This is low humidity damage, right?

Gobi

Gobi

Well-Known Member
My ladies have started showing some problems. I'm almost sure it's due to low rh. Can you guys confirm?

With the lights on the temp in the tent is 77-80. The rh has been around 35%. General guides seem to say 40% is ok so I added a humidifier, placed it poorly and didn't run it high enough. That got the tent to around 40%. I now know what a VPD chart is and realize my rh is way too low. Running two small humidifiers at full blast is now keeping the rh between 55% and 60%. I also adjusted the light schedule so it's dark from Noon to 6. Will that clear up the issues?

20201011_112728.jpg

This one has some yellowing on the leaves. These patches felt very dry before they turned yellow.

20201011_112832.jpg

This problem appears on one of the other plants. One of them is also showing slightly burned tips. I haven't added any food, so I think it's just pulling too much from the soil due to the low rh.

Growing in soil under a TS3000.
 
Gobi

Gobi

Well-Known Member
Merlin1147 said:
Looks like Mg deficiency to me.
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Is that because of the leaf stems? Another user in the Useful Seeds thread says that happens with this strain. One guy isn't proof, though. I'll add a little Epsom salt to the next watering.
 
pulpoinspace

pulpoinspace

Well-Known Member
they look fine. 35% RH should be fine it gets down to that or lower here and i dont see problems on the veg plants.

red petioles can be genetic or mg deficiency or lockout from too low pH, which would be my hunch here.

but overall they look fine just youngins
 
Scuzzman

Scuzzman

Well-Known Member
have had the same issue using megacrop in recycled coco coir, the best fix I found and the fastest is mix 1 liter of ph water 6.2-6.4 and 3 grams of epsom salts and spray every day 2-4 times - light mist on top and under the leaves, takes approx 1 week to sort- you can also add alittle cal/mag as well if needed - this works well in my garden,have 1 room at 35% Humidity( this helps fix problems in my view) and 3 others at 55% and 27 degrees stable
 
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Xs121

Xs121

Well-Known Member
Gobi said:
So are VPD charts bullshit?
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The VPD chart is there for a reason and scientific at that....it not only tells you the ideal humidity and temperature for the plants....but it tells you the best combination of humidity and temperature for the plants to function "optimally".

Sure plants can survive in low humidity
Sure plants can survive in high humidity
Sure plants can survive in low temperature
Sure plants can survive in high temperature

But is it optimal?

I find that with cannabis, the plants, require less feeding and least stress at VPD around .7-.9

I dont know Joeblow growing conditions but I cant help it to notice he doesnt mention at what temperature is his healthy plants at 20% rh. But I really doubt cannabis would be healthy at a temp of the 80+F and 20%rh.
 
JoeBlow5823

JoeBlow5823

Well-Known Member
Xs121 said:
The VPD chart is there for a reason and scientific at that....it not only tells you the ideal humidity and temperature for the plants....but it tells you the best combination of humidity and temperature for the plants to function "optimally".

Sure plants can survive in low humidity
Sure plants can survive in high humidity
Sure plants can survive in low temperature
Sure plants can survive in high temperature

But is it optimal?

I find that with cannabis, the plants, require less feeding and least stress at VPD around .7-.9

I dont know Joeblow growing conditions but I cant help it to notice he doesnt mention at what temperature is his healthy plants at 20% rh. But I really doubt cannabis would be healthy at a temp of the 80+F and 20%rh.
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Oh i keep temps at 80 in the veg area which is usually anywhere from 20-30%. For flower i keep under 78. HPS. Ideally 75. They like it cool. Just saying, ive had very healthy girls at 20% so if he is at 35, should be no worries unless something else is drastically wrong.
 
JimmiP

JimmiP

Well-Known Member
Gobi said:
Overcomplicating things is the story of my life. I'm taking your advice. I just watered them today, so it will probably be 6 days before they're thirsty again. I'll try the spray. First time for everything
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Are you using a cool or warm mist type of humidifier? I would use the warm mist type and if you can, slow down your air exchange. I believe you were on the right track in your first post about over transpiration. Also are you growing with hid or led? If its led I would increase the temperature too.
Also I see a lot of white specks on some of those leaves. Have you checked them for mites?
Good luck friend!
 
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Gobi

Gobi

Well-Known Member
JimmiP said:
Are you using a cool or warm mist type of humidifier? I would use the warm mist type and if you can slow down your air exchange. I believe you were on the right track in your first post about over transpiration. Also are you growing with hid or led? If its led I would increase the temperature too.
Also I see a lot of white specks on some of those leaves. Have you checked them for mites?
Good luck friend!
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Cool mist. I am using led. The temp right now with the light on is 77. It . That's with two walmart, bedroom-type humidifiers running on high. I do have the exhaust fan set at 70% (temp was staying at 80 until the last day or two). Lowering that should make it warmer. How warm should it be?

I took a good look at the plants after you mentioned mites. I'm 99% sure those spots are from me turning on a dusty shop-vac near the open tent today. Dumb, but I can't see any other evidence of mites.
 
TintEastwood

TintEastwood

Well-Known Member
Visually bloated from overwatering.
I see lots of small white specs of leaves, be sure to keep an eye out for pests.

Leaf issues look like PH to me.
For example...Too low and less effective uptake of Ca Mg Phos.

soil-ph-chart-marijuana.jpg
 
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Bukvičák

Bukvičák

Well-Known Member
Now they are over watered as guys said above thats why they are droppy, but the damage is from underwatering...
 
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