Spots on leaves

[Gwrgenau]

Problem: Brown spots on outside of leaves on one plant

Medium/grow method: Coco-Loco with perlite

Feed: and supplements used: per gal - Dyna-Gro : Bloom - 2ml ; Grow - 1ml ; ProTekt-Silicone - 1 ml ; Cal-Mag - 1ml - PH 6.0

water source: tap - sit our for 48 hours

Strain/age: close to done

light used: 2 - Vipar Spectra 450w

Climate: grow tent - 70 - 75 F ; 30 - 35% RH

Additional info: Have three AWW plants in day 55 from planting in Coco.. 1 week in starter pods. dont see anything on two plants and yesterday started noticing this on the one plant.. cut off 4 leaves.. more today.

TIA for any suggestions.

GW

 

[Waira]

- How are you running this coco, drain-to-waste? Any info on pH and ppm's going in, and coming out? ...if you're running it like you would true soil, you're in for a rough ride; coco is specialized "hydro" medium, a lot of do's and don't's, more so than other soilless mediums like peat based Pro-Mix....
Nute solution looks a bit mild, but that's why you need a TDS/EC reading, to see how rich this really is,...
I need whole plant pics too for better diagnostics...
First impression is this is Ca defc., a likely cause because of the coco's high CEC binding of Ca++ to itself, making it unavailable to the plant... coco needs to be sated first with Ca before it starts to give and take normally, hence the need usually for elevated Ca-Mg...
pH is critical! this affects availability most of all, and in coco, is best around 6.0...
In pots like this, typically the plants are a feed often, mild solutions, with the run-off ppm and pH tested to make sure there's no nute salts loading up in there, and the pH is in range.... 15-20+% run-off each time purges build ups, restore balance of nutes too....