Understanding PAR PPFD and PFD To Maximize Cannabis Yield

Understanding PAR, PPFD and PFD To Maximize Cannabis Yield
Professor DeBacco
Light Intensities Importance
Light intensity levels can have a significant effect on photosynthesis rates, which are directly related to a plant’s ability to grow.
Measuring the light intensity involves a few different options so it is important to know the background of each.
Lumens are for Humans
The lumen is the SI derived unit of luminous flux which is weighted according to a model of the human eye's sensitivity to various wavelengths.
Essentially it contains the wavelengths humans can easily see.
No connection to photosynthesis of plants (unlike PAR).
PAR (Photosynthetically Active Radiation)
PAR light is the wavelengths of light within the visible range of 400 to 700 nanometers (nm) which drive photosynthesis
Measured as Watts/m2
Note: Chlorophyll absorption is higher in the blue and red portions of the light spectrum, so two light sources can have the same PAR output but depending on the wavelengths produced can have different plant performances.
PPF (Photosynthetic Photon Flux)
PPF provides the number of photons in the 400-700nm wavelength range that drive photosynthesis, which are emitted by a light source, same range as PAR.
The unit of the PPF value is µmol/sec
This is the quantity of light particles emitted per second
Simply PPF = Amount per Time.
However, PPF does not consider the direction in which the light is emitted which means it does not indicate the light that actually reaches the leaves.
PPFD (Photosynthetic Photon Flux Density)
PPFD provides the number of photons in the 400-700nm wavelength range that drive photosynthesis, which are emitted by a light source, same range as PAR and PPF
The unit for PPFD is µmol/(m2s)
PPFD tells you how many photons which drive photosynthesis impact an area per second.
Simply PPFD = Amount per Area per Time
Comparing PAR vs PPF vs PPFD
PAR is a generic term still used in common speech to refer to energy flux or photon flux.
Unit: Watts/m2
PPF is used for the amount per time.
Unit: umol/sec.
PPFD is used for an amount per area per time.
Unit: umol./(m2*sec)
PPFD helps define the intensity of the light over a given area.
Limitations of PAR and PPF and PPFD
All of these are bound by the 400-700nm wavelengths of light.
However, in particular with cannabis research where the UV and Far red wavelengths are of interest these above terms do not take into account these wavelengths since they are outside of the 400-700nm range.
So to take into account greater wavelengths there is PFD
PFD (Photo Flux Density)
PFD is a measurement of the number of photons in the 300-800nm wavelength range passing through a particular area per second.
The unit is μmol/m2/sec
Simply PFD = Amount per Area per Time
Measures 300-800nm
Not limited to the 400-700nm “photosynthetic” wavelengths
Take into account the far-red and ultraviolet radiation
Units Are Important!
Always check the units used in any work you are reading!
micromoles per meter squared per second (µmol/(m2s) is key and is what PPFD is measured in.
Light Sensors
Light sensors are the primary instrument used to quantify the light intensity of horticulture lighting systems.
These sensors work by using an optical filter to create a uniform sensitivity to PAR light
Growers will use this style for a point in time measurement but some options to connect these to a data logger can allow for an accumulation of readings for different day to day comparisons.
Measuring PFD (340-1040nm)
Apogee MQ-620 Extended Range PFD Sensor allows for UV and Far-red photons to be measured.
Research has shown value of adding UV and far-red.
The 1040nm top cutoff also means the sensor will measure the thermal output of HPS fixtures and other broad-spectrum lights so, the sensor is intended only for use in LED environments.
How Can This Help To Maximize Cannabis Yield?
Since cannabis is a high light tolerant plant there are more potential options when it comes to lighting.
With the ever changing artificial lighting market, understanding these terms can help growers make informed decisions.
Also, with cannabis the secondary compounds are also of importance so providing plants with wavelengths outside of the PAR/PPFD spectrum may be advantageous when it comes to maximizing yield.
Special Thanks To…
Combination of research data from…
Dr. Bruce Bugbee of Utah State University and Founder of Apogee Instruments Inc.
Shane Torpey MICRO founder
Professor Erik Runkle of Michigan State University
Link to Lecture Slides: drive.google.com/file/d/1dDrZ...
*Due to the description character limit the full work cited for "Understanding PAR PPFD and PFD To Maximize Cannabis Yield" can be viewed at... drive.google.com/file/d/1XLdm...

[@stevehillbilly5797]

As always another great video. Bruce Bugbee is an amazing asset to the growing community as a whole. Agricultural and personal small scale. Take care stay safe and peace.

[@DeBaccoUniversity]

Thanks, the goal is to take some of the information already shared and summarize it and also apply it to actual growing situations to provide people with relevant and scientific based content.

[@muthrfuqrjonz3530]

Something that I certainly need to invest some time in learning. Thank you Professor.

[@DeBaccoUniversity]

You are welcome, you can also use this video as a reference/reminder as it has a lot of fundamentals covered.

[@stewiepid4385]

The wavelengths outside of the PAR/PPFD are achieved in my grow room by using 'Finishing Bulbs'. I use 2 types: 1. A high UV MH 1000W bulb, ( less than 400nm ) and barely any infra-red and yellow spectrums, ( 750nm - 550nm ) the last two weeks of vegetative growth. This improves flavors and aromas. 2. A high IR HPS bulb 1000W, ( greater than 750nm ) the last two weeks of flowering. This is in agreement with Dr. Debacco's data as this causes the calyxes' to swell 35% - 50% more than if just kept on a Full Nova spectrum HPS bulb, thus increasing yield gains per SOG/SCROG ratios.

[@DeBaccoUniversity]

Thanks for sharing your experience, there will be a video coming out soon comparing some of the options regarding CMH bulbs that will be similar to the concept you have shared here. Great to see contributions from people in the comments!

[@MrOrangeQueen]

Incredible channel! I was really angry that YT would not let me watch this because it is Cannabis-related (I am located in the EU). VPN + Script solved my problems fine. As you did with my lightning-questions! Thank you so much!

[@DeBaccoUniversity]

Glad you were able to find a way to make it work for you!

[@joeborovina4769]

Still a reference Professor ! thanks again

[@DeBaccoUniversity]

Glad to provide quality and time tested content!

[@howibleed8479]

Great video-im glad i found your stuff! keep up the great work!

[@DeBaccoUniversity]

DeBacco University is happy to be found by you, please help spread the word about the channel to others!

[@dr.trichome6419]

Love this research i used it when i was shopping for lights. Great video!! 🔬👨‍🔬🤙

[@DeBaccoUniversity]

Hope this helps you become an informed and educated consumer.

[@SouthAfricanCannabisExtraction]

Your content is really stellar, succinct and well researched. Thank you for the effort you put into this channel!

[@DeBaccoUniversity]

Your noticing this and commenting are truly appreciated! Be sure to share this channel with others!

[@SouthAfricanCannabisExtraction]

@@DeBaccoUniversity Definitely will, your channel is an amazing resource! Especially to remote locations like Africa, where we are split from the cannabis expertise in Canada and certain US states.

[@tiagobraga5206]

Thanks for the video!

[@DeBaccoUniversity]

Thanks for watching!

[@joeborovina4769]

Outstanding Professor ,thank you

[@DeBaccoUniversity]

You are welcome!

[@zachfinnie288]

I'm really loving ur videos keep em coming man 🙂✌

[@DeBaccoUniversity]

2x daily content can not last for ever, but enjoy it while it is here;-)

[@Brazilbroker1]

Excellent video, great job explaining a complex topic.

[@DeBaccoUniversity]

Glad you liked it, you have described the goal of this channel;-)

[@jacobcolunga2665]

Im going too have to watch this video again.😄

[@DeBaccoUniversity]

Pause, take notes and rewatch.... this additional time spent will be worth it;-)

[@Winnetoo85]

Danke!

[@DeBaccoUniversity]

Thanks!

[@andrewwhite1576]

The light intensity won’t decrease by 25% it would be 75% for a given area at twice the distance. You would be only receiving 25% for given area at twice the distance

[@DeBaccoUniversity]

"...when you double the distance the light intensity decreases to 25%"

[@Chessdot89]

Thanks 😊

[@DeBaccoUniversity]

Welcome 😊

[@christianbureau6732]

Thanks

[@DeBaccoUniversity]

You are welcome!

[@peter2945]

Did you talk anywhere about the idea values for the plant in question....that is what we were all hoping to learn.

[@DeBaccoUniversity]

This continuation video may help answer the question you asked... kzbin.info/www/bejne/q3K0kJuba8d4pbs

[@peter2945]

@@DeBaccoUniversity That link was very helpful and explanatory. Thank you very much sir! You are the man.

[@AdinPlays]

hey brother i have a question, i have 4 plants which are sitting at 300 ppfd and they arent stretching much and im about to flip them to flower, for the preflowerimg stage (first 3 weeks of flower) should i keep the ppfd low for them to stretch? or give them the ppfd needed? im scared that they wont stretch if i give them the ppfd needed right now

[@AdinPlays]

pleasse

[@DeBaccoUniversity]

In short... give them the needed ppfd.

[@c.j.mackay4032]

First I’d like to thank you for being so responsive this week with my comments, I have a quick question that I hope you can give me some insight on. As I sit here and do a bunch of math using PPFD maps and calculating the DLI I can potentially achieve with various power levels, distances, and light schedules, I had a question. If I assume that 12” provides 100% intensity, (as per manufacturers directions for LED light) and that double the distance, 24”, provides only 25% of that intensity, could I work this equation in reverse? For example would 6” then provide 400% of the light intensity? I know that is extreme lol but even if I could achieve 150% of my potential PPFD from my lights it would allow me to bring my photosynthesis up to an optimal level without purchasing any new equipment. Thanks so much for your informative video!

[@DeBaccoUniversity]

In theory your math and thought process are correct. However, what you are not taking into consideration is the light intensity and coverage area since when you are talking about plants this is also another important factor. Intensity over what coverage area based on the distance to the canopy needs to be factored in as well;-)

[@andrewwhite1576]

It’s all about DLI

[@DeBaccoUniversity]

Tune in tomorrow May 13th, 2021 @ 11:00am ET and there will be a video going into detail on this very topic;-)

[@brasco8721]

I just added a UV/IR light to my grow, the Mars Hydro UR45. It seems the UV is UVA. They are on independent on/off switches. I'm trying to figure out how often and when to use them during the grow. When would you recommend using the UV/IR during the grow? This will be for autoflowers. Thank you!

[@DeBaccoUniversity]

Step 1 would be to reach out to the manufacture to see if they can provide any recommendations. UV and IR are what outdoor plants naturally get so the plant can use these spectrums.

[@lp6132]

Ive got a lumatek zeus pro 600w led ( known as the photontek x 600w pro in the us and canada ) It gives out a PPF of 1620 µmol/s at full power. It comes with dimmable adapter and was wondering what sort of output i should be looking for at different stages of growth. I don’t see the point in amping up my electric bill by having the lights at full 600w power throughout seedling and veg stage if it doesn’t need it. What would you recommend through different stages of the grow. It has 25%, 50%, 75% and 100% adjustments. Any feedback would be much appreciated 👍🏼

[@DeBaccoUniversity]

The % do not mean much, you want to measure what your plants are getting in PAR at plant height. In short flower should have the highest PAR readings.

[@lp6132]

@@DeBaccoUniversity thank you for feedback, very much appreciated 👍🏼

[@chrisbethmann3955]

You are priceless

[@DeBaccoUniversity]

Thank you for this high praise!

[@popeyethepirate5473]

This is beyond me

[@DeBaccoUniversity]

The key is to keep on learning and if you revisit this video in the future it may prove to be helpful for you. Keep wanting to learn more and you will go far!

[@FXPips11]

@3:23 confirmation to why par meters are this industries biggest scam, its still light intensity at the end of the day, as it doesnt take into factor 400 < or

[@DeBaccoUniversity]

They are a tool to use, but growers need to understand the limitations of any instrument they are using.

[@FXPips11]

@@DeBaccoUniversity no doubt, just sayin, $155 cheap end, to give crunched numbers with fuzzy math,

[@dano9411]

Algorithm

[@DeBaccoUniversity]

Be sure to share the channel with others!