Cal? Phos? both?

Jun 30, 2024
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Hi guys- I'd love to get your thoughts on this deficiency I've got on my grow here. This is day 45 of my second grow in a 4x4 living soil coot's mix- I used the take and bake kit from BaS and sourced the compost/peat/etc locally. My first grow also showed bits of this but it was not nearly as pronounced as what you see here. I've had people give me a whole range of possible explanations, but as you all know it can be difficult when many symptoms can present similarly. My first thought was Cal, but the deficiency started in the older leaves which I read is atypical for a cal deficiency. Having now looked at deficiency guide here, I'm thinking Phosphorous might actually be my problem... Is it odd that one half of the plant seems much more affected than the other, which looks pretty healthy?

Any thoughts/suggestions? Should I try and add anything at this point or just ride it out? Thanks!


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I'm running the Build a Soil soil recipe- 33% compost, 33% aeration, 33% peat moss. Added to that is their 'take and bake' recipe, which is supposedly all you need for a fully loaded organic living soil. I added worms as well as Rootwise mycrobe complete microbes.

Up to these pictures, I had been running basically water only- I would add Quillaja as a wetting agent, plus an occasional extra dose of microbes. Since these pictures were taken, I've tried adding CowCal and Epsom salts, as well as a casting tea. I've also fairly recently topdressed with Build-A-Flower. Nothing has had an especially notable effect on the plants.

On average my humidity is ~50% and my leaf temp is ~77f I'm shooting for a vpd of 1.4 currently.

I've got them on a 20/4 light schedule with a dli of ~40/45.
Here are some updated photos from today (day 54). All of these plants seem pretty small to me, but the buds look good idk. This is my second indoor grow- the first was much more volume (the canopy was wall to wall) and while the buds came out pretty good (B+ on my high-bar scale), they didn't look as good at this point.


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Also, just got the results of my soil test back... I'm not entirely sure how to evaluate them but right off the bat it seems my ph is off and my sodium is high... which is odd because I have used exactly 0 non organic neuts.


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