Btw yes I’m odd. I also think you have the right approach once it is established, kill it without mercy. Once established all this environmental stuff just keeps it where it is. It won’t reverse the infestation
New views on PM and RH.....
- Thread starter Dr. Who
- Start date
Dr. Who
Well-Known Member
Winter dude, winter......How are they open in cold months? You have no idea just how a real greenhouse operation runs..... Your simply looking at one and guessing......Your wrong too.
Your stuck on one thing......You must run a sealed environment to gas. You control environment better sealed.
It does not take turn over to keep a room from growing PM...
YOU choose that.....good for you!
Many of us choose something else to focus on.
Now how about you get off your soapbox and stop preaching 1 opinion.....Your "barking" up the wrong tree.... Go troll another post..
I don't "ignore" air movement....I run fans...
I am now, Ignoring you....
Um yes I am 100% again adding co2 from natural gas. Not only is it vad For the inviroment it creates ton of problem. Also my previous two room circulation does work with CO2. Basically you are saying you can either seal the grow room or seal nothing. That is a silly simplification. You can seal around the grow room.
Again you can claim you grow the best shit but clearly it not perfect and you fail to understand the difference between greenhouses and an indoor Growing inveroment. Sorry i tickled you ego. Try learning thermodynamic and some basic environmental science before saying your the biggest baddest grower
Diabolical666
Well-Known Member
He didnt make those claims tho..you did just now. Dr. just named his past and present experience.
OldMedUser
Well-Known Member
Interesting stuff about a higher rh preventing PM via this cuticle layer.
I've never had PM problems and my rh is chronically low. Last year I got some plants off a buddy that had PM on the lower leaves so I removed the worst of them and sprayed the plants down with dilute potassium silicate, (Rhino Skin), and never saw PM again. I had other plants in there that I grew that never got it either tho I know there must have been an abundance of spoors floating around in there. This was in the spare bedroom that has nothing but a screened window for ventilation. No exhaust fan and just a small oscillating tower fan to flutter the leaves and move the air around a bit. Room is 10x10'.
Wish I could say the same for the mites also on those 'gifted' plants but I'm pretty sure they are finally gone.
I've never had PM problems and my rh is chronically low. Last year I got some plants off a buddy that had PM on the lower leaves so I removed the worst of them and sprayed the plants down with dilute potassium silicate, (Rhino Skin), and never saw PM again. I had other plants in there that I grew that never got it either tho I know there must have been an abundance of spoors floating around in there. This was in the spare bedroom that has nothing but a screened window for ventilation. No exhaust fan and just a small oscillating tower fan to flutter the leaves and move the air around a bit. Room is 10x10'.
Wish I could say the same for the mites also on those 'gifted' plants but I'm pretty sure they are finally gone.
Dr. Who
Well-Known Member
Your post's tell us who/what you are...
Thermodynamic's? This alone says who you are!
Thermodynamic's has nothing to do with Air movement in relationship to anything being discussed here...
Thermodynamic's is physic's. Dealing with heat/temperature and their relation to energy, work and radiation. Chemistry and Engineering have sections in it...
Continuous air exchange and gassing works? Nuff said there pal.....
Go troll another site.
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vitalsine
Well-Known Member
@Dr. Who Any updates on this?
I have just been focusing on RH and temp and didn't know much about VPD. Now that I have an understanding of the formula, I am trying to dial it in.
With that said, is having an ideal VPD more important than anything else? Say I keep my humidity at 60% and temp at 84F, and my leaf temp is 80F, I would have a VPD of 1.11, which is in the ideal range for veg. That's where I am currently sitting. I will obviously make adjustments to get my VPD dialed in for flower when I flip, but I am wondering if the high RH is necessary to achieve the level of VPD you desire. I read that flower prefers 1.0-1.5. By my calculations, if you have a temp of 77F, 50% RH, and 74F leaf temp, you'd have a VPD of 1.28, which sounds pretty ideal. I guess the idea is to find the optimal VPD without going to high/low in temp or RH... light distance would also have a big effect on the leaf temp as well as airflow. If I'm getting this all wrong can someone chime in, or am I on the right track?
I have just been focusing on RH and temp and didn't know much about VPD. Now that I have an understanding of the formula, I am trying to dial it in.
With that said, is having an ideal VPD more important than anything else? Say I keep my humidity at 60% and temp at 84F, and my leaf temp is 80F, I would have a VPD of 1.11, which is in the ideal range for veg. That's where I am currently sitting. I will obviously make adjustments to get my VPD dialed in for flower when I flip, but I am wondering if the high RH is necessary to achieve the level of VPD you desire. I read that flower prefers 1.0-1.5. By my calculations, if you have a temp of 77F, 50% RH, and 74F leaf temp, you'd have a VPD of 1.28, which sounds pretty ideal. I guess the idea is to find the optimal VPD without going to high/low in temp or RH... light distance would also have a big effect on the leaf temp as well as airflow. If I'm getting this all wrong can someone chime in, or am I on the right track?
Tetrahedral
Well-Known Member
It's 33c and 19percent humidity in Afghanistan today, that should tell you a lot about VPD.
Kushash
Well-Known Member
It doesn't sound good. In his last post in the thread below he said he was going to update the next day and never returned after posting in late May. I brought it up once in the covid thread in TNT and was wondering if anyone had a contact email. It was odd because he was in the middle of documenting his 1st LED grow. Someone with his contact info needs to check on him.
Doc's World ending swap to LED - SIDE by SIDE
Well, I didn't do much for an unpacking selection of photo's (boring). Same for setting them up (boring) BUT, I will say they Have real good packaging, as they did get bumped around. So they came out with 0 (zero) damage! Hung easy peasy. Here is the HLG board Here's the custom built board...
www.rollitup.org
OldMedUser
Well-Known Member
Sounds like you're on the right track. I only got clued into VPD a couple years ago and it cleared up a real puzzle for me. For years I was getting toxic salts buildup that showed up in mid flower and could fry leaves rught up into the tiny bud leaves by the time the plants were done. I thought it was too much N or just nutes too high and experimented with all sorts of ppm levels etc.
I finally realized it was because of our chronically low RH here in northern Alberta and that caused the plants to drink so much more water than they should thus drawing up extra nutes that get stored in the leaves eventually causing them to burn from the inside out. What I started doing was using much lower ppm in DWC and going down to about 1/4 strength nutes in my potted plants and that helped a lot. Still easy to get a burn going but now that I know what's going on I'm getting much better results. Our RH has been higher than normal this summer as it's been a lot wetter than usual but all my indoor plants are vegging and liking it fine.
I find that if I get the RH up to where those charts tell me to it's too moist and my cool cement floor and walls in the basement grow room get 'sweaty' so I have to be around 10% lower than that.
OldMedUser
Well-Known Member
Dr. Who
Well-Known Member
I'm back..... It was a sabbatical.
Tired and frustrated with covid shit.
Spent the time focusing on the parts of the farm. The organic Hops and barley/wheat operations have gone through the roof.
Spent some time kayaking out west too.
Got a Road king project finished (117ci sleeper engine.... you would never know it's a stroked 110..marked as a 103) and been riding a lot also.
So I'm back for a bit.
ISK
Well-Known Member
good to hear all is well, as I was concerned that you may have had medical issues
Dr. Who
Well-Known Member
Considering that I measure room temps by levels and over years of runs. I like to hold about a 72F ambient. I get higher 70's at the canopy and pot level, around 68-70F.
Room pressure is effected by Pos or Neg air pressure from how you use/move the air.
Just started to use a minisplit in one of the rooms I run. This has made me run an exhaust for 5 min on the top of the hr, during lights on. This is to draw in fresh O2, as depletion is now a factor. I quickly found that in the ripening stage. It's better to slow that turn over down some (helps keep the ethylene gas [ripening agent] able to do it's job). I now get an on time/stable and predictable finish. It also made me do more in the way of keeping "like" running strains in that room for better consistency in the perpetual harvest rotations I run.
As for keeping the RH up to help check PM?
It didn't work as well as it was supposed to. I get the feeling the piece was written by book learn'en and not so much from real experience. Odd too, cause the guy that wrote it - IS a commercial grower....
Flowki
Well-Known Member
Tbf I was also starting to wonder where you had got too. Like good old uncle Buck I figured you'd had enough of RIU
I have some questions for you or anybody that can answer. Maybe it will help others too.
As far as I am aware cob/led need to run higher temps and also higher humidity.
In the past I ran inkbird thermal cut off>volt stepped lowest flow out-take at 75f (77peak) and 50%RH (55 peak). This lower range of temps just made sense for climate energy costs +fear of high rh. I have always had small outbreaks of mold if RH gets too high with bigger buds. On the flip side if things get a little too dry this seems to give small outbreaks of botrytis. I ''think'' this is related to a few leaves suffering to over respiration/wind drying out the leaf stem in the bud and then being an easy target for bot. I deliberatly run lower RH and reduced PPM to account for higher respiration, it was an effort to keep mold down (perhaps a misplaced one). I normally expect 1-2% total loss to mold or bot but also have runs with no issues, seems to depend on time of year or particular bud size. However this was always acceptable loss to me since why change anything and risk a catastrophic 50%+ loss kinda deal. I didn't add any additional canopy air flow because of my above resp/wind dry bot ''theory'' for example, but no doubt it will be needed to run higher RH. The reason I mentioned that idea about bot is becuase when I read you taling about the pretective wax layer it made a lot of sense in that way. Doesn't mean I am right ofc.. but it's one more reason for me to stop being a pussy and try to run higher rh.
Recently I began paying a lot more attention to vpd and decided to give it a real shot, since I know the above isn't optimal. My biggest fear keeping me from following vpd has and always will be mold, pm so far has never been an issue (although it may be now with potential high rh swings). Everything I read up til that point was mold hazards of RH being too high. Now I am reading things like maintaining a steady RH will not give mold (with good airflow ofc) and ward off pm, should that become an issue.
The cycle I have now is temp set to 78-80 peak. Rh set to 65-70 peak (although extraction brings it down to low 60's, not sure if that's ok). Extraction is off for around 10 min as lights raise ambiant, then kicks in for about 2 to 3 min bringing temp to 78, the umidity climbs quite quickly once outake shuts off. In the winter this will be more like extraction off for 30 min, extraction on for 1 min. I am ok with these extraction off cycles letting the lights raise temps rather than blasting another 2k of heating, all I care about is no mold. I'm just explaining the set-up so people can comment on the RH swings or levels.
From what I've read recently here on RIU (correct my conclusions) lights off temp should sit at around 70f minimum. I will also change light timers so the light units individually switch off in 10 min intervals in order to stop a massive heat drop>due point. This should give heater time to level ambient out before total darkness. Keeping RH at 65% over night is what I need to be doing? how much of a swing is too much?.
I also don't use a mold filter for my in-take, this is probably something mandatory to get sorted too?.
On the pluss side I can absolutely confirm what others have said about keeping in the upper vpd range. For the first few weeks flower I let it run 80f 75rh and have never seen anything like it for pre flower growth, caught me completely off gaurd.
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OldMedUser
Well-Known Member
In these days of Covid and just us older farts dropping off the radar it's good to hear back from the 'thought you were dead' dudes like you @Dr. Who.
I'm hitting 66 next month and unless the mad dogs surrounding me get thru I expect to be close to 67 a year from now.
Keep on keeping on my dude but drop a dime once in a while so your family doesn't worry so much!
We really do worry ya know.
Dr. Who
Well-Known Member
Having switched over 1 building to (GOOD) LED's.
#1: I find no difference in basic ambient temps run - Between HD and LED.
#2: As far as lighting and penetration? I find some difference. I have adjusted by running well topped plants that are at least 1 ft shorter then I ran for HID. Some a tad shorter at about 18" less.
#3: For reference; I have NOT found any sativa growth issues vs HID in the LED's - In fact. The looser, more "pine tree" style of sativa growth. Gives me great results with LED! Almost better. I strongly suspect the vastly better light banding of the LED's
I DO USE mold filters for ALL incoming air!
Dr. Who
Well-Known Member
AwIn these days of Covid and just us older farts dropping off the radar it's good to hear back from the 'thought you were dead' dudes like you @Dr. Who.
I'm hitting 66 next month and unless the mad dogs surrounding me get thru I expect to be close to 67 a year from now.
Keep on keeping on my dude but drop a dime once in a while so your family doesn't worry so much!
We really do worry ya know.
Big hug out to Curious2garden also!
Flowki
Well-Known Member
I agree with the requirement to top a lot and flatten canopy for cob/led, the yield will suffer otherwise. I'm assuming HD is HID?, if so I've read that at-least 75F for led is required to keep leaf temps up in a usable range, while pushing 80+ is more ideal. Perhaps I have gotten confused with VPD rates that apply to sealed co2 growing?.
It was certainly far easier logistically for me to maintain 73-75f temps so I have no complaints going back to that, the explosive growth I seen from 80F-75RH was insane though, and accounts for something. Perhaps it is simply the case of higher RH, so 75F 65rh would give similar explosive growth, rather than my old 75f-55RH. I mean it was still good growth, but nothing like I seen with 80f-75rh.