What is this leaf problem?

[echdk3]

Hey guys, my girls are in day 44 since the flip to 12/12, and I’ve got some discoloration in some of my leaves. Can you guys suggest what might be going on?

These are two Girl Scout Cookies photos from Nirvana Seed Shop, grown in FFOF and perlite with FF dirty dozen nutes (I’ve done full strength dosing from the start, so could this be nutrient burn?) grown under a Black Dog LED PhytoMAX-2 600 (630 watts from the wall) in a tent. Temps range from upper 60s with lights off to mid-upper 70s with lights on. Humidity ranges from about 38% to 44%, which is the highest I can get it with two humidifiers running 24/7 and the house furnaces running super hard because it’s freaking freezing outside.

[homegrown]

looks like calcium deficiency.

[echdk3]

Thanks homegrown! If this were yours, would you add some cal-mag? Any harm in doing so if it turned out not to be a calcium deficiency?

[homegrown]

Shouldn’t have a problem, I add cal-mag to every feeding.

[YYCannabis]

Phosphorus deficiency. Red veins/stems. Leaves look thick and the green is deepening. She is probably going into “final push”. Phosphorus peaks just as she reaches maximum bud size. Now she will really start squeezing little diamonds out. 👍

[echdk3]

Nice! So nothing for me to do at this point and it’s normal? Am I likely a few weeks away from harvest? Homegrown suggested calcium deficiency, is there any harm in adding some cal-mag at this point? Thanks for your valuable input!

[YYCannabis]

I add cal-mag through the entire grow. I haven’t seen any issue with doin so.