Inkbird Environment Control Automation - VPD Made Easy!

[growinggold]

We need uk420 infrared thermometer. Someone must be able to give us a steer here..

[superfruit]

Another nice quote from the BlackDogLED website:

 

Quote

High Pressure Sodium (HPS) in particular converts a significant portion of the energy consumed by the light directly to non-visible infrared light in the 810-830nm range, peaking about 819nm. This infrared light is perceptible to you (and plants) by the warmth it creates when exposed to the light. Additionally, much of the visible light HPS bulbs produce is yellow and not highly-utilized by plants. This radiation not used for photosynthesis or other chemical reactions only serves to heat up the leaves, requiring cooler ambient temperatures to keep the plants' leaves at their ideal temperature.

 

Edited January 21, 2021 by superfruit

[growinggold]

So about 4c difference

[superfruit]

1 minute ago, growinggold said:

So about 4c difference

 

And if you pop +4c leaf temp into one of those Pulse charts a really ambient low temp of 22c requires 80% humidity for a VPD of 1.2.  just feels wrong for some reason - 80% humidity will case a Carboair to lose efficiency, among other issues. 

Google isn't making life much easier

 

 

[growinggold]

Imo you want to put plus +2 in not +4. As the difference is from -2 not 0. ?

[superfruit]

37 minutes ago, mikeydoughnut said:

The crucial thing here is leaf surface temp. I hear its around 1/2 degrees below ambient air temp, i could be wrong

 

No trouble man i know the pressures of home schooling - quite the world we are living in!

 

I think previous discussions have been based on LEDs which give off much less heat, whereas my issue is the HPS bumps leaf temps up by around +4C

[superfruit]

On the plus side, I've just connected up the Inkbirds and sure enough I can see them working to meet the preliminary rules I've created. Impressive gear! Using an Android emulator I also get the data streamed to my PC too 

[superfruit]

@mikeydoughnut stick in there with the schooling, sounds like they're benefitting! 

 

I'm only in the very early seedling stage (just showing the cotyledon today. The 250w hps hung high is creating an ambient temp of 22c with the 4" rvk at 50% speed. The RootIt is keeping roots at 24c, and the Inkbirds keeping temp at 24c & rh at 63%. Clever these gadgets!

[zen-ken]

1 hour ago, mikeydoughnut said:

@NezA sounds like your journey is planned out. Wish i could be so organised. Good luck with the living soil n that. I like how its pretty much how nature intended but theres no way im having worms in my house!  

 

@superfruit this is what i learned, again, practically the other day. Cannabis can can consume ridiculous amounts of light energy. I believe its the far red spectrums in HPS that will generate the heat (uv). Have you got a fan speed controller? Try and use that to negate the heat generated by the hps. A cannabis plant can efficiently use upto 2000ppfd. This is assuming you are feeding enough and watering is bob on. You want to use as much light as possible whist controlling temps. So a combination of extraction and oscillation of air over the leaf surface could bring your temps and humidity down in one swing of the bat. The crucial thing here is leaf surface temp. I hear its around 1/2 degrees below ambient air temp, i could be wrong. Depending on you stage of growth it might not take much tweaking. If you're about to go into or in flower get those numbers down as best you can. 

 

I was watching a video on youtube and a lady said she understands the frigtening thought on budrot but if you follow the vpd and its in balance you should be good .... obviously 70/80% humidity isnt good but a bit above or below ideal isnt the end of the world.

 

Apologies if i mistook what you were discussing, my heads fried from home schooling.

2000ppfd is the absolute limit and that's with CO2.....the ppfd provides a very diminishing return as you take it over a 1000.

VPD is great in the first weeks....after week 4 of flower I would completely ignore it or ur rock hard buds will get bud rot ime.

 

Watch the Bruce Bugby video and you will see what I mean.

[zen-ken]

2 minutes ago, superfruit said:

 

Edited January 21, 2021 by zen-ken
Didn't read the post properly

[Shumroom]

Remember when looking at temperatures,

try to stick to either C or F,

don!t mix the two 

 

 

So +5F is really nearer +2 or 3 in C,

but it's not a linear scale so best to convert to the same scale.

 

Atb

 

 

[zen-ken]

Just now, mikeydoughnut said:

@zen-ken totally agree and respect your knowledge as it’s far greater than mine. 

 

In my own head thought perhaps rather than looking to change lights etc I’d first look to bring temps down by other means. Having said this I dunno what size hps he/she has and how much ppfd is being provided. 

 

However i do bow down to greater knowledge. I know me place  

I wouldn't say that Mikey.....your skills are easily catching up to mine.....I've just got more experience of mistakes is all....always feel free to question anything I say...u know I love a good discussion to get to the facts brother.

I'm no Bruce Bugby

 

 

[zen-ken]

Its only cause the suggested VPD at 60 RH is gonna cause mould.

Its right for growth.....just not good for rock solid bud 

[zen-ken]

Just now, mikeydoughnut said:

 I was lay in bed with Bruce the other day taking notes. I felt dirty 

 

That’s the thing we’re all here to learn and one of the best ways to learn is realising when others are right. See a lot of back and forth on here, even with established growers who can grow with their eyes closed.

I'd love to give Bruce's  method a crack....seems so simple.....peat, vermiculite, gypsum,dolomite lime etc.

No ph and just an EC meter.

Feed at 1.3 - 1.4 till the run off reads the same....massively difficult to over water....heaven.

 

I'm really struggling to import the blue powder tho....I looked into it and it was as much to ship as to buy....I was also worried it may be a banned fertiliser ie bomb making gear.....I'd be ruined if it got stopped at customs and they came to see that im a personal grower and not a terror bomber.

[NezA]

I followed the VPD chart all the way to harvest and this Disco Biscuit has some pretty solid buds absolutely no rot whatsoever. But this is my first run following the chart perhaps I was lucky. We'll see if it was a fluke or not as time goes on. I'm planning to continue following the charts from here on out so time will tell.

 

I've never had rot before so if I get even 1 instance that'll be a deal breaker for me and I'll switch to the method suggested by @zen-ken but so far so good.

 

I think it's the balance of humidity and temp that's the key as to why a lot of people don't encounter rot when following VPD. If you had say 60% humidity and 22c temps then there's not enough pressure on the plant to transpire causing the air around the plant to become stagnant. My theory is if stomata are kept constantly open and constantly exchanging gases then the air can't stagnate and the microclimate around leaves and buds is constantly changing through the plants own metabolic processes. Just a hunch based on my own experience and the learning that I've done over the last year or so.