Deficiency appeared overnight - Potassium? Calcium?

Hi folks

I have four Nirvana Bubblicious a couple of weeks old, they have been the picture of health so far. Then this morning I notice a problem with them that has appeared since last night - there are brown spots on the edges of the leaves and overall they have lost their healthy glow.

They were fed yesterday with Canna Start, Grotek Humic Acid, Kay's Seaweed Extract and Maxicrop Take Root at ec 1.4, ph 6.2, seems to me something about this feeding was not to their liking, which is strange as they have been getting the same feed, just at a lower strength slightly since they had their first true leaves.

I've checked the complete guide thread and looks to me like it could be calcium deficiency, or potassium deficiency caused by ph lockout.

These same brown spots on the edges of the leaves has also shown up on my clones as well, and those were fine yesterday too!

If this is Calcium deficiency, would a dose of Calcium Nitrate cure it? It is 15.5% N and 26.6% Ca.

it could be a deficency. but it looks more like trouble with your ph to me.

Wouldn't there be some spotting on the front part of the leaflets if it was PH? I'll keep an eye on it, maybe my ph meter needs recalibrating.

some of the pics do show signs of k,deficency if i was you i would keep an eye on ph. and if it does get to cold.it can effect k,uptake

For one it looks like a HARDY plant, most plants wouldn't react that kindly. It looks like over watering and nute burn. I think letting what you did feed take hold and let the roots recover. Plants react badly to nutrients when they do not have nice fluffy roots.

That is a very hardy plant and different strains react uniquely to nutrient compositions. 6.2 is a bit strong as well, that might be why the N is burning the plants and locking out other nutrients.

Temps are steady. I've just noticed the same dead spots have appeared on some of my plants on flower, but less severe. I think the batch of seaweed extract I made up from powder is at fault as nothing else has been changed. It's a local brand and I've used the liquid version for years with great success, just ran out of that and have a 350g tub of the powdered version.

I shall stop using it and see if the problem goes away. Then I will take a healthy cloen and feed it with the seaweed and see if it gets these spots.

All in all, a wierd problem I've not seen before.

Might have to go get a bottle of Maxicrop.

indeed sounds like a good experment.also rh can lock out k, i saw some purple stems on those fanleafs. but that could be a number of differnt reasons