HELP! Is this calcium deficiency?

[Rik]

I have a Northern Lights feminized photoperiod from Sensi Seeds, growing indoors in FFOF soil. She is 30 days from her first leaves, and this is my first go at mainlining.

I’m worried about these spots, is this calcium deficiency?

Any and all help is appreciated! Thank you!

Northern Lights, feminized photoperiod, Sensi Seeds
Day 30 from first leaves
FFOF soil with Fox Farm dirty dozen nutes
5 gallon fabric pot
Black Dog LED PhytoMax-2 600, 615 watts from wall
Temps low to mid 80s during day, low 70s at night
Runoff pH at 6.1, despite me always watering around 6.7 to try to bring it up

 

[3Berries]

I'd be careful adding nutes to FFOF for little ones. Did you add any perlite or limestone to the base mix?

 

[Rik]

Hi 3Berries. There is a bed of perlite at the bottom of the 5 gallon fabric pot. No additional perlite added to the soil, but it comes with a decent amount of perlite already added in. I hear you about not over-feeding nutes, but don’t these spots seem more like a deficiency?

 

[3Berries]

Are you adding any calcium or magnesium? Potassium is usually included in nutes.

My next grow with FFOF will have added perlite to 'dilute' the soil and limestone to add calcium and magnesium plus buffer the soil.

 

[Rik]

I haven’t added any calcium yet. Usually I don’t start adding calmag until I’m about to switch to flower, but I’ll happily start adding calmag now if the consensus is that this is a calcium deficiency. I just don’t know if that’s what the leaves are saying or not…

 

[3Berries]

I struggle with the calcium signs. My latest grow is new soil, ProMix Bx and not hardly fortified at all. I have an auto in it that I'm trying for the first time too. It was looking terrible then I decided it was no calcium as none had been added, no limestone, no top dressing. Started adding some CaCl2 top dressing and it looks a lot better but now may have K issues.

It going in to the home stretch now. The new lower growth looks good. Stuff on top closest to the lights are suffering still.

 

[billyboy]

I believe that it is more concerning that they are clawed. You may want to just water for a few days (pH 7.5 +) and get the pH up a bit and stay away from the nutes until they turn up and the fresh growth can tell you more. They are very green and maybe just shy of a little nitrogen toxicity.

 

[Rik]

Thanks billyboy, I think I might do that. I appreciate the advice.