aren't initiated into the boring awesomeness of horticultural lighting.

My wife has used the Apogee to figure out the best places for her house plants. I've seen them used in greenhouses to get average DLI throughout the season.

That curved dome on the Apogee is part of how the accuracy occurs compared to the flat surface of a phone.

 

[Delps8]

Fair lol. I'm technical by nature so I am inadvertently abrasive when I don't mean to be.

No problem with that. I have to "curb my enthusiasm" quite a bit, as well.

I appreciate what they are trying to do but it is misguided and misleading for growers who aren't initiated into the boring awesomeness of horticultural lighting.

Er, ah, well, yeh, but… There's always a "but", right? They're getting growers in the ballpark for PPFD at a low price point and they're getting growers thinking about lighting. Lemme toss this out at you - think of how many thousands of pages to HTML there are about nutrients (which is just different ways of mixing up a small number of chemicals none of which will make a marked improvement in yield) vs thinking about the biggest driver of growth, that being light. Nutes have been all the rage for years but there's only a tiny fraction of that attention paid to providing food for the plant.

My wife has used the Apogee to figure out the best places for her house plants. I've seen them used in greenhouses to get average DLI throughout the season.

It's in the family, then. Great. My POSSLQ smokes more than me but complains about leaving the car outside to keep temps down. Oy.

That curved dome on the Apogee is part of how the accuracy occurs compared to the flat surface of a phone.

Bingo! A 1" optimized sensor vs a peep hole.

 

[Delps8]

PHOTOBIO LGBQM2 Advanced Quantum PAR Meter (Micromols) https://a.co/d/5QXh1Z7

This one is fairly good with accuracy pretty close to Apogee. Price is right for the budget grower.

USB Smart Quantum SQ-420X PAR Sensor

PAR (photosynthetic active radiation) is the easiest way to measure the available light for corals consume and use for photosynthesis. With LED lights giving more and more control to the consumer the best thing is a PAR meter that is affordable and simple to use. With PAR readings you can...

www.bulkreefsupply.com

If you have a computer this is my preferred choice because I trust the accuracy using it for commercial and personal.

Pulse Pro

The Pulse Pro offers enhanced grow room monitoring with CO2, PPFD/PAR, light spectrum, vapor pressure deficit, temperature, and humidity tracking. This advanced monitor boasts real-time and historical data, customizable alerts, and support for multiple sensors and WiFi networks. Crafted in the...

pulsegrow.com

This is the goat because it does PAR and VPD while logging data.

I'd be leery of the LGBQM2. When I was looking to get a PAR meter early last year, build quality and support were issues for me so I tithed to Dr. Bruce. Just a few weeks ago, I came across this page. It is a lot cheaper than an Apogee but you get what you pay for. I really like using the wand on the Apogee, too.

One product that checks a lot of the boxes for me is the SPOT ON. No idea about its accuracy 40% less than an Apogee, it appears to have a real company behind it, and Shane at Migro is repping, so there's that.

 

[Talonxracer]

PHOTOBIO LGBQM2 Advanced Quantum PAR Meter (Micromols) https://a.co/d/5QXh1Z7

This one is fairly good with accuracy pretty close to Apogee. Price is right for the budget grower.

USB Smart Quantum SQ-420X PAR Sensor

PAR (photosynthetic active radiation) is the easiest way to measure the available light for corals consume and use for photosynthesis. With LED lights giving more and more control to the consumer the best thing is a PAR meter that is affordable and simple to use. With PAR readings you can...

www.bulkreefsupply.com

If you have a computer this is my preferred choice because I trust the accuracy using it for commercial and personal.

Pulse Pro

The Pulse Pro offers enhanced grow room monitoring with CO2, PPFD/PAR, light spectrum, vapor pressure deficit, temperature, and humidity tracking. This advanced monitor boasts real-time and historical data, customizable alerts, and support for multiple sensors and WiFi networks. Crafted in the...

pulsegrow.com

This is the goat because it does PAR and VPD while logging data.

I use the Photobio PAR meter and it works great plus like you said it is a little easier on the wallet.

 

[Delps8]

I use the Photobio PAR meter and it works great plus like you said it is a little easier on the wallet.

No question about that!

 

[Butrod]

Hey, I'm trying to understand the logic behind DLI. In theory it should get bigger as long as the plant ages and gets bigger in size, or the opposite a tiny plant can only do a bit of growth over the length of a day. What if someone vegs a 3m tall plant in a hall, wouldn't that justify to cross top PPFD levels to max so that the middle parts have a better chance to get more light?

 

[Talonxracer]

Sure you can up the lights intensity to reach deeper into the plant. But the upper portions of the plant can incur light stress because they are getting to much excessive light. The DLI is more of a starting point(some plants want a little more, some less), the DLI is how much light the plant can use in photosynthesis, bigger does not change the amount of light the plant receives at individual leaves . The extra light beyond what the plants leaves can consume becomes heat, too much heat and you get stress. So up the intensity in steps and watch for negative results from the plant.

Personally I would do some defoliation, lst, etc along with adding fill lights to boost what the lower portions get.

 

[Delps8]

Hey, I'm trying to understand the logic behind DLI. In theory it should get bigger as long as the plant ages and gets bigger in size, or the opposite a tiny plant can only do a bit of growth over the length of a day. What if someone vegs a 3m tall plant in a hall, wouldn't that justify to cross top PPFD levels to max so that the middle parts have a better chance to get more light?

DLI is the amount of photons hitting a given area in 24 hours. By implication, it's also the amount of photons hitting, say, a plant leaf. I'd argue that the size of the plant is not germane, rather it's the size and maturity of the leaf that drives its ability to process the photons that are hitting it.

"so that the middle parts have a better chance to get more light" - the only way to get light to the middle of a plant is to remove the leaves between the light source and the middle of the plant. A given cannabis leaf will absorb the vast majority of the photons hitting the surface.

If you measure the PAR at the surface of a cannabis leaf and then measure the PAR directly below the leaf, the reading below the leaf will be a tiny fraction of the reading that was taken above the leaf. I checked into this a few months ago and, even though the leaf was narrower than the 1" sensor on the Apogee, the reading below that leaf was below the light accommodation point, meaning is the amount of light needed to be a net photosynthetic contributor to the plant (63 µmols in cannabis)

No surprising when you come to think of it — forests are dark, right?