Inkbird Environment Control Automation - VPD Made Easy!

[NezA]

Right as promised over in my grow diary here's a post about my Inkbird environment controllers. I have the IHC-200 WiFi humidity controller and the ITC-308 WiFi thermostat, I managed to get these for a steal at 50% off but full retail price these go for ~£100 which makes them significantly more affordable than many other environment controllers on the market.

 

I'm using these devices to control my VPD and I have to say I'm extremely impressed. Both my temps and humidity have been extremely stable. Thanks to these devices not only are my temp and humidity perfectly stable, but both are being kept in the perfect range in relation to eachother, for optimal VPD.

So a little bit about how these work. Each controller has a probe sensor and 2 power outlets, one for a device to increase humidity or temp and one for a device to decrease humidity or temp respectively, depending on what you have each controller set to they'll automatically switch between the increase/decrease devices to keep the temperature and humidity within the desired range.

 

For example, for the humidity controller you could have a humidifier and additional extraction or a dehumidifier pugged in (or both with an extension.) When the humidity is too low it will run the humidifier until humidity hits the desired range then it will stop running the humidifier. If humidity starts to creep up it will run the additional extraction / dehumidifier until humidity is back where you want it. The same applies to the thermostat. Each device is only run when it is needed. 

 

There are basic versions of these controllers that don't have WiFi and for the budget conscious or non technical people they're potentially a good option, although don't think they'd offer the same level of precision when it comes to controlling your environment. But the WiFi version has an app that can be installed on a smartphone that's absolutely fantastic. The app itself allows you to remotely monitor and control both controllers independently from anywhere you have an internet connection. Which is a great feature in and of itself. However more importantly it has an automation feature that allows you to create rules for each device that can be triggered from the status of the other device or some other external factor.

What follows is a short guide as to how I have these devices setup and how I created rules that will trigger and adjust each device as my environment shifts the devices will adapt to compensate, keeping my VPD in the ideal range constantly.

 

Sensor placement. 
I placed my sensors at canopy level and far enough away from my heater and humidifier so that I'm getting an average reading rather than over indexing on any one reading. Obviously you know your grow space so make sure you're placing your probes in an appropriate location and that you're getting a good reading.

The trickiest part of the setup was getting the devices to register on my WiFi but after a couple of attempts we were in business. To be fair the app does a brilliant job of guiding you through the process and it's pretty straightforward.

 

Once they are connected and registered on your network you'll see each device listed in the app.

 

From here you can manually set the desired value for each device. I personally use temperature to drive my humidity and set the temperature value to 24.5c and my temperature range pretty much fluctuates between 24-25c consistently. On the odd occasion I have seen it as high as 27 and as low as 22. But I haven't seen those extremes for weeks now, not since I was initially dialing in the setup. Now everything is dialed in though it's extremely stable indeed. 

 

Creating Automation Rules

 

Ok so to create a rule firstly we select the smart option at the bottom of the screen.  

 

Next select the automation tab.

 

 

On my screen you can see all my veg rules in green. Obviously the first time you see this screen it will be empty and rules will be added in the order you create them. To create a rule select the blue "+" icon in the top left. You'll then be presented with a screen that allows you to select what type of trigger condition you want to set. Because I want the devices to balance each other I chose the "when device changes status" option.

 

 

 

My temperature like many of you, I'm guessing, tends to be far more stable than my humidity. So I opted to have my temperature value drive my humidity value. So on the next screen we select our thermostat. (ITC-308-WIFI)

 

Here we're are presented with a list of options. I have used the "current temperature" parameter.

 

 

Each rule I have created is set at 1c increments. I also use the "<" (less than) condition I originally set this to "=" but as soon as the temp shifted by 0.1c the rule would cease to apply so using "less than" at 1c increments covers the entire range of decimals. Select the upper limit of the temp range you want to cover. 

 

 

On the next screen we need to select what we want to happen when those conditions are met. In this instance we want to run our humidity controller so select "run device" 

 

 

Now select the humidity controller (IHC-200-WIFI)

 

 

Next we want to select what we want the humidity setting to be, so select the "Setting Humidity" option. Use the slider to get in the right range if you want to be really precise you can use the + and - icons to make fine adjustments.

 

 

Here you'll want to refer to a VPD chart to select a humidity value that's appropriate for the temperature threshold you have selected for this particular rule. The rule we are creating is for flower so I have used the appropriate settings assuming a -1c leaf temp offset, these values will give us a RH of 51% between 24-25c

On the last screen you get a summary to review before saving and activating the rule.

 

 

So for this example we are using <25c as our threshold temp. So to recap what we have said to the app is "if the current temp on our thermostat is <25c then set our humidity to 51%" now where this gets really interesting is that you can stack the rules up so if I set a <26c rule for 53% humidity we have now told the app 2 things:

"if the current temp on our thermostat is <26c then set our humidity to 53%, unless the current temperature on our thermostat is <25c then set our humidity to 51%"

You can then add additional rules for <24c etc etc and you continue to stack these rules one on top of the other until you cover your entire temp range and a couple of c either side just in case.

 

There's a whole heap of other options I'm yet to explore with this but just this functionality alone for the price is pretty fantastic. Yes there's quite a bit of setup involved but once it's done and your rules are saved you never have to look at it again other than activating or deactivating the rules for the various growth stages. 

 

At the moment I only have a complete set of rules for veg setup. By the time I flip I will have created a full set of new rules for optimal flower VPD. You can colour code the rules so you can easily see at a glance which rules are for which stage my and you can activate and deactivate any given rule using a toggle. So when I need to, I can just switch between different rule sets easily and there's no need to recreate rules from scratch all the time.

 

 

If people find this post useful I might explore some of the other features in the app and make additional posts over time.

 

Keep it green

 

-NezA

Edited October 13, 2020 by NezA
Missing image

[jtoogood]

Like your work mate, I'm running inkbird gear too - just the IBS-M1 with 2 ITH-20R-O temp/hygro measures. These don't actively manage power, thinking I've made a mistake by not getting the power plugs like yours. I do have some smart plugs that I'm going to set timers for as I now have a good profile for when I need to turn on heating for lights out and fan schedules.

 

Soz to hear about your pal. Without giving much away, I can probably answer a lot of Qs re the big C, so if there's any questions you may have, I may be able to answer. PM if so (I can't send any to you atm, think I'm not ranked high enough yet).

Edited October 13, 2020 by jtoogood

[NezA]

Cheers @jtoogood I've got some experience but always willing to learn from others when you get to 50 posts drop me a message if you remember 

 

As for this setup I really can't fault it definitely worth the upgrade if you have the funds to spare. It's taken a lot of agg out of adjusting rads and extraction for me everything is perfectly balanced all the time. I'm in a loft so my environment normally suffers significant fluctuations depending on weather so I was forever faffing about in order to get things right. This is a god send hahaha

 

Keep it green

 

-NezA

[jtoogood]

Just now, NezA said:

Cheers @jtoogood I've got some experience but always willing to learn from others when you get to 50 posts drop me a message if you remember 

 

As for this setup I really can't fault it definitely worth the upgrade if you have the funds to spare. It's taken a lot of agg out of adjusting rads and extraction for me everything is perfectly balanced all the time. I'm in a loft so my environment normally suffers significant fluctuations depending on weather so I was forever faffing about in order to get things right. This is a god send hahaha

 

Keep it green

 

-NezA

Cheers pal, ahh I see, I need 50. Better start now. Likewise if you think of anything treatment related, that's my line of work.

 

I'm getting temp fluctuations between 19 and 30, but normally can intervene before the temps go much higher.  I need to find somewhere to vent better, as I don't have anywhere to suck cool air from in my shed. Anyway, loving the inkbird apps, nice and easy control. Could I ask what you paid for those bits of kit? 

 

Cheers. 

[NezA]

@jtoogood Noted, I'll definitely pick your brains for sure. Waiting on the results of biopsy at the moment so prognosis isn't clear yet. But he has been told terminal as it's in his muscles and spread all over now.

 

Back on topic,

They're on that big river bookshop as a bundle package for £98 at the moment. It's showing me a 20% off voucher on them currently so just under £80 for the pair. Offers come and go the tipping point for me was when I saw a 50% off voucher I paid £53 I think.

 

The WiFi thermostat you can get on it's own for just over £30 on a deal today as well.

 

Can't sing their praises enough.

[sweettooth]

Im using the inkbird 308 wifi too, great that I can adjust the temps from anywhere in the world. I wonder if your smart rules are a but complicated though?? I use the automation rules instead of smart rules and Ive only got 4 -

 

Veg Light on

Veg Lights off

Flower lights on

Flower lights off

 

My humidity is controller by a12L dehumidifier which is set to RH of 50 and will kick in if the RH rises or go to standby mode when the RH is 50 or below

 

The automation rules are for "any condition is met" and use the schedule function to start at the beginning of my lights on or off period. The task is my itc-308 temp setting - light on is 32 and lights off is 22.  Effective period is the time span of my veg or flower period. I set the period to finish 2 mins before the next period stars. Ive had to play around with the heating hystersis temp and cooling back temp settings but have my heating difference at 0.8 and my cooling back at 1.8 although I've just switched to a sealed tent with co2 so dont have the cooling relay rigged upto anything as my highest temps are now stable and dont need to cool as i dont want to extract any co2.

 

Heating wise Im using a 3kw fan heater mounted at the top of the tent which is only set to 1.5kw. Ive got some current setup pics on a thread in Environment - managing co2 and temps.

 

My temps during the lights on now sit at 32 constant as im not extracting, before though they would only fluctuate by 1.5 degrees lights on and 2 degrees lights off

 

Great post though and if your current rules work for you then dont change, I tried with the smart rules for ages and moved over to automation as I found it was much easier to manage and with only 4 rules, I can easily change them when the seasons change which often affects my growe due to the location

 

  

[Shumroom]

Excellent detailed description of how to set these up.

 

I will definatley be referring back here 

 

Can this be pinned please?

 

 

Edited October 17, 2020 by Shumroom
Eta

[NezA]

7 hours ago, sweettooth said:

Im using the inkbird 308 wifi too, great that I can adjust the temps from anywhere in the world. I wonder if your smart rules are a but complicated though?? I use the automation rules instead...

 

For a ball park "these settings are ok" type of control the way you have it setup is definitely easier and will do a great job.

 

The reason I opted for this more complex setup is because my aim is to achieve optimal VPD, (well to the best of my ability at least,) for the entire duration of the grow. If your VPD is at the right level throughout the entire grow cycle, your plants will be transpiring at maximum efficiency, constantly. Plants are biological machines and by providing the right environment we are helping those machines perform their absolute best. So by achieving optimal VPD and getting the plant to perform at its absolute maximum efficiency, I am unlocking the true genetic potential of the plants themselves. It's the difference between providing a great environment and providing the best possible environment.

 

So using your setup an an example let's say during flower, 32c lights on (this is a little high for my liking. But you're sealed Co2 so can get away with slightly higher temps, but I'd still prefer under 30c myself) to achieve optimal VPD you'll need a humidity of 66%, but then when your lights turn off your temps drop to 22c your humidity needs to drop to ~44% for optimal VPD. I try to avoid big swings because big swings take longer to correct. Meaning your environment is unstable for longer. For every +/- degree C shift in temp there should be about a +/- 2% shift in RH. Over the course of a lights on lights off cycle running a fixed 50% RH your setup will only achieve optimal VPD when your temps are at ~25c, For example, if you're only at 25c for half an hour while lights warm up and another half an hour while lights cool down you're only achieving peak transpiration, and therefore peak transportation of nutrients and resources, for one hour in 24. 

 

During veg to achieve optimal VPD with 50% RH your temp range would need to be ~19-20c which is way too low for me. This is why I'm running approx 60% RH. Because I need my temps in the 24 - 25 c temp range to keep my plants happy whilst in veg. So I add more humidity to keep transpiration at maximum for the higher temperatures I need. The inverse is also true and if you're struggling to keep humidity down you can increase temperature to offset it. If the plant is able to transpire effectively running a higher humidity during flower is entirely possible.

 

If you want to know where I'm getting these numbers I'm using the VPD chart published by Pulse. My table was calculated with a -1c leaf temp offset. Which is about right but I need to invest in an IR thermometer to do this properly.

 

It should be noted that during different stages of growth a different VPD is required. For each stage your VPD value should be:

 

Clone/Seedling 0.7 - 0.8

Veg 0.9 - 1.0

Flower 1.3 - 1.4

 

I'm not presuming to tell anyone this is the only way to do it. It's just the path my own research has led me down. If people are interested to hear more I can expand the scope of the thread to include more detail about the topic of VPD generally

 

 

[sweettooth]

this is right up my street and I will do some in depth reading. ive started reading about the right amount of oxygen to the root zone,  especially in  sealed rooms and the detrimental effects of ethylene. im constantly tweaking things and agree that growing is a true science as well as an art, not just about throwing a light in and sitting back. I will certainly check out VPD and see if I can incorporate it into my environment. Interesting in following some of your grows

[sweettooth]

I've just checked out that pulse page. can't believe I need to be running nearly 75% RH at 31 degrees..  surely I'd get bud rot running those humidity levels during flowering??? Defo bedtime reading involved here. 

[sweettooth]

just been checking my area and my vpd isn't too far off. as my dehumidifier is around light level, the RH at canopy level is a lot higher than what my dehumidifier says the RH is. Ive got an aircomfort monitor at canopy level. where do you place your dehumidifier and what you using? if the inkbird is managing the on off of your dehumidifier,  I'm assuming the RH level of your dehumidifier should be set low so it doesn't interfere with the inkbird control??? my dehumidifier is pretty basic. 12L probreeze but does the job but will need to set the RH slightly higher on the unit to raise the vpd at my canopy level. im a nerd and love this level of technicality 

[NezA]

@sweettooth

 

I've got a diary up at the moment mate feel free to check it out. This is my first dabble into the world of VPD. 

 

Give this a watch mate it's interesting stuff

 

 

Here are the VPD Charts I'm using for reference:

 

 

 

 

 

Edited October 17, 2020 by NezA
Add VPD Charts

[sweettooth]

I'm too scared to test having high RH during flowering

 

maybe up to week 5 but after that I need it in the low 50s for my sanity and the ability to sleep comfortably hahaha

 

will try it though. always looking to create the best environment for my girls. environment = nugs. 

 

saving those charts!!!!!

Edited October 17, 2020 by GSZZ

[NezA]

3 minutes ago, sweettooth said:

I'm too scared to test having high RH during flowering

 

maybe up to week 5 but after that I need it in the low 50s for my sanity and the ability to sleep comfortably hahaha

 

will try it though. always looking to create the best environment for my girls. environment = nugs.

 

saving those charts!!!!!

 

Fixed that post for you. 

 

But yeah I know the feeling hence why I'm shooting for a temp of 24 - 26 meaning my RH will be in the 50's where I'm comfortable.

[sweettooth]

whoops. thanks.

 

I've changed up my lights off period to step down the temps over 2 hours so its not a massive jump using a 3 stage automation,  hopefully the RH will follow suite. From what I've been reading, adding co2 is only beneficial through the first half of flowering so will probably look at stopping the co2 and reduce the temps so I can bring down the RH towards the end and keep in the vpd sweet spot. First time with co2 and sealing my area so time will tell. May look at the inkbird humidity sensor and swapping my dehumidifier