Aqua Man
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that low rh? Every vpd chart i see says .8-1 for vpd and my leaf temps are 78* that puts me between 70-75% humidity for late veg growth on the chart I have. Im in nectar for the gods #4 soil. Thanks for the replysUnder LED when in doubt run 50-55% RH and 75-80F air temps.
What media are you in?
Hope you aren't watering soil like this.Interesting I was going off this chart pic for environments. Ill lower rh.
I dont know what calculations you are using but it most certainly does NOT put you at 0.8-1…. It puts you at 0.48 and thats NOT okMy rooms conditions are spot on with vpd, co2 and feeding regimen. Any time i try to get lights in the optimal ppfd range all my leaf tips turn over and turn yellow on all my new growth. My room is 82* 72%rh 1200 co2. Im growing in soil with nectar for the gods. My soil slurries are 6.5ph and 400ppm. Im in late veg and I cant get lights over 250ppfd. I turned them up to 300ppfd and this is what happensView attachment 1263036View attachment 1263037View attachment 1263038
NiceAs you increase light, plant processes increase.
Photosynthesis (assuming you have CO2 and H2O present in sufficient qty 6CO2 + 6H2O → C6H12O6 + 6O2) CO2 yes, H2O good?
Respiration
Other stuff
I think you might be looking at an issue in the root zone that is exacerbated and only shows up with higher respiration.
Also your RH is a bit high making VPD a bit low, meaning the stomata are open but there is so much water in the air that there is not good gas exchange. If you increase the lights, temp goes up meaning RH goes down, VPD goes up, so respiration is restored. In that scenario, if your nutes were out of balance or not enough O2 in root zone, it could look like this and it is not really PPFD doing it, but rather the higher leaf temps and lower RH.
I'm thinking that if your VPD was on point and your watering / nutes / root zone oxygenation was all perfect you could bring that light way up.
It's a friggin balancing act man.
TLDR - I think the problem is actually in the root zone.
Too many words used. What is meant by all that is when you bring lights up, weak spots in your grow surface.Nice
No moe, you are fine, that’s the information I’m looking for.Too many words used. What is meant by all that is when you bring lights up, weak spots in your grow surface.
No i water when the soil is dry enough usually every other day or every 2 days.Hope you aren't watering soil like this.
What chart are you using apprently the one im using is way off? It says if room temps 82 stay between 65% and 75% for late veg early flower. Do you have a better chart I can snag from ya? thanks.I dont know what calculations you are using but it most certainly does NOT put you at 0.8-1…. It puts you at 0.48 and thats NOT ok
82 air under LED give a leaf temp of maybe -4 air temp - really need leaf temp for this equation. But assuming 82-4 = 78 leaf temp and 72 RH = leaf VPD of .59 kPa At this stage you should be hovering around 1.What chart are you using apprently the one im using is way off? It says if room temps 82 stay between 65% and 75% for late veg early flower. Do you have a better chart I can snag from ya? thanks.View attachment 1263542
In this thread there is a calculator app link, or follow the directions i posted to make one, Or use this one.What chart are you using apprently the one im using is way off? It says if room temps 82 stay between 65% and 75% for late veg early flower. Do you have a better chart I can snag from ya? thanks.View attachment 1263542
Ok see this chart on the top left it says leaf cooler than air temp by 1f. Well you leaf temps are likely about 77-78f which would be a difference of about 4-5f cooler as is typical under LED. I cannot stress how much difference leaf temps make in this equation.What chart are you using apprently the one im using is way off? It says if room temps 82 stay between 65% and 75% for late veg early flower. Do you have a better chart I can snag from ya? thanks.View attachment 1263542
And as respiration goes up, leaf temps drop as the water acts as a cooler. Its not a set it and forget it thing. If you drop RH and respiration increases, the delta between air temp and leaf temp also goes up.Ok see this chart on the top left it says leaf cooler than air temp by 1f. Well you leaf temps are likely about 77-78f which would be a difference of about 4-5f cooler as is typical under LED. I cannot stress how much difference leaf temps make in this equation.
No. leaf temps drop.U mean leaf temp will b closer to air temp moe?actually im confused
Most underrated tool for growing and its cheap.Im going to get an ir gun today so i know whats going on.ive been winging it for 2 yrs lol.ive finally got rh down between 44%-50% .air temps set at 26.4 extraction fan comes on at 26.7..im bit past mid flower at 5 weeks since bud onset .lights at 21" to canopy
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