Can somebody confirm this is CalMag deficiency please?

I noticed a few yellow spots onMonday and thought it was leaf Septoria. The yellow spots do not rub off but are spreading.

I am using fox farm HF and just started using CalMag on Monday at 4ml/gal. The water is RO with and adjusted pH of 6.5. I can’t think of anything else. Except I started to CalMag too late.

Strain; Type, Bag

Soil in pots, Hydroponic, or Coco?

System type?

PH of runoff or solution in reservoir?

What is strength of nutrient mix? EC, or TDS

Indoor or Outdoor

Light system, size?

Temps; Day, Night

Humidity; Day, Night

Ventilation system; Yes, No, Size

AC, Humidifier, De-humidifier,

Co2; Yes, No

If you can, upload a picture of your plant. It helps the diagnosis, if needed.

Please upload a picture
And fill out answers to the list of questions above.



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This never up.loaded all my finished info. I think I need to upload from a pac and not a tablet. Sorry everyone.

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What’s the soil slurry? Or ppm in and ppm out?

May 13

What’s the soil slurry? Or ppm in and ppm out?

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The TDS going in is 430 PPM. That is with the cal CalMag adjusted to 6.5pH.

I have not measured output slurry. I was overwatering in begging as little seed in 2 gal fabric pot was easy to do. If you are a moderator you can delete thread and I will start over sorry

I have not measured soil

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I am not a moderator but I and others can follow just fine.

Your best bet is to do a soil slurry with distilled water, what’s the tds and ph? (YouTube how to do one or google)

Also did you get your plants wet is that a chance it is water droplet damage after the led light was magnified through the droplet to burn the leaf?

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Welcome ! My first thoughts I can see water droplets on the leafs. If the light is pretty strong could be magnifying through water droplets to burn the little spots.

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I did get the leafs wet I will do a slurry test next time it is watered. Thank you


It may be water damage from the leafs but a slurry test will give us a good bit of information.

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Just a late reply. Even though the plant was only two weeks sprouted I was using RO water with no CalMag. I feel the FFHF is lacking that nutrient. If not the GGAF#4 is hungry for that nutrient. Hope this might help somebody. Stay safe

That’s why you grow in fox farms ocean forest with a centre plug of happy frog.

All soils eventually need feeding unless your in a 20 glon or bigger pot, read soil slurry or run off to know when to feed.

Yeah, I thought the hard part was popping the seed. I will publish a list of top ten things not to do as a new grower when this is done. Thanks