October 18, 2023 at 2:44 pm #2982
Is this trying to tell me anything important?October 20, 2023 at 2:30 pm #2999
Gonna stack two more questions with the above..
I’m not concerned or anything, just hoping to learn how to read the “symptoms,” understanding that some will be nothing and some will actually be a call to action.
I read deeper into VPD and did not realize that the leaf temperature was the thing to go by as opposed to the ambient air. Makes perfect sense. I am going to order a infra red gun to see what my lst is. I wen ahead and adjusted the offset up by 3 degrees in the ACInfinity app. This being an HID grow, I understand now that lst will be higher due to wasted radiant energy from the light source. So my VPD with lights on is somewhere on the order 1.6-1.9 I think. Will confirm when I get the temp gun. I’m not panicking or anything, but if I can dial that in more, all the better.
I can’t bring temps down. They’re around 75-77 degrees in the tent at all times. With lights off the VPD becomes ideal. So my only option during lights on is to add humidity. I’m not going to do that in the lung room until it gets colder here in the winter. At that point I wouldn’t mind supplementing the lung room if need be because the central heat lowers humidity beyond our living comfort zone anyhow. But for now it would have to be a humidifier in the tent. If I get one, it would have to be placed dead center on the floor, and it would also have to be small. I’m looking at a 4L smart Levoit in potential.
A couple things holding me back. One, it will be kicking out its mist straight up and centered in the room, so pointed straight at the glass of my air cooled hood. I have an oscillating fan on at all times, so I don’t know if that would negate condensation buildup on the glass? If so, check.
Possible issue number two, depending obviously on the heat from the HID light, I have to extract pretty heavily most of the time to keep the temps where I need them. So I’m thinking the added humidity from the 4L humidifier might just get constantly sucked out and do practically nothing? If I turn the exhaust down, temps go up and then I’d be left chasing after higher humidity than I want or could even maintain.
So it boils down to knowing wether or not a small humidifier can bring humidity up by at least 5% with high extraction. If not, the variables will never line up. And if that’s the case, so be it. Dialing in VPD will be easier in flower which I’m assuming is ultimately more important than during veg. Thoughts?
Lastly, my first true leaves are starting the process of dying. No biggies, just curious if this is a total normal and healthy looking pattern of die off? Thank you!!!October 20, 2023 at 2:31 pm #3000October 21, 2023 at 3:32 pm #3004mrgrowitKeymaster
I highly recommend the AC Infinity humidifier (discount code: MRGROWIT15) over the Levoit smart humidifier. Not only is the AC Infinity humidifier priced lower, but it is able to dial in RH way better than the Levoit one can. I actually stopped using the Levoit humidifier.
Which inline fan are you using right now? Does it have a variable speed controller? Also, is it on a timer? Hard to tell you for sure if the humidifier will sufficiently increase the RH if you’re constantly exhausting air from the grow space.
That damage on the lower leaf resembles beginning symptoms of over-watering imo. Basically it’s a lack of oxygen in the root zone and the leaves on the lower part of the plant suffer first. Again, are you tell you for sure that’s what it is, but it sure resembles it. Letting the soil dry out a bit more between waterings should eliminate that from getting worse.
In regards to what you mention about easier to control RH in flower, it can be. The bigger the plant the more water vaper will enter into the air via respiration.October 21, 2023 at 5:24 pm #3009
I’ve got an AC infinity in-line and exhaust, as well as two of their 6” oscillating fans, though currently only using one. Thanks for the heads up about the T3. That was the other one I was looking at. I’m also consider the ACI bigger humidifier, as I will need it for my lung room when I eventually get to the drying phase. I could place it outside the tent and use the tube to humidify inside the tent. There seems to be conflicting opinions about how well this works based on the bend in the tube and the water that collects inside of it. I imagine I could make it work for me somehow.
I think you are probably right about the overwatering. Thanks for enlightening me about that. I had accidentally watered 12-24 hours early. I was looking at the calendar after midnight and thoughtlessly got confused because the date had changed, but it was still about one night too early. Lesson learned. I’ll make sure to factor that in when I’m looking at my calendar.
My produce farm has a lot of fungal disease pressure due to too many hours at sub-optimal VPD. My climate is the total opposite of your! I had read a study that showed a correlation between higher brix and low VPD stress. How does brix in cannabis relate to terpenes and bud quality? I was thinking that in terms of various controlled stresses, if there were a positive correlation between terps and brix then if that study were accurate (only one study I saw about it..) then perhaps inducing a bit of low vpd stress in flower would be superior to high vpd stress. Of course mold has to be considered, but perhaps bursts of low vpd stress through until the mid-phase of flower could be beneficial?October 25, 2023 at 3:23 am #3016
Not loving the looks of this. It’s on the same plant that had the fugly first true leaf. This is on the second set. I’m assuming that means it’s not a calcium deficiency. Hoping it’s not septoria leaf spot. Here’s an updated picture of that original first leaf. I went ahead and removed the first leaves on this and another plant, and sliced off the portion of the second leaf with these small dark spots, using alcohol in between each cut. Maybe it’s something else? I have a hepa filter on my intake fan. But, there is septoria leaf spot on my greenhouse tomatoes, as well as in the leaves of plenty of pioneer native annuals outside. Gonna start researching how to stop it from spreading if that’s what it is..October 25, 2023 at 3:24 am #3017October 25, 2023 at 3:24 am #3018October 25, 2023 at 3:25 am #3019October 25, 2023 at 2:12 pm #3020
After looking at it under 50x (wish I had more powerful..), I’d say IF it’s a fungal disease, I’ve certainly caught it early enough to possibly nip it in the bud with a combination of copper, neem with baking soda and maybe another spray round of potassium bicarbonate. Also not totally ruling out the potential for it being a result of a too soon watering mistake.
I’ll go ahead and address the other two potential concerns, which appear to be unrelated to those dark spots. One is some beige spots, not too widespread. The other is the two color tones on a fair number of leaves. I suspect it’s either A) the beginnings of magnesium deficiency or B) symptoms of light to moderate overfeeding from using nutes twice now, which I’m going to pause on. Water is pH 22.214.171.124 or so, with lowest dose of calmag. One of the parents of these plants is Cinderella 99. Everyone including the breeder mentions that it is especially hungry for calmag, so maybe I need to bump it up, but I don’t want to rush to conclusions 😉
Thank you for your support!!October 25, 2023 at 2:12 pm #3021October 25, 2023 at 2:19 pm #3022
Just subscribed so I can start paying you for your help here ;))October 25, 2023 at 4:42 pm #3027mrgrowitKeymaster
Thanks for the support on Patreon! Which AC Infinity controller do you have? I ask because some of them allow you to set by VPD, so your fan could kick on according to that instead. Or, if humidity is too high, or temp too high. Lots of flexibility with that controller. Also the humidifier will connect to the newer controller; not sure if the older one can.
I’ve heard of the tube on the humidifier causing issues too. I personally don’t use it.
Your question: “How does brix in cannabis relate to terpenes and bud quality? … perhaps bursts of low vpd stress through until the mid-phase of flower could be beneficial?”
Answer: I’m not aware of any studies to back up that. All I hear is anecdotal evidence.
Are these the same plants being transplanted into 7-gallon grow pots soon or are those different plants? If they are being transplanted soon, the larger grow pot with fresh nutrients may be all it needs to bounce back.October 25, 2023 at 4:54 pm #3028
Yep, these are going into 7 gallons tomorrow. I wanted to do it sooner but they took awhile to show up. My disease fear is just simply that I’ve struggled a lot this year on the farm with disease. I’m always on high alert and worry about accidentally bringing pathogens into the tent. I suppose I’ll try to be patient and see how these spots play out after transplanting. Hopefully they’re just simple growing pain blemishes!October 25, 2023 at 4:55 pm #3029
<p style=”text-align: left;”>I have the 69 pro</p>
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