Opinions about Growhub for Indoor grow in 3x3x6 tent

I’m in Missouri USA where it’s 68-72 F with 30-35% humidity in the room where I’m growing. I have my AC Infinity 300watt LED, 2 small humidifiers and 180 CFM exhaust fan running from the growhub. I’m running a one week test right now to make sure it’s maintaining decent environment :slight_smile:

Basically I’m trying to figure out the best config choices to get the tightest VPD/Humidity/Temp because at this time they swing more than I’d like. That being said, I’ve gotten the config to the point where I can keep the RH & Temp to within a few degrees which is MUCH better than I was doing manually but I had to reduce my exhaust fan speed to get there :slight_smile:

Can someone explain more detail about how recipes are run? For example, if I choose RH & VPD, I’d expect Growhub to care far less (or not at all) about the temperature and instead focus RH/VPD, etc.


I’ve had the best results honing in on the environmental element that is most problematic. Since in your case it seems that element is relative humidity, I’d start with the average temperature in the tent (ideally the leaf temperature measured with an IR thermometer and adjust the offset in the Niwa settings) and VPD. Get the VPD that you want for the temperature and the app will calculate the appropriate RH. Then let the humidifiers take care of it. VPD is the combination of temp and RH so the Niwa won’t favor one over the other but it will try to adjust whatever element is taking the environment out of the target zone. Another thing I’ve found is that with humidifiers inside the tent, I don’t need to manipulate the exhaust fan much once the the environment is dialed in, assuming that the temps outside the tent aren’t wildly different than those inside. Hope this helps!

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Nice, thanks and I’m testing setting T & VPD now, still waiting for infrared thermometer to show up tomorrow.

I’m curious if growhub processes differently if you choose T&VPD versus T&RH, RH&VPD?

Also what type of range should I see for leaf offset?

Thanks again for the advice!

Great! I don’t think the Niwa processes things any differently once you have the temp/RH/VPD set up, those are just to get your targets locked in. As for leaf offset, I believe that mostly depends on how bright and close your lights are. In my case, with LEDs, and depending on the growth stage, that can be as much as -5F and as little as -1F.

One thing that I’ve noticed is that if I’m having to control a particular part of the environment regularly (like constantly lowering the humidity), overshooting the target a bit can help get to the VPD you want. Check the stats in the app to see the ranges and averages. Good luck!

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