PPFD ???

Sorry, as I was digging studies about camera and quantum sensors, I found something very interesting everyone should be aware of, so I debunked Polyphemus bullshit anyway. :3 growdiaries.com/grow-questions/63890-puis-je-faire-confiance-en-mon-smartphone-pour-mesurer-de-ppfd-

Just act nice to eachother people! Agree to disagree and move on. The best answer so far is from Heavy Hittah I would take his advice. Now smoke a spliff and relax! 💚

@Scrubbyjimbob well… Polyphemus is the only one getting angry here. I think some of his arguments are debatable. But given that he is not very open to debate and that, on the contrary, he tends to invent things to discredit his opponents, I prefer to be sure that he is prepared to hear what I have to say before spending my time writing and documenting my argument in a language that is not my own. In fact, apart from trying to make him understand that he should synthesise his words a bit more to remain accessible, he never really allowed me to present any of my arguments. > Smoke more weed ya'll..... Fuck combustion. :3

This is what happens when you get too sciencey....nerds get angry and assign you calculus homework. Unless you're working with custom lighting or multiple lights, you're worrying waaaaay to much about this. Use the manufacturer recommendations as a starting point and dial it in based off how the plants respond. Are their calculations perfect? No of course not, but they're ballpark enough to get you in the right neighborhood. Different plants will vary slightly in what they like anyway....which is why DLI is offered in a range to begin with instead of an exact figure. Smoke more weed ya'll.....

> What is it your trying figure out @BRANDFROMTHE6 is trying to figure if his plant receive enough light. (sorry for the mess)

What is it your trying figure out

The question I'm really asking you here is are you willing to accept the possibility that someone has good reason to consider that you've made mistakes in your reasoning?

Do you want me to debunk you? Yes or no?

Someone needs an algebra lesson? umol/m^2*s^-1 - fancy way of writing umol / m^2 / s -- operational order requires no more symbols (PEMDAS). This is the equation for PPFD written 2 different ways that mean the exact same thing. it should be easy to see how i used this exact equation to do all the math below. You can verify this at any number of websites. A DLI table for easy reference helps too. This isn't hard to understand and it works very well. I've used this method with several lights and it should be within 5-10% of what anyone needs regardless of area of coverage or hours of operation. photoperiods or autoflowers.. just takes a little math deductive reasoning. You keep "calling me out" and being really loud about something you clearly don't understand. It's getting comical at this point. Read the wiki on DLI. Read the wiki on avagadro's number (a "mole"). Do you know what "^-1" means? There's gotta be something simple here that's tripping you up. Basic algebra is all you need to see this in the equation. it's as simple as solving for the unknown. 35-40 DLI produced by lgiht relative to space illuminated and basic common sense applied, is a good target. Then through observation of growth you can easily fine-tune it further, but you'll start in a spot that is very near to optimal. Every environment differs, too. Environmental variables cause variance in "optimal" levels too. There's no 1 answer. it's just a good starting point. If buying a light for an existing space or all together, this sort of planning will avoid wasted watts or undersized lights in a very reliable way.. in fact i'd say it's impossible to buy the wrong light using these methods. you'd have to use bad information for it to not work.

Fems Seedlings 250 Veg 350 to 500 Flower 550 to 900 Autos Seedlings 250 Veg 350 to 450 Flower 450 to 650 Autos require less intensity as there lights are on for longer in the day which increases your DLI . Don't go over 40 DLI for autos. It is also important to keep your VPD in range if your maxing out your plants. If environment is not on point then don't max out the plants it will stress them. Environment is just as crucial as lighting. What ppfd meter do you have ?

This is a hot topic and I agree with Some of the points below. Referencing a DLI chart is a much better option to find the sweet spot. Cannabis can take uptp 35-40 DLI, If DLI is new or confusing to you, look it up with introduction videos by Dr.Bruce Bugbee, hes a professor who studies Cannabis and Light, he aslo has some fancy tools made by his company to measure this stuff. but they are not cheep. You can do a ruff estimate of your DLI by using the PPFD maps that light manufacturers provide. its not perfect but its better then just guessing. I realized I was blasting my plants with close to 55-60 DLI before so I changed it to prevent light stress and bleaching. Some clips helping to understand DLI from professionals. www.youtube.com/watch www.youtube.com/watch Good Luck!

Polyphemus, the first time I caught you talking shit, you refused to accept you could be wrong. The second time, I said nothing and make a meme with your nonsens. So today, I'm asking you a question: do you want me to properly debunk you?

Stop your bullshit Polyphemus.

oh your diary said 400w custom.. here it says 300w mars. if it is a mars they have accurate spec sheets for the last 2-3 years, so you can use that data reliably. follow steps below armed with your umol/s produced from light.

can even se it in other answers.. confusion of ppfd vs umol/s. PPFD is light per second per area it is focused on. thse are measured as umol/s of photons and m^2 for area. It is not a single point measurement. That is umol/s, not ppfd. reference a dLI table with hours of operation and PPFD to find DLI. 35-40 DLI is about as high as you should try to go with ambient co2. Trial and error / observing the plant is always required to find "your" max DLI. like i said below, many factors impact what the max DLI is for your garden compared to another's. 35-40 DLI is a ballpark idea that requiers you to observe and react to fine-tune it. 400watts custom mlight..no idea of efficay, but calculating what you can provide can help start in a better ballpark. watts x efficacy = umol/s produced umol/s divided by area of coverage in m^2 = PPFD now reference a dli table. if it's drastically different than 35-40 DLI you know the direction you must adjust. This assumes you hang the light in a way that most effectively covers your garden. this is where proportional intensity from your app readings can help. Don't sacrifice too much in stronger areas for edges and corners, but some sacrifice can result in a higher average DLI across the canopy. the app readings won't help much until after you find the best amount of light to give, which takes observation + trial/error on your part.

i think this is a confusion of vocabulary or using a phone app that has its head up its own ass. what you have is an app that mesures lumens then converts it to umol/s... but due to varying characteristics of light produced by 1 model vs the next, this conversion factor is not a one-sized-fits-all context. there can be significant error caused by the conversion without tailoring it to spectral flux density of the light in question. As far as a know a camera lense on a phone is not capable of such things. You'd need a bluetooth probe that could do it... or just buy a quantum meter for 400-500USD, lol. it's still useful info once you have things mapped out. Proportional intensity is consistent. If it is 50% at edge compared to the reading directly under center of light, you nkow the umol/s is also 50% of center... you may not know what that center value is, but you know the edges are 50% of it. common sense and some trial and error based on observing theplant will fine tune hanging distance, power etc. At that point, this information can be very helpful in optimizing light across a canopy without a need for an expensive quantum meter. So, Observe the plant. Are the internodes too long or too short? Are they a healthy length? Do you ahve any light damage? these are things you watch for and react to in order to adjust your light. there will not be a specific PPFD you can follow in an exact way. Too many variables impact how much light a plant can receive per day. Ambient co2 levels vary. temps vary. RH% varies from garden to garden. You will always need to engage in some trial and error to learn the best way to use your light. Do take some notes for each use -- vege vs bloom ... seedligns, clones, mature plant etc... Don't worry so much abvout what the reading says.. it's more about how the plant reacts and the readings help interpret. I think what you are measuring is umol/s despite whatever the app is calling it. 150umol/s over a small area can result in very high PPFD. It depends on teh geometry of the coverage of light. if 150umol/s is focused on 2sq ft, for example, this is 75umol/s per sqft x 10.76 sqft/m^2 = 807 PPFD in that 2 ft^2 area -- assume it is focused properly and refelctive walls etc etc.. keeping it simple and totally normal context in all other ways. 807 is enouigh power for a 12/12 cycle and too much for a 18/6 cycle. this would damage plants on an 18/6 cycle in a 2ft^2 garden with 150umol/s of light properly focused on it. Now, your plant looks okay, from what i can atell.. Not too short, not too lanky, but due to the angle of the photo, can't be 100% certain. if the new growth doesn't have a proper internode length adjust your light -- power, distance, hours of operation are all tools. Hours operation do need to adhere to biological parameters of the plant if it is a photoperiod. i.e. if you give 10+ hours of uninterrupted darkness, it'll go into flower phase. i would hang light at a distance that gives you the most even (umol/s readings in specific locations) and strongest overall coverage (average umol/s across canopy). This is about basic application of gemoetry and beam angles. Once that is consitent, then work on trial and error finding the most light you can give per day given your local variables. The internod length is your guide. this is the stem that results between two growth nodes. New growth will be sensitive to light. It will quickly tell you if the light is too intense or too weak. Adjust based on what you see.. give it time to show the new effects and repeat this process until the plant's growth pattern is healthy and vigorous. no stunting.. no stretching... Now, once you have that figured out for your vege phase, it'll be easy to translate it to bloom phase. If using 18/6, you'll need 150% more power over 12 hours. You can see this is 1:1 inversely proportional to hours of operation. 2/3rds of housr (12/18) requires 150% power (18/12) to achieve same DLI as ayou gave before. the max DLI a plant can take per day is not affected by vege or bloom phase. it will still be 35-40 DLI max --- not what phone app says but REAL DLI, lol. whatever the phone app reads after the above trial and error is complete, that's your "max DLI" even if the value is wrong, it will be calculated consistently by your phone for that 1 specific light... any different light will potentially be erroneous in a different scale unless the light has teh exact same characteristics (SFD, CCT, etc). Trial and error... all you got. Take notes. Refine it for each special need - seedling, mature plant, clones... vege vs bloom. If possible, keep same optimized hanging distance, but may need a closer hanging distnace from 12/12 cycle if the light is a bit underpowered. the edges and corners will suffer a bit, if so. always size a light working backward from greatest need.. for marijuana that'll be a 12 hour light cycle if you grow photoperiods or want to grow photoperiods. this way your light wil be able to hange at same distance, have same coverage and penetration but only have to adjust power.

Overal op het kweekoppervlak zou je een PPFD waarde tussen de 600 en 900 µmol/m2/s moeten hebben. Waardes onder de 200 µmol/m2/s is eigenlijk te weinig voor wietplanten.

i also think 150 is too low for this stage, its not a seedling anymore. check your LED manual, what does it say which hanging height and how much % do you need for veg?

150μmol/m².s is very low to me. You can start increasing gradually to reach 400μmol/m².s and more.