Blue Dream x GDP - Leaf edges curling up/tacoing/margin curling w/pics

[AppliedScience]

I'm having a bit of trouble figuring out what is causing this margin curling. Its day 36 out of 63 for this GDP x Blue Dream. Im wondering if anyone has seen this specific shape of curling on blue dream or GDP since I have a hunch it may be partially genetic.

It's not under watering - They're in 50/50 coco/pearlite watered 8x a day with 20% runoff. Humidity stays on the high side at 55% RH light on/80% RH lights off.

If it is something I assume its either a magnesium deficiency or high temps.

Leaf zone temps get to 86.5 measured with a IR thermometer (with CO2)

These are getting magnesium from Canna Coco + 1/4 dose (1ml/g) of CAliMAGic.

So what do you guys think? Genetics? Magnesium? Temps?

 

[MountainBudz]

Humidity is in check, definitely not that. What is your average temperatures running?

 

[MountainBudz]

I have seen this caused by high temperatures a few times and being a bit deficient in magnesium as well. Even if your temps are high, if you give them a light foliar feed of epsom salts you may see them improve some. Maybe even add a teaspoon in your next feedibg/ watering as well. Definitely won't hurt.

 

[Absolem]

Just throwing it out there. Perlite has little to no cec capacity. So if you are growing in a 2 gallon bag you really only have one gallon of coco and it's high cec exchange to hold and release nutrient ions.

 

[AppliedScience]

Humidity is in check, definitely not that. What is your average temperatures running?

Running at 86.5f all the time with a gavita mater lighting controller dimming them so they never go above 87f.

I have seen this caused by high temperatures a few times and being a bit deficient in magnesium as well. Even if your temps are high, if you give them a light foliar feed of epsom salts you may see them improve some. Maybe even add a teaspoon in your next feedibg/ watering as well. Definitely won't hurt.

Thanks for the advice, I'll set my temperature threshold a degree lower and give them a little epsom salt. I assume its probably to late to foliar at week 5, do you have an exact measurment for how much to put in for a feeding?

Just throwing it out there. Perlite has little to no cec capacity. So if you are growing in a 2 gallon bag you really only have one gallon of coco and it's high cec exchange to hold and release nutrient ions.

Yup, that is true. Since pearlite also holds almost no water in comparison to coco coir, the overall CEC should remain almost as high as plain coco. You effectively hold less water, but have more available oxygen for the roots. You might already be saying this in less words, but I figured I would clarify in case you weren't.