Light burn does not coincide with too much heat in general, it coincides with low temps and low trranspiration. Infact HIR: high irradience response will generally be better with more heat.
1,020 watts boys of quantum board hlg goodness. Even have their hlg 30 uva and rapidled flower initiator pucks.
Let me rephrase that. When it gets hot my lights fuck my shit up. I don't get beleaching though, unless I raise par too quick. this sativa i'm growing hates anything over 80f, unless i turn down my lights. i estimate 800par average but i really need a light meter. and probably some automated shit.
I have no idea man. been winging it, but now I'm going off other peoples measurements I found. I did bleach a plant on my last grow with it though
Your lux is too high light intensity. Dim your lights down just a tad without a meter and you'll notice a huge difference.
You can download a free lux app on your smartphone for a general idea. Although not as accurate as a high end meter, it gave me a general idea. Also newer phones are going to be more accurate because sensors and whatnot on the phone are more up to date. But I was able to see at 16" my girls at 3 weeks of flower weren't getting enough lux. Roughly 35k. Moved them to 12" and it bumped it up to 55k.
So much of this is over my head. I don't even know. Perhaps its not a conversation for me to even jump in on anymore but I just ordered two 100w LED and two 125w CFL bulbs (for veg, clones,seeds and maybe a supplement?). I also have an LED that someone gave me for real cheap, it says 300w on it but I am thinking that means 300w equivalent cuz it is real small and I just don't think it pulls 300w. My space had to slim down a bit and is now a 2.5x4. I'm hoping between all of this I should be able to swing a decent crop. Or should I drop the $150 and get another 100w LED?
thumbs up. i did a cfl led light buld grow and the litle cheap dual head "grow light" frosted up the buds in its area the best. !
I have a 8 x 4 area with a fixture over each 4 x 4 section. Both use 8 hlg qb132 boards. The one on the left runs 640w @ 3000k. The one on the right runs 480w @ 4000k. During the winter I run autos and veg under the 480 then move to flower under the 640. This is my first run with photo plants and both lights, but given the wattage used I am quite pleased. If you can afford to go with higher wattage and dim down to allow for future needs.
Exactly. I'm just going off of what I am learning here and appreciate the conversation. Not sure if you are saying "yes, get another 150w LED" or that the LEDs I bought, that were mentioned earlier in this thread, are cheap in the first place." That being said. All the information here is great going into my first grow but I have to bookmark it so I don't get overwhelmed setting up.
Thats rather unusual. Generally speaking heat should be your friend especially under 80F but it could be your strain. Generally sativas would be less susceptible too heat. Maybe youre running to low RH pushing your plant into closing stomata due to too hot and dry? Anyways, grow the plant you got, in the end its abouut reading your plant.
Beautiful. I got HLG V2 3000k. So you're basically running 30w/sq on one side and 40w/sq on the other. Seems like I should up the ante a little bit but can possibly wait until flower to add another 100w LED. Thanks!
maybe its the 65-67f it gets at night? I grew an indica and it did the same. but yeah i am trying to learn my plant.
Photobleaching is from too much light. Because heat increases with light intensity, it would not be uncommon to notice Photobleaching when your environment is hot due to extreme light intensities. It also seems that at higher temps photobleaching is actually more prevalent. 3 things can happen when light is absorbed by a leaf. It can re-emit as heat (IR). It can re-emit as visible light through fluorescence. Or it can be used for photosynthesis. When Chlorophylls or other fluorophores become too chemically excited, they bond with molecules they were unintended to bond with and their shape changes permanently in such a way that they aren't able to fluoresce again. This is what photobleaching is. Photosynthesis: The plant leaf takes CO2 from the air, along with H2O and nutes being sucked up from the roots in the soil, and when the leaf is subjected to light, the CO2 and other molecules react to produce glucose & O2 gas. Glucose stays in the plant while O2 gas is given off to the surrounding environment as a byproduct to the reaction. Glucose is easily broken down (and used to produce ATP) and consumed during the night time or whenever needed. You can measure the change in CO2 concentrations, and/or O2 concentrations in a sealed room over a period of time to calculate the rate of CO2 assimiliation compared to various test conditions. Here they measured the rate of CO2 fixation vs temperature (Cannabis). The amount of CO2 being consumed by the plant reaches a maximal point and then drops off as the temp continues to increase. This shows the optimal temperature range for this MJ strain to be 27°C - 29°C (80.6°F - 84.2°F). In general, the amount of fluorescence you observe depends on the light intensity and the photosynthetic efficiency of the plant. If the plant can make glucose quickly, then it can handle more light to drive that process, but if the plant can't make glucose quickly, then it can't handle as much light. This is why certain plants like lots of light, and/or why certain plants like low levels of light. If a plant (PS reaction center) is currently busy with a process, then light that hits it is in excess to what's needed (the pigments already absorbed the necessary amount of light to energize a reaction center, and the reaction center won't be ready for more light until it's finished its processes), and if this excess light is absorbed, the plant will re-emit it as IR (heat), or visible fluorescence. When plants are fluorescing they are absorbing more than they can handle. When the light intensity becomes too great, the Chlorophylls become too excited and bond with other molecules which means they become entirely new substances or molecules. Upon this result, they are no longer able to fluoresce. They have been "photo-oxidized." Photoinhibition is the decrease in photosynthetic efficiency due to light intensity. We see that as light intensity increases, the efficiency of photosynthesis drops. Here it looks like above 800PPFD significant photoinhibition begins. Only about 6% of visible light energy is utilized for photosythesis, the rest is fluoresced as visible, or re-emitted back as IR (the lionshare). MIT School of Engineering | » Can we calculate the efficiency of a natural photosynthesis process? If your plant is reducing its photosynthetic efficiency, or if PS2 is damaged or stalled from too much light or heat, then you're leaving more energy for the NPQ processes (non-photochemical quenching; energy absorbed that goes into other things aside from photosynthesis, ie fluorescence and IR re-emission) to deal with given a constant PPFD. This means that if light intensity were kept constant, you'd see a little more fluorescence at cooler temps, and then as temps gradually increased to optimal you'd see less and less fluorescence, and then if temps continued to increase past optimal, your fluorescence will again begin to increase (hypothetically). Photobleaching is like fluorescence that went too far, so in reality, heat might impact photobleaching, but only to a small degree (only ~6% of the visible energy absorbed is used to create glucose, the rest is re-emitted as IR or visible light fluorescence), and not in a consistently linear fashion, ie not a "more heat = less photobleaching" way. I've not found much literature documenting ambient temp to photobleaching, though the one paper I did find seemed to imply that increased heat added to greater photobleaching (attached). Here's some links that I looked at that might be useful to others... Chlorophyll fluorescence—a practical guide How Does Chloroplast Protect Chlorophyll Against Excessive Light? | IntechOpen BleachingEffects | Scientific Volume Imaging Fluorophore Photobleaching Literature References