mid flower leaf edge roll

alriiigghhht....

the skinny:
White Widow
flowering for 4.5 weeks
5 gal Coir/Perlite 80/20
Canna Coco base plus Boost and Cannazym (every other feed) @ 5.8 pH on alternating feed/water schedule. some times if too moist i'll wait a day to let them dry out completely.
600w hps air cooled @ 1.5ft (has been at this for four weeks. problem just started.)
temps at tops 82 degrees F
relative humidity 43-47 (fluctuates constantly)
supplement with CO2 in accordance with manufacturers directions

the slippy:
noticed leaf roll three days ago. assuming mg and began supplementing with calmag. just wonder what you guys think.

also, started pk 13/14 two days ago. i run a pretty high ppm with these girls. consistently at 1800 ppm for three weeks now with no sign of burn (i know it's high, but it's also what they can handle so i use it.). when i supplemented with the pk 13/14 ppm spiked to almost 2000. this is a little alarming. no sign of burning, but i am considering toning down the base nutes to half while using the 13/14. i'm gonna check the media for ppm before the next feeding.

what do you guys think? anyone have experience with pk 13/14? what's your recommended method of applicaiton?

jonathanfrost said:

i'm gonna check the media for ppm before the next feeding. what do you guys think? anyone have experience with pk 13/14? what's your recommended method of applicaiton?

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I used pk 13/14 but stopped doing it cause i didn't see a difference in yield. 2000ppm is a damn high value. High risk of nute burn. Watch your media closely to avoid salt builtup. Also the temperature is a bit too high. 75F is a better.

i agree, man. 2000 ppm is extremely high. like i said, i'm gonna get it down on the next feed. 82 degrees is low with co2. 86-90 F is perfect threshold for co2 uptake. this is argued, but look in any horticulture book you will see those numbers are dead on.

jonathanfrost said:

86-90 F is perfect threshold for co2 uptake. this is argued, but look in any horticulture book you will see those numbers are dead on.

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Yeah it's been argued. Different people tell different stories. As soon as it works out for you it's fine. Good luck for your grow!

lol. exactly, man. thanks, broski!

you're welcome

2000 PPM @ what conversion ? That would be my question .. Wanted to point out that allowing your coco to dry out like so will create havoc .. This leaf roll is commonly seen when calcium uptake is limited due to under watering and it can also indicate that the plant is under waterd .. Avoiding such is even more applicable with CO2

i'm not sure which conversion, broski. 2.8 EC on a milwaukee pen and i use a chart i printed some time ago for conversion it doesn't say which conversion. plants never showed a definite sign of burn, but i still lowered EC to 2.0, began supplementing with calmg and increased water frequency (as per a friends recommendation) yet leaf curl has persisted. flowers are thriving and huge. right on schedule. not sure what the deal is with the leaf curl, but i really can't complain as the plants are thrivingly healthy and have produced some amazing buds.

these pics were shot a week ago (5 weeks into flowering).

Leaf roll = nitrogen overdose. No surprise at the PPM listed.