Humidity levels in flower?

[LeastExpectedGrower]

"There is a prevailing consensus that 75 °F is the ideal ambient temperature to grow Cannabis under HPS lighting without CO2 supplementation. This experimental result indicates that an 84 °F ambient air temperature is required to achieve the same optimal leaf surface temperatures when using plant-optimized LED lighting-- and that a 75 °F ambient air temperature with LED lighting would not achieve optimal leaf surface temperatures, slowing metabolic rates and leaf and flower production."

If you want more articles you could find them yourself hps and leds are a whole different style of growing every factor humidity or temps air flow and the ways even wind hits the plants might affect (leaf surface temps) that's why I say using your IR gun measuring at the canopy is more true than ambient temps.... many people run into issues they never would think of as not over watering but plants exhibit sign of over watering like wilting could be lack of oxygen to the roots because not enough perlite and takes too long between watering which could also deplete nutrients in soil or not enough Transpire through stomata due to low surface temps and poor exchange of c02& oxygen

Is there a reason you're quoting me then saying exactly what I said?

 

[westcoast420]

I let it jump, 90+ degrees 80 to 85 rh supplimented co2 in 4x4 with 9 8g Lit Farms georgia runtz, 70 day veg, filled tent full. No pm, no budrot. Damn good run for me. Crispy leaves but bud was sweet and skunkier then l suspected. Pots then stalks followed by a few feet of canopy then colas to the light. No room for me to raise light View attachment 5131928

Dude those are absolutely scorched. You probably lost 75% of your thc content with that heat.

 

[Alfadog#1]

Most of the time canopy is 3-5 degrees hotter than ambient room temps due to being right under the lights no reson unless your beating your plants with wind it shouldn't be under ambient temps.... so if you only have your room around 78 example 81-83 isn't enough some plants are more tolerable than a other's push them untill they exhibit slight stress and back off from that. But yes I agree hps naturally heat up canopy much more than leds and lack of uv and infrared compared to hps makes photosynthesis that much harder for leds to penetrate

 

[VincenzioVonHook]

Just here to vent about humidity, saw the word on my screen and needed to fly into a furious rage. Don't worry lol...you can't be doing worse than me...plants starving and we have the worst humidity here atm. It's been 95-100% constantly for two weeks and raining like all hell. We got over 1000mm rain in two days... even with the dehumidifier running it doesn't get below 80-85% and sitting at around 90f in the tent. If I close the windows to help with dehumidification it gets too hot lol...no winning here.

Luckily no issues yet bar the heavy yellowing. Medium pH is good at 6.4, it's getting top dress of coconut, kelp and EWC every five days, and it's getting like an EC of 2.5 of liquid compost on top of that every few days.


Just waiting for the mould to creep on. Just be thankful your not me lol. I'm struggling worse than the plant in this humidity. Hope it hangs in there for another four or five weeks. I know I won't.

 

[Alfadog#1]

This is a live reading of ambient room temp and humidity and the canopy temp on the infrared gun

 

[FirstCavApache64]

View attachment 5132722View attachment 5132723
This is a live reading of ambient room temp and humidity and the canopy temp on the infrared gun

What kind of lights and what distance from the canopy? If led, how many watts are they? Just wondering because if they're led I'm gonna say either the temp gun needs to be calibrated or something else is going on. Physics is still physics and the leaf surface temperature will be cooler than the air temperature in an led lit tent unless you have lights burning them up from radiant heat or bad air movement or other environmental factors. I'm not saying your numbers don't show that but it shouldn't be showing that. Either your equipment is wrong or your environment.

 

[LeastExpectedGrower]

What kind of lights and what distance from the canopy? If led, how many watts are they? Just wondering because if they're led I'm gonna say either the temp gun needs to be calibrated or something else is going on. Physics is still physics and the leaf surface temperature will be cooler than the air temperature in an led lit tent unless you have lights burning them up from radiant heat or bad air movement or other environmental factors. I'm not saying your numbers don't show that but it shouldn't be showing that. Either your equipment is wrong or your environment.

I believe he's using HPS rather than LED which accounts for the LST being higher than ambient. Either way if your LST is +3 and your ambient temp is 85+ regularly, you're moving outside of optimal temperature range.

 

[VincenzioVonHook]

I believe he's using HPS rather than LED which accounts for the LST being higher than ambient. Either way if your LST is +3 and your ambient temp is 85+ regularly, you're moving outside of optimal temperature range.

i don't think they make purple HPS. IDK, Maybe i've just smoked way too much weed.

 

[LeastExpectedGrower]

i don't think they make purple HPS. IDK, Maybe i've just smoked way too much weed.

Phone cameras do funny things...if its LED, then yeah, that thermometer probably needs calibration.

 

[VincenzioVonHook]

Phone cameras do funny things...if its LED, then yeah, that thermometer probably needs calibration.

Phone cameras can definitely be misleading...if I take a photo under the lights, my plant looks dead . If I move the plant out the tent it looks its got a few days life left lol. Kinda crazy how big a difference it can make.



This is the exact reason they tell you to take pics in natural light. It looks even healthier under sunlight with the phone. Crazy how the camera works, By my eye it looks the same in all light.

 

[LeastExpectedGrower]

Phone cameras can definitely be misleading...if I take a photo under the lights, my plant looks dead . If I move the plant out the tent it looks its got a few days life left lol. Kinda crazy how big a difference it can make.
View attachment 5132759

View attachment 5132755
This is the exact reason they tell you to take pics in natural light. It looks even healthier under sunlight with the phone. Crazy how the camera works, By my eye it looks the same in all light.

In all honesty, I wasn't paying any attention to photos posted along the way...just the discussion.

 

[Alfadog#1]

What kind of lights and what distance from the canopy? If led, how many watts are they? Just wondering because if they're led I'm gonna say either the temp gun needs to be calibrated or something else is going on. Physics is still physics and the leaf surface temperature will be cooler than the air temperature in an led lit tent unless you have lights burning them up from radiant heat or bad air movement or other environmental factors. I'm not saying your numbers don't show that but it shouldn't be showing that. Either your equipment is wrong or your environment.

1000watt led hanging at 30inches aprox 850-900ppfd and I have full control over the environment (I bring up ambient temp to have canopy temp at 86) very simple as you said physics is physics I set my parameters to achieve the results I want did you know also well hydrated plant or possibly over watered can bring down LST dr.bugbee gave an example compare a wet and a dry towel on a counter in the sun which will have a cooler surface temp?.....the wet one. A We'll hydrated plant is the same so many factors but the point is (forget ambient temps go by canopy you will be much more satisfied) try it and come back in 2-3months and we will talk

 

[ComfortCreator]

need par meter?

Phone app is fine for general readings.

 

[FirstCavApache64]

1000watt led hanging at 30inches aprox 850-900ppfd and I have full control over the environment (I bring up ambient temp to have canopy temp at 86) very simple as you said physics is physics I set my parameters to achieve the results I want did you know also well hydrated plant or possibly over watered can bring down LST dr.bugbee gave an example compare a wet and a dry towel on a counter in the sun which will have a cooler surface temp?.....the wet one. A We'll hydrated plant is the same so many factors but the point is (forget ambient temps go by canopy you will be much more satisfied) try it and come back in 2-3months and we will talk

You also say your canopy is warmer than ambient throughout this entire thread so I'm guessing your plants are too dry/under watered according to the good Dr Bugbee? My and everyone else's leaf temps are cooler than ambient air temperature so I'm guessing that our plants are well hydrated and healthy just like I've been saying. There's something wrong if your LST is higher than ambient air temperature. I don't think I'll need to come back in a couple months, I'll just keep doing things my way scooter. I'm going to just drop this, I've derailed the OPs thread enough arguing with a guy that calls himself an Alpha then posts evidence of why he's wrong.

 

[Alfadog#1]

The name I used is "alfa" not "alpha" not for the same purpose maybe your illiterate but I apologize iv ran out of time myself and don't have the crayons to explain it to you again but hopefully somebody could talk slow and use simple words

 

[FirstCavApache64]

The name I used is "alfa" not "alpha" not for the same purpose maybe your illiterate but I apologize iv ran out of time myself and don't have the crayons to explain it to you again but hopefully somebody could talk slow and use simple words

If you're going to accuse me of being illiterate at least use proper grammar while doing it genius. It's you're as in" maybe you're illiterate". I've, not iv and I have quite an acceptable vocabulary. I understood the spelling of your chosen username, I also understand there's been plenty of other people just like you that think they know it all because they watched a couple videos and hung out on Reddit. They like to think they're Alpha this and Alpha that too so most of the user name variations are probably taken up by now by posers like you. You posted one pic of a grow with a scrog that had no real purpose other than I guess to support some buds and now you're talking shit? Oh yeah, nice blurple 1000 watt LED.

 

[Budzbuddha]

1000watt led hanging at 30inches aprox 850-900ppfd and I have full control over the environment (I bring up ambient temp to have canopy temp at 86) very simple as you said physics is physics I set my parameters to achieve the results I want did you know also well hydrated plant or possibly over watered can bring down LST dr.bugbee gave an example compare a wet and a dry towel on a counter in the sun which will have a cooler surface temp?.....the wet one. A We'll hydrated plant is the same so many factors but the point is (forget ambient temps go by canopy you will be much more satisfied) try it and come back in 2-3months and we will talk

1000 watt led ?????????

must be a Blurple unicorn running around somewhere

 

[Mont@n@]

Grow based of your Vapor Pressure Deficit (VPD)

VPD Chart
https://cerescann.com/an-introduction-to-vapor-pressure-deficit/

View attachment 5131779
25 cxb3590 at 1250 watts 5x5
My flower room temperature
80.6f - 82.4f (mini split a/c, CO2 700ppm)

My safe zone RH% with air circulation based on that chart is:

RH% VPD (kPa)
85% - 0.54 Fungal Pathogens
80% - 0.71 MAX (big chance of fungal)
75% - 0.89 x Safe Zone Max
70% - 1.07
65% - 1.25
60% - 1.43
55% - 1.61 x Safe Zone Min
50% - 1.78 Min
45% - 1.96 High Stress Zone

I hope it helps and by the way this chart hasn’t failed me good luck
Happy growing

Basically this is how I dial in my rooms environment and how I understand the chart. Humidity will dictate your room temperature or more like based on your humidity you have to choose your temperature.

With my RH% of 60-75%, my ideal temperature based on that chart is between 80-84 maybe 86f

There is a lot of scientific info on Google about plant water vapor release and co2 intake but thats when VPD gets more complicated.


happy growing