VPD... yes, another thread on it, but with a twist.

[DoubleAtotheRON]

Looking for some real experience here. I've ran a crop following VPD to the T during veg and early flower, and have failed for microbes before (mold/bud rot) without an H203 system. Last run was with an AirROS H203 system and labs came back with "non detected", but I cut back my RH during the last 5 weeks. State threshold is 10,000 colonized fungal units.
Starting week 5 tomorrow, and my setup is ...
Lights on: Starting temp ~72, ending temp ~84 RH: Starting ~56 ending ~74
Lights off: Starting temp ~84, ending temp ~72 RH Starting ~74 ending ~ 56
Running CO2 in a sealed 20x30 room at 1400ppm (propane generator during lights on) and an AirROS H203 generator 24/7.
My question is, does anybody have any experience following the VPD chart all the way to the finish without mold AND running some sort of H203 system?
I want to trust the H203 is going to do it's job, but a failed set of labs would be devastating.

 

[newbplantgrower420]

i had dehumidification issues last run. daytime was okay but my RH would spike to 75% at nights for the last 2 weeks.... i still didnt get mold... just some bud rot on my fattest nugs. had 2 strains in there.

as long as the air doesnt stay stagnant and is constantly moving... i dont see why u should get mold.

most of what ive read from other forums is ppl running VPD until the last week or two then dropping temps and humidity gradually primarily to avoid bud rot. i keep it the same throughout... ~80F/60% ideally.

 

[DoubleAtotheRON]

i had dehumidification issues last run. daytime was okay but my RH would spike to 75% at nights for the last 2 weeks.... i still didnt get mold... just some bud rot on my fattest nugs. had 2 strains in there.

as long as the air doesnt stay stagnant and is constantly moving... i dont see why u should get mold.

most of what ive read from other forums is ppl running VPD until the last week or two then dropping temps and humidity gradually primarily to avoid bud rot. i keep it the same throughout... ~80F/60% ideally.

Bud rot IS mold... we have to test our product. I was looking specifically for anyone who has run a H203 system while following VPD to the finish. I do drop my RH to ~56 at lights off with the AC set on DRY, and cranking up the dehumidifiers.

 

[newbplantgrower420]

ive ran ~80F/60% hum throughout an entire run and havent got any sort of mold. even spiking to 65% at nights with 75F temps and never had bud rot or pm before.

only reason i had anything last run was i changed my setup quite a bit and miscalculated how much dehumidification i needed.

ive even took care of a room that for 1 run would go down to 60F and 70% humidity at nights late in flower and still didnt get pm nor bud rot. it was 1 strain in there... it was an OG. the boss didnt want to drop some dough on another dehumidifer so we kinda just rolled the dice and luckily it worked out. nugs werent that big though so bud rot wasnt really a concern.

maybe if you have those certain strains that have very tight internode spacing and end up being 1 really long,fat nug at the end. id be concerned for bud rot. but then you can always have your circulating fan blowing at them slightly.

as far as humidity %... 72F and 56% should be fine.

 

[Mont@n@]

Looking for some real experience here. I've ran a crop following VPD to the T during veg and early flower, and have failed for microbes before (mold/bud rot) without an H203 system. Last run was with an AirROS H203 system and labs came back with "non detected", but I cut back my RH during the last 5 weeks. State threshold is 10,000 colonized fungal units.
Starting week 5 tomorrow, and my setup is ...
Lights on: Starting temp ~72, ending temp ~84 RH: Starting ~56 ending ~74
Lights off: Starting temp ~84, ending temp ~72 RH Starting ~74 ending ~ 56
Running CO2 in a sealed 20x30 room at 1400ppm (propane generator during lights on) and an AirROS H203 generator 24/7.
My question is, does anybody have any experience following the VPD chart all the way to the finish without mold AND running some sort of H203 system?
I want to trust the H203 is going to do it's job, but a failed set of labs would be devastating.

82f - 55%-75%rh.
Here is a copy paste from a old thread that I posted. Good luck

light for a veg box?

Hello guys i have a grow box for which is 60x60x160 cm. i placed 3x120 quantum boards in this box. Now I've bought myself a small box for veg which is 80x60x80 cm what light should I use there ideally? I'm gonna keep my autos there for 1 month and then transfer them into the 60x60x160 cm

www.rollitup.org

If you grow between your golden numbers of vapor pressure, you will see the difference and it will make you a better grower for you and your plants.

for example: my flower room (aero/nft) fluctuate between 60-70% RH. my safe zone temperature based on the chart is 80-82f.
Here are my numbers from the chart:
80.6f - 27c (mini split a/c, CO2 700ppm)

My safe zone RH% with air circulation

RH% VPD (kPa)
85% - 0.54 Fungal Pathogens
80% - 0.71 MAX (big chance of fungal)
75% - 0.89 x Safe Zone Max
70% - 1.07
65% - 1.25
60% - 1.43
55% - 1.61 x Safe Zone Min
50% - 1.78
45% - 1.96 MIN
40% - 2.14 High Stress Zone
(I use Growtronix to monitor this numbers)
Happy growing

 

[ttystikk]

Bud rot IS mold... we have to test our product. I was looking specifically for anyone who has run a H203 system while following VPD to the finish. I do drop my RH to ~56 at lights off with the AC set on DRY, and cranking up the dehumidifiers.

I've never run an ozone generator but as with most things of that nature, if you have to use someone line that, it's generally because there's something else in your grow that's causing problems.

In your case, I would look very carefully at the temperature swings you've reported between day and night. There is no demonstrated need for temperature to vary much when growing medicine. When temperature moves around, so does RH, and I don't care how big your dehuey unit is, that's just going to be a fact of life. As temps fall, RH will swing upwards, and it's that very change that encourages mold and mildew. The problem is perhaps worse when following VPD guidelines because you generally start with higher RH to begin with.

The best way to both follow VPD guidelines for optimal growth conditions (and I recommend it) and keep your operation mold and mildew free is to lock down the temperature do it doesn't change more than maybe 5 degrees F. If that means heaters at night, so be it.

Suggestions above about keeping good air circulation are also a great idea but they won't solve the problem alone.

 

[DoubleAtotheRON]

I've never run an ozone generator but as with most things of that nature, if you have to use someone line that, it's generally because there's something else in your grow that's causing problems.

In your case, I would look very carefully at the temperature swings you've reported between day and night. There is no demonstrated need for temperature to vary much when growing medicine. When temperature moves around, so does RH, and I don't care how big your dehuey unit is, that's just going to be a fact of life. As temps fall, RH will swing upwards, and it's that very change that encourages mold and mildew. The problem is perhaps worse when following VPD guidelines because you generally start with higher RH to begin with.

The best way to both follow VPD guidelines for optimal growth conditions (and I recommend it) and keep your operation mold and mildew free is to lock down the temperature do it doesn't change more than maybe 5 degrees F. If that means heaters at night, so be it.

Suggestions above about keeping good air circulation are also a great idea but they won't solve the problem alone.

I do have good air circulation 24/7. I have two, 24 inch industrial swing fans up high, a 10 inch HyperFan on the floor that blows the air under the tables, and a 3 ton AC unit on swing. Everything dances around nicely.
I have a Spartan controller than I can see the temps go from 83 ish to 74 ish during lights out, and RH 73 ish to low 60’s. So my RH is dropping throughout the night along with the temps. When you say something else had caused mold, perhaps. .. it was a summer run, and mold spores were bad. Mushrooms were growing everywhere outside. Maybe just bad timing, as we have not failed for microbes in the 2 years prior. But after we did fail labs, that’s when we invested in the AirROS, and have passed the last 2 rounds with “none detected”... but like I said, I had dropped off the VPD chart as a precaution.
Our grow is featured on AirROS’s website, and they assure me that the system will kill anything at any level of RH, but a failed room means I got 30 lbs of worthless weed. So, you can see my concern.
Following the chart dead center so far has proven to be explosive tho!

 

[DoubleAtotheRON]

82f - 55%-75%rh.
Here is a copy paste from a old thread that I posted. Good luck

light for a veg box?

Hello guys i have a grow box for which is 60x60x160 cm. i placed 3x120 quantum boards in this box. Now I've bought myself a small box for veg which is 80x60x80 cm what light should I use there ideally? I'm gonna keep my autos there for 1 month and then transfer them into the 60x60x160 cm

www.rollitup.org

If you grow between your golden numbers of vapor pressure, you will see the difference and it will make you a better grower for you and your plants.

for example: my flower room (aero/nft) fluctuate between 60-70% RH. my safe zone temperature based on the chart is 80-82f.
Here are my numbers from the chart:
80.6f - 27c (mini split a/c, CO2 700ppm)

My safe zone RH% with air circulation

RH% VPD (kPa)
85% - 0.54 Fungal Pathogens
80% - 0.71 MAX (big chance of fungal)
75% - 0.89 x Safe Zone Max
70% - 1.07
65% - 1.25
60% - 1.43
55% - 1.61 x Safe Zone Min
50% - 1.78
45% - 1.96 MIN
40% - 2.14 High Stress Zone
(I use Growtronix to monitor this numbers)View attachment 4879449
Happy growing

Thanks for the chart!.. I have one, but this one separates out the stages. So, according to this, im at a 1.40 max during the day, and about 1.32 max during the night. .... Good stuff man, gonna print this one out and replace my old chart.

 

[bk78]

Thanks for the chart!.. I have one, but this one separates out the stages. So, according to this, im at a 1.40 max during the day, and about 1.32 max during the night. .... Good stuff man, gonna print this one out and replace my old chart.

Lots of great info here my dude

VPD Charts in Fahrenheit and Celsius With Leaf Temperature

We made some easy-to-use VPD charts for both Celsius and Fahrenheit, for clone, veg, and flower stages. Hope you find them useful. For more information about VPD check out our VPD Guide. VPD Chart Maker and Calculator I WANT IT Table of Contents VPD Charts for Fahrenheit VPD Chart for Clones...

pulsegrow.com

 

[DoubleAtotheRON]

Lots of great info here my dude

VPD Charts in Fahrenheit and Celsius With Leaf Temperature

We made some easy-to-use VPD charts for both Celsius and Fahrenheit, for clone, veg, and flower stages. Hope you find them useful. For more information about VPD check out our VPD Guide. VPD Chart Maker and Calculator I WANT IT Table of Contents VPD Charts for Fahrenheit VPD Chart for Clones...

pulsegrow.com

Thanks bud!.. appreciate it!

 

[rkymtnman]

nice room! way above my level but i do have a ?: is everybody that enters the room sterilized? like booties and a tyvek suit kinda stuff? or does that ozone generator kill anything like that as well?

 

[DoubleAtotheRON]

nice room! way above my level but i do have a ?: is everybody that enters the room sterilized? like booties and a tyvek suit kinda stuff? or does that ozone generator kill anything like that as well?

We do wear clean clothes when we enter the room, hair nets (not me, im bald as a baby), and 95% of the time, Im the only one that enters, but yes, the AirROS instantly kills any mold spores, pathogens, bacteria, etc as the air makes contact with it. It's even been proven to kill Covid19 at 95% in 15 min, and 100% in 45 min. I got Covid back in Sept. and I would just get a yoga mat and go lay in the room for a while every day. The AirROS releases Trioxidane (h203) at 30ppb.. that's B as in billion, so you could imagine how sensitive the sensor is (and expensive to replace yearly), but losing a crop to mold makes it unmarketable. We took a real kick in the nuts on that bad run. Had to cheap sell it to processors at $150 a lb. That's the only time you can sell failed product. If you fail for heavy metals, or pesticides, you have to pay the State to come pick it up to destroy it. All plants are RFID chipped, so they know what we got, and what we don't. Packaging to Dispensaries have RFID chip labels so they can track where all your inventory goes..... fucking pain in the ass.

 

[rkymtnman]

yeah, a buck fiddy a pound can't happen more than once i would imagine!!!

i made a DIY uv-c bulb in some 4" duct and an old inline fan i had laying around. i would run that upstairs in the house after we'd go out shopping during the early part of the covid shit. not sure if it helped but the cool blue glow coming out of the duct was pretty neat. lol!

good luck: may the spores (not) be with you!!!

 

[DoubleAtotheRON]

yeah, a buck fiddy a pound can't happen more than once i would imagine!!!

i made a DIY uv-c bulb in some 4" duct and an old inline fan i had laying around. i would run that upstairs in the house after we'd go out shopping during the early part of the covid shit. not sure if it helped but the cool blue glow coming out of the duct was pretty neat. lol!

good luck: may the spores (not) be with you!!!

We have one in our bedroom like that called a Molekule. It has a dual stage PECO filter system with a UV light tube up the middle of the main filter... pretty cool technology, and it makes a nice little night light when I gotta take a wicked pisser in the middle of the night.

 

[Doug Dawson]

I do have good air circulation 24/7. I have two, 24 inch industrial swing fans up high, a 10 inch HyperFan on the floor that blows the air under the tables, and a 3 ton AC unit on swing. Everything dances around nicely.
I have a Spartan controller than I can see the temps go from 83 ish to 74 ish during lights out, and RH 73 ish to low 60’s. So my RH is dropping throughout the night along with the temps. When you say something else had caused mold, perhaps. .. it was a summer run, and mold spores were bad. Mushrooms were growing everywhere outside. Maybe just bad timing, as we have not failed for microbes in the 2 years prior. But after we did fail labs, that’s when we invested in the AirROS, and have passed the last 2 rounds with “none detected”... but like I said, I had dropped off the VPD chart as a precaution.
Our grow is featured on AirROS’s website, and they assure me that the system will kill anything at any level of RH, but a failed room means I got 30 lbs of worthless weed. So, you can see my concern.
Following the chart dead center so far has proven to be explosive tho!View attachment 4879601

Never get tired of seeing your setup brother. Way cool.

 

[ttystikk]

We do wear clean clothes when we enter the room, hair nets (not me, im bald as a baby), and 95% of the time, Im the only one that enters, but yes, the AirROS instantly kills any mold spores, pathogens, bacteria, etc as the air makes contact with it. It's even been proven to kill Covid19 at 95% in 15 min, and 100% in 45 min. I got Covid back in Sept. and I would just get a yoga mat and go lay in the room for a while every day. The AirROS releases Trioxidane (h203) at 30ppb.. that's B as in billion, so you could imagine how sensitive the sensor is (and expensive to replace yearly), but losing a crop to mold makes it unmarketable. We took a real kick in the nuts on that bad run. Had to cheap sell it to processors at $150 a lb. That's the only time you can sell failed product. If you fail for heavy metals, or pesticides, you have to pay the State to come pick it up to destroy it. All plants are RFID chipped, so they know what we got, and what we don't. Packaging to Dispensaries have RFID chip labels so they can track where all your inventory goes..... fucking pain in the ass.

Does that ozone generator also affect smell?

 

[DoubleAtotheRON]

Never get tired of seeing your setup brother. Way cool.

Thanks man!

 

[DoubleAtotheRON]

Does that ozone generator also affect smell?

Yes... it's undetectable. If you shut the machine off, you'll have the stank in a few min. When I come out of the grow after watering, my clothes smell like ozone. But that's what is does is attacks VOC's (volatile organic compounds).. and just about everything from paint, to plants, to lego's have some sort of VOC.

 

[thenasty1]

Had to cheap sell it to processors at $150 a lb

thats pretty fucked. i dont know how it goes in ok, but around here the decent processors usually do splits (or 60/40 or whatever). if a batch has to be remediated for mold or whatever else, it just cuts down on the total yield, which is split up at the end according to the agreed upon percentage. less loot for sure, but definitely ends up at more than 150 per input lb to the grower
what im getting at is you should look for a new processor, thats some shysty shit. especially considering the volume you guys produce

 

[DoubleAtotheRON]

thats pretty fucked. i dont know how it goes in ok, but around here the decent processors usually do splits (or 60/40 or whatever). if a batch has to be remediated for mold or whatever else, it just cuts down on the total yield, which is split up at the end according to the agreed upon percentage. less loot for sure, but definitely ends up at more than 150 per input lb to the grower
what im getting at is you should look for a new processor, thats some shysty shit. especially considering the volume you guys produce

Dude, we shopped it around forever.. that was about the time that Croptober came around , and the market was flooded like crazy with tons available. Yeah, it sucked for sure, but nobody wanted to touch it. We started will $800 and couldn’t get any takers till we started lowering it. We were in a pinch as well, we had another crop coming up and I needed to move it out and clean the shit out of everything in the packaging/cure room. Lesson learned. We’ve been fucked on splits before, and I wasn’t going to go through that again. ... there’s some shady processors in this biz, so we cut our losses and moved on.