Grow Room Lights On 6 pm to 6 am:
Daikin A/C keeps the humidity in range 60-70%
Grow Room Lights Off 6 am to 6 pm:
Central A/C at 75f, keeps my 3bdr house humidity around 65-68% and 800ppm co2 concentration. (1 person breathing in it)
4” passive intake: passive intake with a 4” belimo damper(guest room is my lung room, dehuey in lung room for winter and rainy days)
4” exhaust to the outside environment:
4” Can-Lite Filter 9000, 5” S&P TD-125, 4” white ducting, 4” belimo damper, vent dryer.
During lights off;when my humidity hits 73%, my in-line fan will turn on and both dampers will open until it reaches 68%rh, by the time the dampers are fully closed (90sec) it will reach 67 or maybe 66% depending of the outside environment.
Grow room controller: My rooms are controlled and monitored 24/7 by thegrowtronix system.
Driver: 5 HLG-240H-C1400B
I test the Led drivers @ 110v and 220v with a temperature gun, A/C on and with the oscillating fan off. Temperatures @ 110v where 144f, ouch. The 220v where 113f and now with the circulation fan on, the temperature sit around 98 -102 degrees.
System: Aero/NFT 18 plants, 75 gallon reservoir with 55 gallon of RO water at 0ppm, 150ppm DIY cal mag Plus, 1mL of southern ag friendly fungicide and DIY hydroponic nutrients.
Reservoir temp: 76-81f, your system and Res has to be light proof to avoid brown algae and root rot.
Co2: Lights ON ONLY
350ppm min and 750ppm max
When co2 drops below 350ppm my inline fan will turn on and the dampers will open to bring co2 from my lung room, it only takes between 3-5 minutes to go from 350ppm to 750ppm and it takes 30 minutes to go back down to 350ppm.
pH: My pH drift between 5.4 - 6.2, out of that it gets corrected back to 5.8 the sweet spot.
This is how I control vapor pressure deficit and dial in my rooms using VP(air). Growtronix only reads Water Vapor in Air or VP(air) I adjust Temperature based on my room Relative Humidity (RH%) to maximize plant transpiration. You will have to add co2 enrichment later on to get better results. imho this is the proper way to maximize co2 in a grow room but that’s another long ass scientific story.
It is thought that transpiration enhances nutrient uptake into plants. Carbon dioxide entry: When a plant is transpiring, it’s stomata are open, allowing gas exchange between the atmosphere and the leaf. Open stomata allow water vapor to leave the leaf but also allow carbon dioxide (CO2) to enter.
My flower room (aero/nft) relative humidity it’s around 60-70%. my safe zone temperature based on the chart is 80-82f.
Here are my numbers from the chart:
80.6f - 82.4f (mini split a/c, CO2 750ppm)
My Relative Humidity with air circulation: Growtronix VPD Sensor (Room Temp + Humidity = VP(air)
To put it as simply as possible, VPD = VP(leaf) – VP(air). The calculation for VPD only requires three variables, leaf surface temperature, air temperature, and relative humidity.
Peter at Pulse <[email protected]>
So you probably already know VPD is important. VPD impacts stomatal opening,
CO2 uptake, transpiration, nutrient intake, and plant stress.
To make a long story short, tracking VPD is essential to grow room success.