PPF, PPFD, YPF, DLI - A guide from Invisible Sun led

[TheCloudyChef]

PAR is a measurement of Photo-synthetically Active Radiation within the 400nm-700nm range, this is the range of light plants use to photosynthesize. Plants utilise this range of light, the light reacts with Chlorophyll a and b and converts light into energy to grow and thrive.

Photosynthetic Photon Flux Density is measured to determine the amount of micromoles per meter per second µmol/sm²

Using this figure and some further information we can determine information like par maps, umols/J and also DLI



PPF - (Photsynthetic photon flux) is the amount of light which is in the range of 400nm -700nm that is being produced by a lighting source per second. measured in the umol / second.



PPFD - (Photo synthetic photon flux density) PPFD is a measurement of how many photo synthetically active photons reach your canopy. PPFD is important to understand so that you are giving the right amount of light to your plants. It is measure in μmol/s.m². Between 700 - 900 μmol/s.m² is the ideal amount of light for crops which require high light intensity such as flowering crops.

YPF - (Yield Photon Flux) is measurement where photons are weighted in the 360nm-760nm range, it goes deeper than PAR by extrapolating the photons to the plant sensitivity curve per crop. If you have an exact spectrum produced by your grow light you can alter the umol / second values by adding additional colors such as 450nm, 660nm or even 730nm

DLI - (Daily Light Integral) This is the amount of light which a plant can receive and process in a day, it is a combined total of the the amount of photons (umol/s) which reach the plant in a day. The total number of umol is measured as a mole.( mol/d.m² )
Utilizing DLI can be beneficial in making sure your plants get the right amount of light each day, working out exactly what ppfd you need at canopy level will give you the information you need to determine what your daily DLI is.

Using the calculation

PPFD x Hours of light x 60 x 60 / 1000,000

For example for a DLI for light intense flowering crop you should be aiming for the region of a DLI of 40. Using the calculation above we can determine the DLI.

Lets say we have a ppfd measurement off 950 umol/s.m².,

950 x 12 hours x 60 minutes x 60 seconds / 1000,000 = DLI 41.04

So you can see by the calculation above that being in the area of 900-950 is going to be the perfect par for flowering crops.

Another example would be for vegetative growth stages, in this stage a lower DLI is required of around 15 -20 If we start with a PPFD of 400 umol/s.m².

400 x 16 hours x 60 minutes x 60 seconds / 1000,000 = DLI 23.04

By using DLI it give you an effective way to measure the exact amount of light your plants will receive daily.

As a guide, Flowering Crops require 20-40 mol/m²/d and vegetative stage required 15- 20 mol/m²/d

[IMO]

This is an amazing write up! Thank you for explaining it all! Some of us are led light illiterate this is super helpful

[Keeno]

Brilliant info @Invisible Sun. I'm sure it will help many.

[GMO]

great write up buddy.

YPF needs just a little more to it in regards to the photon weight and how plants can respond to monochromatic light in different spectrums due to the photon weight IE the amount of energy carried by blue is higher than red photons. but then doesnt account for the interdependence of colours on photosystems 1 and 2

[ncrypta.core]

Nice right up but cannabis dli can be up 60 or even more but c02 is needed . Heard 40 is ideal

but lets take portland for example


This is expample of ideal dli:

[2-Scoops]

You might as well be talking Chinese with all that tech talk, maybe I'm getting old and lazy, but i can`t get my head around any of that these days. Your lights are very bright though.

[IMO]

Nice right up but cannabis dli can be up 60 or even more but c02 is needed . Heard 40 is ideal

but lets take portland for example


This is expample of ideal dli:

DLI for indoor growing is different to out door growing, due to the fact outdoor can fluctuate over days , weeks and months. There is research looking at expanding DLI into a weekly intake and monthly intake of light.

Cannabis can certainly handle a higher DLI, out doors in such locations it clearly has too as we cant control the amount of sunlight outdoors, but the question is does it take in the extra light ? we could provide larger DLI levels but cause stress and stunted growth. A DLI of 40 is optimal for Canna varieties

[GMO]

Nice right up but cannabis dli can be up 60 or even more but c02 is needed . Heard 40 is ideal

but lets take portland for example


This is expample of ideal dli:

Ya need to look at the data sets missing from some of the graphs you share mate. they have just plotted something on a pretty image but there isnt really any information to gain besides "they said this" with these kinda info graphics. Temp, CO2, nutrient regime etc etc etc. just lots of holes where they are only selling one piece of information then they offer the same data in a different number format by stating the ppfd by weeks

CRAAP test - https://researchguides.ben.edu/source-evaluation

[GMO]

You might as well be talking Chinese with all that tech talk, maybe I'm getting old and lazy, but i can`t get my head around any of that these days. Your lights are very bright though.

This info allows you to compare lights far better than by eye is all mate

we are at the point that lights are like bottled nutrients ie you can by a brand you like and have been told works (at face value and review the results) or ya can compare the specific msds of each for compounds used and truely compare similar products

[ncrypta.core]

Ya need to look at the data sets missing from some of the graphs you share mate

lol what data is missing. Only shared an example of what the average dli of portland is not c02 or temp or anything. the dli from what I know is the light intensity. Lmao. a lot of people think the ideal dli is including jermay from build a soil is 40.

You need c02 once you go over 1000 ppfd. but don't remember every seeing you having to cal the c02

through It was

PPFD x (3600 x photoperiod) / 1,000,000 = DLI

Some of the many source I researched
https://gpnmag.com/article/what-to-know ... f%20growth.

https://mammothlighting.com/pages/photo ... s-sativa-l

Dr. Bruce Bugbee

https://www.lumigrow.com/learning-cente ... ing-guide/


could keep listing but why as all this is bullshit lmao?