Do you measure PAR for your grows ?

[stickyunderwear]

I found a ebay deal last summer on a Apogee MQ-500 and have been trying to put it to use measuring light levels for plants. I find that a PAR of about 125-150 does well for starting cuts under a dome. Its also a HLG QB-96 4K same as mom box.

My bonsai moms in 5" square pots in my mom area is 12" deep by 36" and a overall height of 26" lined with reflective material. The light is a HLG QB-96 (3"x24") on a dimmable Meanwell driver. About 10-12" from light where the top of the moms get before I trim them back the PAR is around 300 dead in the middle of the light and tapers down to 100+ moving to the end of the cabinet. This seems to work well for the moms since I really dont want them to grow very fast and Im going to lower it some to keep them going but hope to just keep them healthy but not growing too fast. I have 9 strains of bonsai moms.
My main light is a few years old Cree 3590 cob kit from Timber Grow lights. 12" below light in the middle of the fixture the reading with the Apogee reads 1250 on full power. I have a red supplemental kit I put together of 660 Cree chips (small ones) and that will boost it up to 1350. I turn on the additional 660 reds when I flip to flower and usually turn the main light down a smidge.
Some plants like all the light I can give but I have recently started a grow of Ice Cream Cake that I had to turn the light down. Have not measured it yet waiting to see if the plants like that level.
Im interested if more people are taking readings and trying to make use of the info. I understand all lights will give different readings but I would imagine they are similar for the most part.

 

[CrustyCruz]

Par, lux, umol, tried learning about this stuff when I bought leds and bleached some plants.. Then I hear leds are different? Meters don't read them right?

Screw it, I'll check back in 20 years when the truth is canonized. Maybe Jorge can pen a new work by then.

 

[flylowgethigh]

That 500 does not cover the 400-700 spectrum as well as their 520, especially at the higher red freqs.

https://www.apogeeinstruments.com/s...t-quantum-sensor-usb/#product-tab-description

But with the same light, any meter can be used to measure the power at the plant tops, and use that reading to adjust from. I believe CO2 and leaf temperature are also important factors in light control. The USB 520 is a nice item.

 

[Fitzera]

I think the best way to go about it is to disregard the numbers at first when comparing to what you read in articles or grow logs, etc(aside from getting a starting point). Try to set the light to where the plants look exceptionally happy. Then take your readings at that point and work with those. As in, each meter will read the intensity differently, so find what reading yours gives when the plants look the best.

I fell victim to pushing the intensity and the plants weren't happy. While I am now using some charts as reference ranges in conjunction with a meter, ultimately it's the plants that will decide if it is too much or too little.

Like flylow stated, higher to excessive light intensity will require co2 supplementation. Vpd (leaf temp/humidity) will also have a great effect on growth and overall wellbeing.

 

[stickyunderwear]

Par, lux, umol, tried learning about this stuff when I bought leds and bleached some plants.. Then I hear leds are different? Meters don't read them right?

Screw it, I'll check back in 20 years when the truth is canonized. Maybe Jorge can pen a new work by then.

Thanks for contributing something useful.

 

[stickyunderwear]

I think the best way to go about it is to disregard the numbers at first when comparing to what you read in articles or grow logs, etc(aside from getting a starting point). Try to set the light to where the plants look exceptionally happy. Then take your readings at that point and work with those. As in, each meter will read the intensity differently, so find what reading yours gives when the plants look the best.

I fell victim to pushing the intensity and the plants weren't happy. While I am now using some charts as reference ranges in conjunction with a meter, ultimately it's the plants that will decide if it is too much or too little.

Like flylow stated, higher to excessive light intensity will require co2 supplementation. Vpd (leaf temp/humidity) will also have a great effect on growth and overall wellbeing.

Can you elaborate on the charts you use ?

 

[Ibechillin]

I was listening to a podcast from KIS organics last night with Bruce Bugbee. He was saying that light bleaching only occurs when red light comprises more than 60% of the 400-700nm "PAR" spectrum...Also experiments/publications of inclusion of IR alongside PAR in relation to growth seem non existent currently.

~5 years ago using basic 80cri 3000k citizen and cree cob chips with minimal IR at 1 light per sq ft around 800ma people were obtaining yields in the 2 gram per watt range by maximizing diffusion with between 500 and 600ppfd across entire canopy without additional CO2.

Double ended 1000w HPS on 5 ft spacing 4ft above canopy will create 1000PPFD across each 5x5 footprint beneath each light, and the HPS produces ~60% of its spectrum in unusable IR beyond 700nm (according to publications from Gavita) and minimal useable PAR in the 430nm and 662nm Chlorophyl A peaks.

I experimented with planting germinated seeds into soil outdoors and sprouted them under the max intensity of the sun (2000 PPFD) beginning of 2019. Did this after reading publications on photomorphegensis discussing benefits of starting and finishing plants under the same spectrum and intensity for max productivity. Has me scratching my head on how much and what ratio of spectrum plants can tolerate.

 

[stickyunderwear]

That 500 does not cover the 400-700 spectrum as well as their 520, especially at the higher red freqs.

https://www.apogeeinstruments.com/s...t-quantum-sensor-usb/#product-tab-description

But with the same light, any meter can be used to measure the power at the plant tops, and use that reading to adjust from. I believe CO2 and leaf temperature are also important factors in light control. The USB 520 is a nice item.

So do you use the 520? Im not using any kind of CO2 as I believe most average growers do not as well. Cant seal the closet up and keep bottles around easily. In the winter keeping humidity up is a problem and Im using humidifiers to keep my levels up within reason where I live. Upper 30's to 40% for the moment considering the ambient winter humidity in most homes is in the teens to twenties this time of year. VPD is something I have looked at over the years I have been growing but so long as the humidity levels are in reasonable ranges and lean a tad to the humid side its not a biggie it seems to me.

 

[stickyunderwear]

I was listening to a podcast from KIS organics last night with Bruce Bugbee. He was saying that light bleaching only occurs when red light comprises more than 60% of the 400-700nm "PAR" spectrum...Also experiments/publications of inclusion of IR alongside PAR in relation to growth seem non existent currently.

~5 years ago using basic 80cri 3000k citizen and cree cob chips with 1 light per sq ft around 800ma people were obtaining yields in the 2 gram per watt range by maximizing diffusion with between 500 and 600ppfd across entire canopy.

I would like to find a reasonably priced spectrometer to see what I have when I plug in the 660 add ons I use for flower. Bought them as a kit from Rapid LED along with a 730 kit for end of light cycle. They dont sell the kits anymore.

I tried a couple of the cheap DIY spectrum kits with the available online software but the results were pretty less than crappy.
This issue is more of a thing I am just an curious about since common sense guides me to roll back the light especially the last couple weeks of flower.
My inner nerd just wants to try and find some data using my meter to have some baselines for future grows for some of the strains I have.
This is a new account for me since I had stopped visiting here for a while and couldn't locate my old info. Been growing for a number of years. Less than a decade but more than a few.

I have listened to and watched all I can from Bugbee and those grow chambers they have are the shit. Im not out to argue the minutia but try to use some of the info he shares in a general way.

 

[St. Phatty]

The plant itself is a great PAR meter.

 

[f-e]

The plant itself is a great PAR meter.

Yes, the internet can say whatever it likes. It's my plants I'm listening to. We can overlay charts all day long and find them telling different stories. There is not much in terms of the baseline figures a newbie is going to search for. Nothing that can take into account the vast number of variables. I use the cheapest of lux meters as all I need are some numbers to aid repeatability. However it's nice I can do some simple math to get a ppfd number. Aiding me to compare my results to other peoples. However there is never a guarantee somebodies figures are accurate. Buying a meter doesn't mean you can use one. Some of the very best still need the reading correcting by 50% before you get close to the truth. So you may as well just use the $10 one and do the math on that.

 

[Fitzera]

Can you elaborate on the charts you use ?

I didn't save any links, I just Google umol/s/m2 for cannabis growth and went through a bunch of different articles to get a rough idea of the plants needs in different stages. Then I used the information that ".............." posted in my thread and started putting it all together in regard to what I'm seeing in my tent.


Edit: I take that back, I did save one chart. In this chart I basically just referenced the ranges given for stages of growth.

 

[flylowgethigh]

So do you use the 520? Im not using any kind of CO2 as I believe most average growers do not as well. Cant seal the closet up and keep bottles around easily. In the winter keeping humidity up is a problem and Im using humidifiers to keep my levels up within reason where I live. Upper 30's to 40% for the moment considering the ambient winter humidity in most homes is in the teens to twenties this time of year. VPD is something I have looked at over the years I have been growing but so long as the humidity levels are in reasonable ranges and lean a tad to the humid side its not a biggie it seems to me.

No, I have a photobio. I like the 520, especially how it can be plugged into a computer, but not $400 worth of liking. I agree, and I'm in the camp that the plants are the decider on required light power. But it is nice knowing what that number is. My tallest plants are at 340 umols now, since they have grown toward the light. They have more roots, and can take the increased power now. Here is a pic of my "rabbit", a plant that popped 4 days before I planted the dawg pack. It was probably getting too much energy when it was smaller, and didn't have enough root to process it. Seems happy now.

And I may be 100% wrong BTW. That may also be too small a cup, or likely too much supplements too early. Because it's first, the rabbit is the guinnie pig.

 

[big315smooth]

i have a few times and still dont know what the numbers mean

 

[stickyunderwear]

That 500 does not cover the 400-700 spectrum as well as their 520, especially at the higher red freqs.

https://www.apogeeinstruments.com/s...t-quantum-sensor-usb/#product-tab-description

But with the same light, any meter can be used to measure the power at the plant tops, and use that reading to adjust from. I believe CO2 and leaf temperature are also important factors in light control. The USB 520 is a nice item.

I kind of was scratching my head over this and I went back to look. Especially since this was an upgrade for an older version for me.

I compared the 500 to your supposed better 520. Dude they use the exact same sensor and the specs are the same. The 500 IS a full spectrum. The only diff is one is plugged in via USB to a laptop or desktop and the 500 is self contained. The difference is a correction factor for using UNDER WATER I dont know about you but I dont grow plants underwater.






From the Apogee website.



Apogee quantum sensor are calibrated to make absolute PPFD measurements in air. The waterproof sensors can be used to make absolute PPFD measurements underwater by applying an immersion effect correction factor, the SQ-420, SQ-520, MQ-210, and MQ-510 already apply the correction factor. For details on making underwater measurements, please refer to Underwater PAR Measurements.
Kind of puts a dent any any words from you. Sorry.

 

[Dr.King]

Greetings all, someone posted a good link about a app called Lux for your phone that you can use to tell how much your lights are putting off. That seemed pretty usefully to me. Just found out last run my SP2000 was hitting 60k-80k lux at some spots in my tent at 8-10 inches away from the top colas and colas weren't even bleached yet. Goes to show you just a phone app can help you out some. I was having my leafs turn yellow so fast even me tripling my cal/mag wasn't even helping which normally does the trick. The thread which I saw the lux app said you only need 30-40k max which is what the sun does on the brightest day outside. Happy growing all.

 

[Ibechillin]

The sun at noon on a clear day will produce as much as 130,000 lux or 2000 PPFD and wont cause light bleaching due to the high ratio of blue light (approximately 1:1) but very likely is surpassing the photosaturation threshold of the upper chloroplasts. The lighting thread in my signature has charts showing DLI outdoors from full spectrum sunlight in the San Francisco bay area from March through August, more than 60DLI accumlated somedays. Bruce Bugbee mentioned in his lighting myths video cannabis can utilize more than 43.2 DLI typically regarded as most productive but spectral ratios have major influence on plant utilization. (I cant wait to experiment more with 14 hour on 10 hour off flowering by utilizing 730nm at lights off for increased DLI under different lighting types/spectrums).

500 ppfd under 3500k led with minimal IR is roughly 30k lux and with adequate overhead diffusion to reach deeper into the canopy (or additional side lighting/under canopy lighting to stimulate lower leaf chloroplasts) people have claimed 2gpw. This is also approaching the "theoretical" max ppfd plants can tolerate at atmospheric ~400ppm CO2 availability.

An HLG 600 rspec hung 36" over a 5x5 space will spread 500 ppfd to each corner and close to 775 ppd in the direct center below the fixture.

 

[Dr.King]

Greetings Ibechillin, I can claim to hit 3 lbs with just 400 watts of light myself. Happy growing .

 

[flylowgethigh]

From the apogee website. You have a 500 (old), they now sell 520s.

I like the USB version so I can use their logger SW and display on a flat screen. I ideally would have one in each tent, mounted on a cross-brace I cn adjust the height on, so I can set the lights from the control closet without having to go in and out of the tent.

That 500 will work just fine to measure the power output at the height you have the lights. Co-relate the plant response to the light number, for YOUR lights in YOUR tent. At least you have a meter, cause without it I have no idea what the plants are getting.

You missed this chart. You bought a ebay 500 (black line):



I am using this right now, and am about to get another.

https://growgeneration.com/photobio-advanced-quantum-par-meter.html

I kind of was scratching my head over this and I went back to look. Especially since this was an upgrade for an older version for me.

I compared the 500 to your supposed better 520. Dude they use the exact same sensor and the specs are the same. The 500 IS a full spectrum. The only diff is one is plugged in via USB to a laptop or desktop and the 500 is self contained. The difference is a correction factor for using UNDER WATER I dont know about you but I dont grow plants underwater.






From the Apogee website.



Apogee quantum sensor are calibrated to make absolute PPFD measurements in air. The waterproof sensors can be used to make absolute PPFD measurements underwater by applying an immersion effect correction factor, the SQ-420, SQ-520, MQ-210, and MQ-510 already apply the correction factor. For details on making underwater measurements, please refer to Underwater PAR Measurements.
Kind of puts a dent any any words from you. Sorry.

 

[flylowgethigh]

I kind of was scratching my head over this and I went back to look. Especially since this was an upgrade for an older version for me. snip...

Kind of puts a dent any any words from you. Sorry.

Really? I care not what your opinion of what I post up is. I am new at this felonious bidness of growing dope, and posting ideas as I find them. Hint, in a past life I made my living being technically competent. I am approaching growing like any other technical problem.