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Reddish Brown Leaves and Sugar Leaves? Cold maybe

EastCoastGambit

Well-known member
I have noticed some reddish brown fan leaves on my plants and the early buds sugar leaves had the same thing going on. I was thinking it was due to cold nigh time temps but could it be something else (deficiency) of sorts.

I'll post a photo in a minute.
 

EastCoastGambit

Well-known member
20231108_111735.jpg
 

Creeperpark

Well-known member
Mentor
Veteran
The best way to tell the difference between phosphorous temperature decline and phosphorous deficiency is to do a pour-thur, catch a little runoff, and test it. If the ppm has dropped low then raising the EC will keep the nutrients up enough till the end of flowering.
 

Creeperpark

Well-known member
Mentor
Veteran
Using an EC or TDS meter is a must for maintaining the perfect EC. Without one a person can only guess and hope for the best.
 

EastCoastGambit

Well-known member
Thanks. I'll keep an eye on the EC. Im typically not that technical and try to run my nutes fairly lean, perhaps this is folly.
 

led05

Chasing The Present
The best way to tell the difference between phosphorous temperature decline and phosphorous deficiency is to do a pour-thur, catch a little runoff, and test it. If the ppm has dropped low then raising the EC will keep the nutrients up enough till the end of flowering.
It’s a P deficit for sure, K & N too, Ca I’d bet as well & couple micros

OP, what is your daily temp ranges, I didn’t see it posted? Can you take pic of underside leafs & Petioles too?

The purple is because of the cold. The yellow because of underfeeding. So both.
Yes I agree but also believe purpling due lack P as well…
 

led05

Chasing The Present
Yes. If you are yellow after flipping to flower is there any good way to address it?

I need to add more N in veg.
I’ve got a garage room that can swing 40F in a day and I believe plants love it, though more often once really cold it’s more like 25F swings on average which I believe is nearly ideal to get the best quality from them….

The biggest threat with cooler nights is overly wet soil imo
 

TanzanianMagic

Well-known member
Veteran

It's November.

Molybdenum gets locked out with cold temperatures.

At a more advanced stage:
1699557949219.png


"Cold temperatures. Cannabis roots function their best at temperatures between 15 and 30°C, with some growers/researchers claiming the sweet spot is somewhere around 24°C. Below 15°C, the rate at which cannabis plants take up nutrients and water via their roots drops significantly, and at 13°C, cannabis roots undergo a mild shock. Nutrient deficiencies can occur when the root zone is exposed to cold temperatures over extended periods as plants struggle to take up nutrients from their medium/fertiliser."
Source

I can't see most of the grow. However if the pots are on the ground, it is useful to put them on a folded crate or some planks.
 

EastCoastGambit

Well-known member
I would say the purpling is more due to cold because it only affected a few leaves and not the whole plant.

My temps were probably 74 F lights on and 63F lights off for a minute.

My temps controller scrapped out on me and my household heat wasn't on yet. I replaced the controller and am now stable at 82 F.
 

EastCoastGambit

Well-known member
Pots are on the ground. Definitely have cold wet feet. I'll put some insulting down. Almost looked like bud rot, the color that is, thought I know it isn't. It affected one strain SD x S. Bubble and not the other, chem 91 x S. Bubble.
 

led05

Chasing The Present
I would say the purpling is more due to cold because it only affected a few leaves and not the whole plant.

My temps were probably 74 F lights on and 63F lights off for a minute.

My temps controller scrapped out on me and my household heat wasn't on yet. I replaced the controller and am now stable at 82 F.
63F is fine for low IMO, nearly ideal in fact, get days into the mid 80’s, bright ass lights & you’re golden brother
 

led05

Chasing The Present
Pots are on the ground. Definitely have cold wet feet. I'll put some insulting down. Almost looked like bud rot, the color that is, thought I know it isn't. It affected one strain SD x S. Bubble and not the other, chem 91 x S. Bubble.
Yeah, that’s definitely a big issue, I like to have my tubs up on casters for ease of movement but definitely also that reason too ^^ GL buddy
 

Hammerhead

Disabled Farmer
ICMag Donor
Veteran
I agree, temp related. Cold causes all kinds of issues with Nutrient uptake. It also causes the medium to stay wet longer which causes the PH to drop. Plants need that wet/dry cycle in a soilless medium like Promix. ..

Be very careful with a space heater in a tent.. I would heat the room instead if possible.
 

EastCoastGambit

Well-known member
I agree, temp related. Cold causes all kinds of issues with Nutrient uptake. It also causes the medium to stay wet longer which causes the PH to drop. Plants need that wet/dry cycle in a soilless medium like Promix. ..

Be very careful with a space heater in a tent.. I would heat the room instead if possible.
I agree. I don't like it either. I try to do it safely via the thermostat in the heater and a secondary temp controller. Ideally I would have a room within a room thing where the heater would be outside the tent and I would be heating a small room. Keeping my basement at 75F isn't ideal. Maybe winter month grows are off the table for me for now. I have a family upstairs and am not looking to burn down my house. I have a nest smoke alarm right on top of my tent. I ran this setup last year without any issues.
 

EastCoastGambit

Well-known member
For now I'll just turn the temps lower and lift the pots off the floor. I thought the fans would distribute the heat better to avoid but it's also new and RH is down so plants were not pleased with me.
 

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