Mold(s), root and bud rot

[justgrowing]

Lots of back and forth over VPD, ideal temps and humidity, not very indicative of cannabis cultivation threads 😉

Of those here who have grown, and/or who grow indoors with a 100% hydroponic setup, who can comment on having to battle with mold, root and/or bud rot?

I'm a new grower, 4x4 with a SF 7000, AC Infinity fan/controller, and have been utilizing an AC, dehumidifier, heater, and humidifier. I've invested a lot, I'm obsessive, I can be a Nervous Nelly, and I'm spooked about running into something that could jeopardize the fruits or my labor.

Any comments or feels about uglies you've seen, maybe what you've attributed them to, and how you've remedied any issues.

With the light on I've been trying to hit a VPD of around 1.5 +/- 2 with temp at 80° +/-2°, and a humidity level around 50% +/- up to 5%.

I'll post photos of my setup before long as I feel it's somewhat unique, would love some feedback on it.

Thanks ✌

 

[justgrowing]

I should have mentioned that with the light off the swing in my temp/humidity numbers is around 10 at most.

 

[freezeland2]

I’m going to assume you are very late in flower with a target vpd of 1.5 kPa +/- .2 is flirting with being in the danger zone of over transpiration. Personally, I try to maintain 1.4 kPa in late flower. I also drop my temps and rh is in the mid 40’s. No higher than 50% ever for me late flower.

 

[justgrowing]

I’m going to assume you are very late in flower with a target vpd of 1.5 kPa +/- .2 is flirting with being in the danger zone of over transpiration. Personally, I try to maintain 1.4 kPa in late flower. I also drop my temps and rh is in the mid 40’s. No higher than 50% ever for me late flower.

Unfortunately (maybe) my management of VPD hasn't been the greatest. I should have done some more research before I jumped into this, but I was leaning on a buddy who throws some caution to the wind (imo) and didn't introduced me to VPD until I was into my grow. I'm actually only on week three of flower, and am trying to dial back my VPD, but am still questioning VPD a bit as I've seen and heard a lot on both sides of really wanting to hit the sweet spot with precision.

~ n00b

 

[PipeCarver]

I’m going to assume you are very late in flower with a target vpd of 1.5 kPa +/- .2 is flirting with being in the danger zone of over transpiration. Personally, I try to maintain 1.4 kPa in late flower. I also drop my temps and rh is in the mid 40’s. No higher than 50% ever for me late flower.

..." No higher than 50% ever for me late flower. ".....I wish....never can I get my rh that low except a few weeks in the dead of winter when its -20c outside......I'm at 55% @ 78f now with dehue running full time......as long as I don't get it up over 60% I'm happy. I'll put on another dehue if it gets into the 60's and with good air movement I haven't had mold issues.....without air moving I grew grey mold the size of small mice wrapped around my stalks.....3 oscillating fans running 24 7 now..

 

[beluga]

The more you can stabilize, the less you'll be susceptible to fungi and disease.
Fungi thrive in pockets of microclimates. In damp roots with little oxygen.
The free transfer of air is going to be one of your main defenses against many many afflictions.

Had I been able to prevent microclimate pockets and keep my temperature and humidity more stable, I wouldn't have caught PM my last grow.
Well, to be exact, PM wouldn't have had the opportunity to germinate and thrive on my last grow. Its spores are everywhere; it's just a matter of it finding a hospitable environment to grow on.

 

[justgrowing]

Trying to at least maintain this right now. Flower week 3 photos here, getting a little crowded, two indicas, two indica/sativa.

🤞

 

[freezeland2]

Trying to at least maintain this right now. Flower week 3 photos here, getting a little crowded, two indicas, two indica/sativa.

🤞

View attachment 1286078 View attachment 1286077
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What is the leaf temp offset?

 

[justgrowing]

What is the leaf temp offset?

I can't say that I've measured that.

 

[growsince79]

I just looked at 3 different vpd charts and the numbers were all different. I have 3 different ir guns and get 3 different leaf temps. Shit is way too complicated for my tiny brain to figure out.

 

[CookiesLikeWhoa]

Much like @PipeCarver my summer grows have had a hard time getting below 50% RH and are usually sitting between 50-55% and sometimes as high as 60% during late flower.

I just chopped the grow that was going on in that tent, and neither had PM or Bud Rot. I do have 1 oscillating fan on the ground, 3 stationary fans above the canopy to keep the air flowing as well as an exhaust fan that's pulling out hot/humid air at the top.

Also keeping the ladies trimmed enough to allow that air to move around is key IMO. That allows that moving air to get where it needs to be.

 

[freezeland2]

I just looked at 3 different vpd charts and the numbers were all different. I have 3 different ir guns and get 3 different leaf temps. Shit is way too complicated for my tiny brain to figure out.

I let my controllers figure it out for me. I just set and maintain the parameters.

 

[freezeland2]

I can't say that I've measured that.

If you are under LED lights it’s probably around 4 degrees. You should enter that into your controller settings and watch what that vpd number does.

 

[justgrowing]

If you are under LED lights it’s probably around 4 degrees. You should enter that into your controller settings and watch what that vpd number does.

Noted

 

[PipeCarver]

Much like @PipeCarver my summer grows have had a hard time getting below 50% RH and are usually sitting between 50-55% and sometimes as high as 60% during late flower.

I just chopped the grow that was going on in that tent, and neither had PM or Bud Rot. I do have 1 oscillating fan on the ground, 3 stationary fans above the canopy to keep the air flowing as well as an exhaust fan that's pulling out hot/humid air at the top.

Also keeping the ladies trimmed enough to allow that air to move around is key IMO. That allows that moving air to get where it needs to be.

I also have fresh filtered cool input air from an un heated oil tank room at about 64f......Off note I used to work in a ship yard as an electrician.with the temp power & ventilation crew. Large ship holds we'd ventilate by putting a large input fan and on the other side the same sized exhaust fan....15 - 20ft deep same across large ship ballast tanks where welders are down inside working on the bulkheads. ..........We'd enter through hatches where the wind would be exhausting and blowing our hard hats off but once we we're in side, a few feet down the ladders it was calm...no wind and no smoke the smoke went out where the fans sucked it too....all was at peace except for the arcing from the welders.......

Long story short I want the same thing....just a nice steady flow of fresh air through the tent along with my fans to disrupt the flow and move my girls. leaves around..... too hot I increase the air flow...too cold I slow it down & or this year I have reptile heat lamps I can add and slow down or change input air locations.