HELP! Small Dark Spots Developing on Older/Larger Leaves

[dkong399]

Over the past few days, older and larger leaves have been developing small dark spots, with a lighter green halo around the spots. Mostly developing on the older larger leaves, but have also noticed it on some smaller leafs near the top (but not sugar leafs). Is this something to be worried about, or is it natural for these older larger leaves to go through this?

Day 32 of flower, in organic soil, 5 gallon fabric pot, 315w CMH 18-19" away from canopy, 3x3 tent, Day temps 75-80/ 40% RH, Night temps 65-68/ 45-50% RH. Have been feeding BioCanna line every other watering (Bioflores, BioRhizotonic, Bioboost) according to their grow guide - although, I have been using Ph up because it ph's at ~4.7 when I mix their products.

Thank you for your help! Let me know if I can provide any other info.

[Gingerbeard]

I was having the same thing. For me, it was a shot of CalMag. No new spots.

But check the underside of the leaves, just in case. Always check the undersides of the leaves.

Check out calcium and magnesium deficiencies.

https://www.growweedeasy.com/cannabis-symptoms-pictures

[dkong399]

Thanks Gingerbeard! It definitely looks like calcium deficiency, and I've read that calcium uptake increases around this time so it'd make sense. I just get thrown off because the spots are mostly on the older leaves, but the article below says it usually affects newer leaves first.

https://www.growweedeasy.com/cannabis-plant-problems/calcium-deficiency

[Gingerbeard]

I might have had some on newer leaves that were down low. It was my lower and middle fans that took the brunt of it.
Nitrogen, too. If you're yellowing, give them nitrogen.