I'm doing something pretty silly, but I'm actually super excited to see what happens.

Grow School: more info on growing cannabis in coco

A week back I noticed signs of deficiency, with reasonable confidence it's magnesium specifically. My growing medium of coir is notorious for it's tendency to 'steal' Calcium and Magnesium from plants. CocoForCannabis.com is a great resource for the exact science behind coir's behavior, and more importantly how we can buffer the medium to force the swapping existing salts for a heavy dose of calmag that bonds better to the coir, and prevents it from stealing any from your nutes.

Anyway I thought I done did a good job buffering before I read the aforementioned book site (free on kindle unlimited!) turns out my calmag flush's dose was way too low, and way too short.

So, sad plants, but already weeks in, what do we do?

The symptoms are now emerging on all the plants in this batch of coir, increasing calmag feed over the week seems to have slowed spread, but not stopped it.

F! it, we'll live buffer.

I created some ph'ed water with ~150% (7ml/gal) calmag dose, cocoforcannabis says 100% is fine, but they use an 8 hour soak. (I am reasonably confident soaking plant in that much salt for 8 hours would kill it). So i'm aiming for a slightly higher concentrate and shorter duration for the cation exchange sites to swap salts without the plant loosing all her water to the super salty concentrate.

I soaked it for 2 hours, as you see in the photo. After that I set it on riser to drain thoroughly before returning to the autopot for regular fertigation.