Heat / light stress or a deficiency?

[MichiGreen]

I know it's already dead, but I did some research out of curiosity...
III. Antagonism between Potassium, Magnesium and Calcium ( by Svend Tage Jakobsen )
"If a larger amount of potassium is applied than removed by the crop, potassium is accumulated in the soil and this leads to an antagonistic effect on the uptake of magnesium and calcium." --

If you've heard of Nector For The Gods nutrients, you might have tried a "Herculean Harvest Flush" to clear out excess nutrients in the soil (it's liquid bone meal). Then resume feeding with your mild nutrient.

 

[MIAutomatic]

Probably too late to help, but I think you have been getting bad advice here. If that plant has any kind of deficiency it is due to lock out, not any type of true deficiency.

Based on everything you have said and the look of that plant I would say that you have killed it with nutrient salts. It looks pretty far gone and it it does recover it will take a very long time to finish and the quality will likely be poor with harsh smoke.

Bin it and start over.
Understand your inputs better and learn from this mistake.

good luck!

 

[Delps8]

I'm a DWC grower so I know very little about soil but 4 plants in one bucket with one feeding sounds like a struggle. Was the pot big enough for that many plants?

What was the quality of the soil mix? I didn't see that mentioned.

The OP said there was one feeding and then "pure tap water". No doubt, but what was in the tap water? The tap water in my house ranges from an EC 0.3 to 0.6. What was the TDS for the OP's tap water and how much would that have put the nute uptake out of whack?

What was the watering process? My understanding is that there's a technique to watering to get the roots to spread out and down. If that wasn't done, how would that impact the plant especially if there were 4 good-sized plants in one pot?

What about temperature and RH and VPD?
If your VPD changes is low, plants can't uptake nutes. Was there a sudden change?

The plants died pretty quickly. On 10/16 they look OK and they were gone about a week later. At first, the leaves were drooping and isn't that a sign of over watering? Dunno - the roots for my plants are underwater.

Sorry to see this happen.

 

[Sleeper143]

I’ve been growing in biobizz light mix soil for 3 years. You mentioned in one of your posts that you ph’d your water down to 6, then added your nutes, then watered your plant. The nutes would change the ph of your already adjusted water again. Maybe you mis-described and do it this way, but you should add your nutes to your water first, then ph to around 6.5 - 6.8 (for soil, lower for coco) before you water the plant.