Potassium deficiency??

[TheHappyChemist]

Hi growers, First time poster from South East Australia.

I'm growing in pots outdoors in the Australian sun.
The Strain is Barneys Farm CBD Blue Shark (Indica dom) and she's at the end of 2nd week of flowering.
Growing medium: Organic soil (mix of worm castings, mushroom compost, organic soil, sand, perlite)
Feeding: Water with compost tea and Charlie Carp (10.2.6) when required. A week prior to flowering I reduced the Charlie Carp and began weekly feeds of Manutec Liquid Potash (0.2.14).
PH around 6.2.
Height is short of one metre (approx 3 foot). Pot size around 15 litres (4 gallon)

Pictures show the story with problems arising after flowering begun.
Curling under of leaves and their tips. Necrosis mainly but not exclusively to older fans. Affected leaves break away from the stem/branch easily. Plant with minor chlorosis (leaves were greener weeks back). Bud sites appear healthy. My research points to a K deficiency.

I've never grown an Indica dom plant before and i understand they need plenty of K due to their faster flowering stage.
I'm also growing a Malawi Sativa under same feeding/watering which has just begun flowering. No problems with her.

Any help with confirming my fears and solution to solving it? eg.Increase Liquid Potash??

Thanks

 

[thejact55]

I think it is a phosphorus deficiency, not potassium. This happens at times early in flower. Curling leaves and this coloration, along with the fact they are new to flowering points me to this conclusion Slowly up your P fertilizer, I am not a fan of giving them a super dose, and risking either burning a fragile plant or locking out other nutrients. I don't use liquid ferts, so if it was me I would make up an earthworm tea with fish bone meal as a heavy ingredient.

I could be wrong, I don't often have these issues, so my personal experience is limited. But I feel decently about this advice.

Ps- if you post this in the infirmary you might get a better response. Also, I think the last sticky in that forum shows all the deficiencies, take a look at that.

 

[noyd666]

 

[who dat is]

I think it is a phosphorus deficiency, not potassium. This happens at times early in flower. Curling leaves and this coloration, along with the fact they are new to flowering points me to this conclusion Slowly up your P fertilizer, I am not a fan of giving them a super dose, and risking either burning a fragile plant or locking out other nutrients. I don't use liquid ferts, so if it was me I would make up an earthworm tea with fish bone meal as a heavy ingredient.

I could be wrong, I don't often have these issues, so my personal experience is limited. But I feel decently about this advice.

Ps- if you post this in the infirmary you might get a better response. Also, I think the last sticky in that forum shows all the deficiencies, take a look at that.

My vote is for a Phosphorous deficiency as well.

When thinking of a Potassium deficiency imagine an over ripe banana with the lower leaves showing signs first. This picture of bananas below is analogous to the signs and progression of a K deficiency in cannabis plants.

 

[TheHappyChemist]

thanks for the replies. i've re-established the thread in the infirmary.