Optimal PPFD and distance for Max Flower Bloom/Bud Production - got some great tips to try and implement

It is relative to a few other factors -- so there is no "1" answer to this. One of the biggest factors is atmospheric CO2. this will be the bottleneck wihtout controlling it yourself. Hours of use is obviously important too... then you need to know how many umol/s your light produces... 1) what is your umol/s produced by the equipment, in total if more than one. 2) what is the area of coverage? convert to meters-squared. Looks like a 4x4 or 3x3 so 16/10.762 = about 1.5 m^2 or 9/10.762= .84 m^2 3) how many hours of use? 18 hours in diary We must convert your umol/s to PPFD in order to properly use the DLI chart. I'm not familiar with these samsun 2835 diodes. based on specs on amazon listing it is the LM281b+ pro... if not this is all wrong.. but that's the only one that makes sense given the 2.7umol/J efficacy. Good news is they don't seem to be over-driven. 300w / 1100some diodes is around .25watts per diode, so should be near samsung spec sheet values. However, the fact they are running at .25w/diode doesn't make sense... these very well may be the shittier LM281A+ which would drop your efficacy to 1.9umol/J and a drastically different umol/s output. 2.7 * 300 = 810 umol/s 1.9 * 300 = 570 umol/s Based on price of unit and brand, i'm very skeptical it's a true 2.7umol/J light... email manufacturer and the should tell you the exact diode it is... lm/w will be proportional... 213lm/w is roughly the 2.7umol/J.... the "1.9" i used is proportional to that using the LM281A+ diodes that are supposed to run at 0.25w/diode, as your light does. This inconsistency is a red flag that they have lied on their spec sheet (not samsung... their spec sheet is "god") I'm going to do best-case scenario and you can repeat same math with any other case. 1) 810 umol/s produced by the light 2) 1.5 m^2 garden 3) 18 hours of use. 810 / 1.5 = 540 PPFD (if 3x3, it is 810 / .84= 964 PPFD) --- Distance from canopy should be dictated by most even coverage and a little common sense... With a QB, 18-22" is probably a good range to stick to... can use a cheap lux meter to see how even the coverage is -- lux is proportional... 50% less lux under same light is 50% less umol/s. (lus can only be used per exact same light.. same CCT, same ratios of different diodes same everything proportionally speaking) Referencing DLI chart -- It says we want 600 ppfd over 18 hour to reach 38.9 DLI. So, you are up near the ceiling for atmospheric co2 in a 4x4 and WAY over it in a 3x3 (roughly 60 DLI would eventually kill most plants, lol). IMHO, in your context i'd use hous of light to further dial in.. if you want to give ore don't move light closer... keep it at optimal distance from canopy for best coverage of enterity of garden. Instead, simply add an hour or take away an hour based on plant's behaviour. try adding 1 hour. This brings DLI to 41. This needs time to show the full effect... so within 5-7 days you can make a determination if it is a positive or negative effect. light burns, excessive wilting at end of day, stunting of growth, bleaching of buds.... these are all symptoms of TOO MUCH LIGHT!! LOL They don't necessarily happen overnight.. the plant may not show how tired it is until a few days or more of 19/5. So, use dimming knob and hours of use to affect DLI. DLI is a more apples to apples undertanding of what is going on... regardless of size of garden or hours of light. For any small adjustment, i'd prefer to use hours of use or small adjustment of distance to canopy of light than a dimming knob -- more umol/s bouncing off walls hitting lower areas is good even if slightly wasteful with watts.. negligible difference in most contexts. So, again these are ballpark values... Temperature and RH will have an impact.. actual atmospheric CO2 may vary in a house... not so much outside. In the end you hve to observe plant and make sure it is happy. it's behaviour will dictate any fine tuning. Obviously, if the diodes are not the b+ pro version, the numbers turn out differently. Looking at 380 PPFD in a 4x4 and 680PPFD in a 3x3. This is great for a 3x3, but a bit underpowerd for a 4x4. TBH, this last bit is way more likely given price-point of the equipment. a sub 2.5-ish umol/J is virtually guaranteed... i highly suspect the listed 2.7umol/J is total bullshit, but "1.9" is too low for this price-point, too... so there is a lot of info given that doesn't make sense in their spec sheet. Big red flags... you'll need to email them for specific info and extrapolate from the samsung spec sheets with correct info for a more accurate guesstimate of umol/s of photons produced) Now, no worries... efficacy doesn't change quality of output (a lower dli but still greater than "21" will produce a bit less yield yet still of similar quality if you gave more light)... you simply pay a bit more in watts to achieve same DLI with a lower efficacy. If you are in a 4x4, i'd use more than 1 BP3000. in a 3x3, it's probably fine (if truly 800umol/s produced)... how the plant reacts will quickly tell you which umol/s estimate is correct. if in a 3x3 they'd probably be showing some light damage symptos by now. in a 4x4, they'd probably just be a bit light on yield compared to what you "could" do with more light. if on low end an in a 4x4, use the other lights to boost DLI. "380umol/s over 18 hours" is down near minimum you need to properly grow a plant. you will definitely see a boost to yield with more light, ceteris paribus. You can probably give a tad under 2x more light in this worst-case scenario.