Is this a cal mag thing?

I am on week 8 of my second grow, and a lot of leaves are turning yellow rapidly and I have a few rust spots on one or two leaves. This started last week, bought some cal mag and gave it to it on its watering day and it seemed to help, after a 3 days More yellowing had occurred so I gave it more cal mag with its feeding. Any idea what I’m doing wrong? I may be over reacting because it has only been a day since I gave it the last cal mag dose but the yellowing scares me

Been getting burnt tips for a while now

Blueberry gusto autoflower

Fox farms happy frog soil

Light is tsw2000 run at 100% about a foot and half above canopy

Feeding fox farms trio at 1/3- 1/2 strength

(Last feeding was 18ml bb, 8ml gb, 18ml tigerbloom all in 2.5 gal)

Watering every other feed,

ph 6.0-6.3 for feeding and watering

Feed/water every 2 or 3 days



Low stress trained during veg

Light defoliation every now and again


Looks more like a general underfeeding.
Your pH is a bit low. Shoot for 6.8
Do the yellow leaves fall off easily or are they hard to pull off?


They do not come off easy, i thought the burnt tips meant I was OVERfeeding, I have no idea tho, only my second grow

The burned tips can be nute burn, but it can also be over watering. Especially when you see it along the edges like in yours. Since the leaves are strongly attached my guess is probably a bit of overwatering. Next time you feel ready to water try to lift the pot slightly and see if it is light. Might be able to go and extra day. Adjusting the pH to 6.8 may be just the thing you need. Some nutrients are not available in soil when you get too low.

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Hey @Payton plants are looking good. I think @Spiney_norman has it. Your pH should be a bit higher like around 6.8.
Take a look at this chart for nutrient availability in soil at 6.8 pH compared to 6.0.


Also consider using beneficial microbes help absorption of nutrients protect against bad microbes from invading your root system.
Once I found this, I use Hydroguard for my DWC hydroponic system, my grows have been substantially better throughout.

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I’m guessing overwater, underfeeding and slightly low pH. I’d go +1/2 strength and every watering feed for a few weeks. Also I like to prune lower larfy growth so the plant doesn’t have to work that hard distributing nutes that can go up top where the party is!


Each on its own would only give a slight problem. But together it adds up.
Its an easy fix tho.