What is happening??

The image appears to show a close-up of a cannabis plant's leaves. Some of the upper leaves exhibit a yellowing or discoloration, suggesting potential nutrient deficiencies or environmental stress. Based on the visual evidence, it is likely that the cannabis plant is experiencing nutrient deficiencies or environmental stress. The yellowing of the leaves is a common symptom of these issues. To provide a more accurate diagnosis, it would be beneficial to have additional information: Growth Stage: Knowing the current stage of the plant's growth cycle (seedling, vegetative, flowering) can help narrow down potential causes. Nutrient Regime: Understanding the type and amount of nutrients being provided to the plant is crucial. Environmental Conditions: Information about the plant's environment, such as light intensity, temperature, humidity, and watering frequency, can also be helpful. General Recommendations: While a definitive diagnosis requires more information, here are some general recommendations: Nutrient Check: Ensure the plant is receiving adequate amounts of essential nutrients, particularly nitrogen. Consider conducting a soil or nutrient solution test to determine specific deficiencies. Environmental Assessment: Review the plant's environment and make adjustments as needed. Ensure proper light intensity, temperature, humidity, and watering practices. pH Levels: Check the pH of the soil or nutrient solution, as incorrect pH can hinder nutrient uptake. Pests and Diseases: Inspect the plant for any signs of pests or diseases that could be contributing to the leaf discoloration. Additional Information: If you can provide more details about the plant's growth stage, nutrient regime, and environmental conditions, I can offer more specific guidance. Additionally, if you have any other images or symptoms, please share them for further analysis. I hope this initial assessment is helpful. Please feel free to provide additional information for a more precise diagnosis and tailored recommendations.

Excess light need to reduce the amount of light.

You're gonna find a boatload of people on here who can recite the "perfect conditions" a plant can be grown in and their only "cure" is to recreate their perfect conditions. That doesn't always make supporting and sustaining these conditions practical though lol. Ask these same guys how to grow outside of these perfect variables and it quickly becomes s#!t show. 32C isn't all that hot and I've NEVER grown a plant at optimal VPD, 50% is no biggie. How on earth would ANY plant survive in a large scale greenhouse if that was the case? In the summer the sunny side of our hoop houses at work can climb to like 50C. I wonder if all these values even apply to THIS grow considering they're being pulled from a diary you planned to chop 4 months ago... so more info is probably required. I suspect it's nothing more serious than a pH fluctuation. It could be light burn from condensation on the leaves, more airflow would help there.

Your vpd is sky-high. it's a bit too warm, like others said. If you can cool it a few degrees and get your atmospheric vpd closer to 1.2-1.3 (it's lower at leaf due to cooler temps around leaf, -4-5F offset, reference VPD chart) You may not have to adjust anything else. A little high RH will mitigate at least some portion of what is causing this, all other things remaining the same. Even so, i'd still reduce temp a few degrees if you can. 83F would be better. More efficient lights would reduce heat while maintaining same DLI, but that's a thought for the future. Probably cut 5-7F off with 2.8umol/J efficacy lights. The other danger of high temperature is the high absolute humidity. As temps drop, RH% has the potential to skyrocket and hit dewpoint at fairly high temps, like 70-72F. When this happens it's a very very high risk of WPM getting a foothold with consistent condensation potentially occuring after lights go out every day. Can't easily find good info on the cr600 light. if it's 588 lm301 diodes, it's overkill, lol, but that's a good thing if so, but not likely the case because it is overkill and would impact profit margin. So, assuming it's a lower efficiency light. figure 2 sq ft under 1 of those lights (possibly slighty smaller, but matter of and inch on LxW at most) and slightly rectangular footprint proportional to diode layout. 18-20" should be fine for this light. "Sanan" LED .. might be a licensed knockoff of a sammy or osram chip? more likely the heat than the light. Those numbers and footprint above are for 12/12 light cyce, so in vege operating 18hours a day you'd want about 65-70% power, all other factors the same. when you go to flower, then you want 100% power. It is inversely proportional to hours of operation 18h - 12 requires 150% to maintain same DLI as before. 1.5 * 66.67 = 100%. different operating hours would need different math. Also, the DLI target is 35-40 with ambient co2 and some local tweaking necessary to dial it in for your local variables. your "max dli" will be different than someone else's due to different local variables, but it's a good ballpark to start.

Can you move the light higher over the plant? I like to be at 24" during flower. You can also turn down light intensity. Both should result in lower temps for your plant.

Put a fan or multiple on your canopy too cool down the heat from the lamp itself and light.

Looking at your diary, it says you have 32°C? That’s too hot. You should aim for a maximum of 26°C to 28°C. I assume your plant is getting too dry as well. They consume a lot of water at these temperatures.

Too much light change light mode on 50-65% from maximum.it should be switched to maximum at the final stage of flowering