nachooo
Well-Known Member
I think the same happened to me but by chance...
unknowing the real reason
How many umols for fllowering?
- Thread starter Porky101
- Start date
unknowing the real reasonThought 40-50% flowering max humidity ?
Humple
Well-Known Member
Not at the higher ambient temps most LED growers end up running.
Rocket Soul
Well-Known Member
Some use that as a rule to avoid budrot and pm, airflow and prevention can let ypu go higher, but most people trim back humidity towards the end anyway. VPD can guide you a bit, to see where to go when things dont grow right due to environment, but its no 10 commandments.
Randomblame
Well-Known Member
Yeah, thats the recommedation for 25°C/HPS but with LED we need aroud 30°.
40-50% is what I'm looking for at night. Over the day it doesn't matters if it's more.
In order to prevent bud rot/boitritis the moisture transpired by the flowers must completely evaporate during the day(every day). If this does not happen the moisture weakens the cell tissues and gives bud rot easy access. But the evaporation usually also happens with 60-70% RH over the day with some air movement.
Sometimes if I have particularly compact and fat buds I put 2inch short pieces of McDonald's straws in the interstices of the buds to allow air to enter the interior and ensure that transpired moisture can evaporate completely over the day.
Looks crazy, like buds with paploots curlers, lol!... but it works!
InTheValley
Well-Known Member
Some strains tho are different. The key to a great VPD is the leafs prying. When you see that happen, simply write down your RH and Temp, That is your VPD goal.
I know mine like 80F and 49RH, PER MY METER, which I dont know if is right. Cheapo. When those numbers are hit, like clockwork, they pray, no matter time of day.
I know mine like 80F and 49RH, PER MY METER, which I dont know if is right. Cheapo. When those numbers are hit, like clockwork, they pray, no matter time of day.
Randomblame
Well-Known Member
Hey Seth!
Finally I've found the article about the leaf temps. They don't specificate an optimal leaf temp for cannabis but you can see the differences in a few flir cam pics. But if it's -1, -2 or even -3° could still be within the error range of the measuring device. IR thermometers are not that accurate and they show only the hottest spot and not the average LST.
https://www.blackdogled.com/lst
Randomblame
Well-Known Member
No wonder they pray all day long... you intuitively choosed the right conditions.
80°F and ~50% RH would be a VPD of ~1,3mbar or kPa which is good for the early/mid flowering stage. In the last few weeks when the tops gets more and more weight up to 1,5mbar would be okay.
It's the time with the highest nutrient demands anyway and instead of increasing the ppm value you can just let them sweat/drink more. The dangerous zone begins above 1,6...
that's why i measure with a thermocouple, even IF there is an error in range, when i measure BOTH leaf AND ambient temperature with the same device i should be still quite accurate to measure the correct delta
Rocket Soul
Well-Known Member
Sounds interesting, can you develope on what meter you use? Maybe a link
Randomblame
Well-Known Member
HydroFood
Active Member
Has this cheap thermocouple proven well for you? Pretty accurate? Can you use different/better thermocouples with the meter?
Sorry to dig up old thread.
Sorry to dig up old thread.
Airwalker16
Well-Known Member
Bigclivedotcom uses that one
BCBLondesLEDGrowLights
Well-Known Member
I like to run no less than 1000 up to 1500ish. With c02.
HydroFood
Active Member
I Hope that’s a good thing!
Iv seen that name mentioned quite a few times.
Iv seen that name mentioned quite a few times.
Bigclivedotcom uses that one
Keesje
Well-Known Member
Older thread I know... but I found this interesting clip on You Tube
TM-902C K-TYPE THERMOCOUPLE AND THERMOMETER REVIEW
The guy bought 4 identical devices, and with thermal paste he glued the sensors on a aluminium plate.
Every device gave a different result: Values ranging from 18 to 20.4 Celsius.
Of course when you measure both the room and the plant surface with the same device, you will know the difference in temperature, but you still will not know what the temperature exactly is.
Or you must find a way to calibrate your YM-902C.
Or determine the temperature in your room with another - reliable - thermometer.
TM-902C K-TYPE THERMOCOUPLE AND THERMOMETER REVIEW
The guy bought 4 identical devices, and with thermal paste he glued the sensors on a aluminium plate.
Every device gave a different result: Values ranging from 18 to 20.4 Celsius.
Of course when you measure both the room and the plant surface with the same device, you will know the difference in temperature, but you still will not know what the temperature exactly is.
Or you must find a way to calibrate your YM-902C.
Or determine the temperature in your room with another - reliable - thermometer.
for the correct air temperature i use the sht31, i reviewed it here, thermocouple is only for the delta