Looking at a VPD chart it says for a good VPD @ 77 degrees I should be around 70% humidity. From what I read elsewhere that is too high. This confuses me. chart link
Grow Room VPD humidity question
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Basic parameters are....
Veg humidity should be 50 to 70 percent
Flowering humidity should be 50% to 60%
End of flowering humidity should be 40%
Veg humidity should be 50 to 70 percent
Flowering humidity should be 50% to 60%
End of flowering humidity should be 40%
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To properly measure VPD you need an infrared temperature gun to take readings on the leaf surface itself. Heat and humidity affect the stomata underneath that help with c02 exchange and transpiration.
Vapor Pressure Deficit VPD Calculator - Dimlux Lighting - The Best Grow Lights
Vapor Pressure DeficitCalculator Calculate both Room VPD and Leaf VPD automatically Just enter the value below to generate the VPD values for your room and your plants. You’ll need to know the room’s temperature, relative humidity, and the plant’s temperature. We recommend calibrating your...
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Weed is Weed. It'll find a way to live. The closer you get to Autowonder's suggested parameters, the better weed it'll be.
I did that. my leaf temp is +1 in most places and +2 in a couple. the chart still lists a rh of 70% at 73 degrees. Far above what others state.To properly measure VPD you need an infrared temperature gun to take readings on the leaf surface itself. Heat and humidity affect the stomata underneath that help with c02 exchange and transpiration.
Vapor Pressure Deficit VPD Calculator - Dimlux Lighting - The Best Grow Lights
Vapor Pressure DeficitCalculator Calculate both Room VPD and Leaf VPD automatically Just enter the value below to generate the VPD values for your room and your plants. You’ll need to know the room’s temperature, relative humidity, and the plant’s temperature. We recommend calibrating your...
^ hence my question. The VPD chart says way higher and does not distinguish between veg and flower.
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The chart does differentiate between the different phases of growth.
Here is a good article on VPD
If you can control your parameters within VPD you'll get better growth. VPD is a standard in Horticultural climate management whereas what you are referring to is a general guideline.
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I have grown in low humidity for a lot of years and the plants just keep doing their thing. Above my canopy, 9% - 12% humidity is no stranger. Currently I have no room in my tent for the humidifier. At least when its hot and I am running the grow room evaporative cooler, I can get 60% sometimes.
I see now. the chart I had didnt show the different stages of growth. Thanks.The chart does differentiate between the different phases of growth.
Here is a good article on VPD
If you can control your parameters within VPD you'll get better growth. VPD is a standard in Horticultural climate management whereas what you are referring to is a general guideline.
I use only sterile hydro with clorox, so this might not apply to all growers.
I've never had bud rot with humidity in the 60s, seed to harvest.
I've got a humidifier right now keeping a tent in the low 60s that will be harvested this weekend.
And another flowering tent at the 8 week mark with humidity around 65%.
Lower humidity modifications to the VPD chart for cannabis flowering convert the chart to something else, but it ceases being a VPD chart.
I've never had bud rot with humidity in the 60s, seed to harvest.
I've got a humidifier right now keeping a tent in the low 60s that will be harvested this weekend.
And another flowering tent at the 8 week mark with humidity around 65%.
Lower humidity modifications to the VPD chart for cannabis flowering convert the chart to something else, but it ceases being a VPD chart.
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