VPD Chart for CO2

After co2, oxygen to rootzones is next limiting factor of growth. Hope it helps 🌙 🐈. Goodluck.

Photosynthesis by day, Cellular respiration by night. Co2 is not needed at night so turn it off. Nights should be focused on respiration and dealing with excess moisture spat into the air all night long, keeping ambient canopy rh 40-45%. This keeps a constant negative pressure over night. Oxygen is what a plant needs at night, only oxygen diffuses into the leaves and only carbon dioxide diffuses out. Vpd is just a measure of temp and humidity. The drier the air the more space it has to spit more moisture out. All the energy the plant collects during the day must be processed throughout the night. Even getting your rh to 60% or there abouts causes everything to slow. If the plant only uses up 60 percent of all the energy it gathered the day before and doesn't process it all the same night the plant keeps a surplus which will detract from the next day's DLI At night you focus on 40-45% lights off , lights off deals with temps If you stick to 40-45 should keep you that turgor pressure optimal, negative pressure optimal, humidity optimal for quick removal of water vapor under stomata. Keeping 40-45 % should mean keeping temps around 73-83 should keep you in the "green" for most of flower with relation to vpd. You can't keep it perfect 100%, all the time. You will also be stunned at how much more water she needs to maintain the turbocharge cooling. Daytime priority is keeping temps under 86 and hitting a DLI of 40-60moles. Nighttime is maxxxxxxing out rate of respiration and getting rid of water ASAP. In order to make use of all the energy stored in the stems the plant needs to convert alot of the stored energy to sugars/proteins and then mix them with nutrients that water shoots up the rootzones, more nutrients,more nutrients until there is no energy stored in those stem. If we fail to optimize nights, like everything else with cannabis plants, the entire production of the plant as a whole will bottleneck at the place in the production line that is least efficient. If your plant is only dealing with 40% of energy it stores from the dalight hours then you are running at 40% of total capacity for everything no matter what you do or how you feed or anything. 9 cardinal rules of growth all must run in unison, any 1 runs at 10% efficiency then everything else will bottleneck to that 10%. That's not even taking into consideration the feeding plan....if your feeding concentrate you need to calculate for that. I myself took the path of packing everything the plant will ever need and then some into the soil, therefore letting the plant dictate its own feeding schedule based on the demand the environment places on it. This is a key factor affecting photosynthesis. Low CO2 affects the Calvin Cycle. If CO2 levels are low, rubisco cannot convert RuBP to GP in step one of the Calvin Cycle. This leads to accumulation of RuBP and an overall slowing of the Calvin Cycle, which results in a fall in the production of TP/GALP. Co2 increases the rate at which plant can convert energy it collects to carbohydrates. 40 moles per day at 400ppm. 60 moles per day at 12-1500ppm. We learned that light intensity, carbon dioxide concentration, and temperature are the three main factors that impact photosynthesis. Greater light intensity leads to higher photosynthesis rates, as does increased carbon dioxide concentration.

I'd adjust fertilizer formula before major tweaks to VPD. I believe vpd suggestions impact a wider variety of biological processes than just photosynthesis concerns and probably best to stick with general suggestions per stage of life for that reason. VPD impacts rate of transpiration, which directly impacts rate of drinking. You can either supply greater mass of nutes per day to support increased growth rate by increasing VPD or feeding at a higher concentration. I think moving 1 lever is more likely to be a better option than a lever that impacts 'other' stuff, for lack of enough biology education to give specifics. May not need to adjust P or K as much as others (rely in greater proportions on "active transport" to enter plant) Required increase in fertilizer concentration won't necessarily be a proportional match to increase in rate of growth. e.g. supposedly you can get 25-33% greater yield, which for simplicity sake of this point assume growth rate is also 33% increased, but it'll probably be less than a 133% increase to concentration to maintain good growth -- has to do with some nutes being taken in through active transport more so than basic diffusion of water (mass flow). The critical levels of these nutes around roots for best uptake without impeding other things won't change. Trial and error... because a simple +20% across the board may not account for everything in the proper proportion. N is mostly taken in through mass flow, so that would need a larger increase than p or k, i would wager. Active transports happens on demand (some sort of feedback loop). I have not learned anything specific to this species, but how nutes enter plants are going to be similar to others, even if not a gaurantee. Chemistry of it is the limitation on potential variety. the carrier molecules will be similar if not the same, because it's like a lock and key fitting together - exactly how it can selectively grab (bond with) a specific type of molecule and not any random thing floating by. the excerpt seems to hint at 'lower' vpd being beneficial eh? Feeling good about my half-educated guesstimate, lol. Raise the nute conceentration, not the VPD is my best guess. Take notes and err on low side till you get it fine-tuned. Little sacrifice this grow to have greater confidence in the next and a shorter learning curve.