Cal/mag deficiency during flower (support ticket)

I’ve researched and believe this is a cal/mag deficiency. One thing I’ve learned is too much cal may cause overproduction of nitrogen (not good during flower).
This AF girl is going into her 4th week of flowering.
I need some experienced advise about what needs to be done to save this harvest.


Are you already feeding her CalMag? If so, how much?

What nute line are you using?

I would fill out a support ticket and get us a pic of the whole plant.

Too much Calmag yes, none doesn’t work either. Looks like either calcium or magnesium deficiency, both, or wind burn. Support ticket needed.
COPY/PASTE the below list into your forum post.

Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so; Or post
NA (non applicable)

-What strain, Seed bank, or bag seed (photo or auto)
-Age of plant/what week of flower
-Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF
-Vessels: Pots, Grow beds, Buckets, fabric pots
-PH and TDS of Water, Solution, runoff (if Applicable)
-PPM/TDS or EC of nutrient solution if applicable
-Method used to measure PH and TDS
-Indoor or Outdoor if indoor, size of grow space
-Light system LED, MH/HPS/CMH/Fluorescents, or other
-Actual wattage draw of lights
-Current Light Schedule
-Temps; Day, Night
-Humidity; Day, Night
-Ventilation system; Yes, No, Size
-AC, Humidifier, De-humidifier,
-Co2; Yes, No

This is not right. Calmag contains nitrogen usually 2-0-0 or 4.5-0-0. Over use during flower is not recommended. Underuse also not recommended. Plants cannot produce nitrogen.

I can’t seem to find how to fill out a support ticket so here is the grow data:
GG AF germinated in peat pots and transplanted to 5 gal fabric pots made up with with bottom 1/3 of Nature’s Living Soils mixed as directed and top 2/3 miracle gro performance organics container mix on 6/3.
Lighting is Koscheal full spectrum 2000W LED kept 12-18” above plant top thru out grow. Constant fan on low, temps avg 70-78F, and the maintained 60-70%. Watering with store bought pure mountain spring water thru out grow. No nutrient feeding because we’re looking for the seed/water/harvest possibility using the NLS.
Lighting and fan on 18/6, watered every other day, averaging 1 quart per drink in the AM.
Flowering was noted 7/5 give a day or 2. One or 2 mid-level fan leaves were noticed with the rusty brown spots about 2 weeks ago. Now it looks like it’s spreading during mid flowering.

What is advised to do to save my harvest?

-What strain? Gorilla Glue from ILGM
-Age of plant/what week of flower? 63 days old from germination, middle of 4th week of flower
-Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF? Natures Living Soils with Miracle-gro Perfofmance Organics container mix
-Vessels: Pots, Grow beds, Buckets, fabric pots? 5 gal fabric pot
-PH and TDS of Water, Solution, runoff (if Applicable)? UNKNOWN
-PPM/TDS or EC of nutrient solution if applicable? N/A
-Method used to measure PH and TDS? NONE
-Indoor or Outdoor if indoor, size of grow space? Indoor, 2’x3’x7’ open closer
-Light system LED, MH/HPS/CMH/Fluorescents, or other? Full spectrum LED
-Actual wattage draw of lights? UNKNOWN, product literature claims 554 ppfd @18
-Actual wattage draw of lights
-Current Light Schedule? 18 on, 6 off
-Temps; Day, Night? 70F-80F
-Humidity; Day, Night? 60-70%
-Ventilation system; ? Yes, Size 6” carbon filter
-AC, Humidifier, De-humidifier? Yes, both
-Co2;? No

Calmag can have nitrogen in it for sure. I noticed foxfarms version is a 1-0-0 instead of the usual 2-0-0 like “calmag plus” that i bought through amazon:

Curious to see what the conclusion is here. I’m using the same super soil. Just into week 3 of flowering and I have the same markings, leaf tips pointing down. I was adding calmag but read on my bottle that it contains nitrogen so I knocked that off. My diagnoses on my plant and on yours would be too much nitrogen. Was considering a flush but I’m worried that would flush out all the nutrients in the super soil? I might reach out to Natures Living Soil to see what they say. I see you’re using a miracle grow product but I am not but showing the same signs on my plant.

1st place I would start is to find out the ph of the water your giving them

@PCM I got a response from the company and they requested a photo so I sent them yours. I will let you know what they say.


Their response.

Looks to be a CalMag issue… do a mini flush. Add water with a half dose of calmag and adjust to ph of 6.5 and pour until 1/3 to 1/2 of the container (pot) volume has run off or it is running clear, whichever comes first.

Thanks for the help!

I’m gonna try to find a calmag nute with as low a nitrogen content as possible and flush like your response says.
Thanks again for your help and advice.

Not a problem at all. I’m currently doing the same to my girl. I’ll let you know the results

If calcium and magnesium are both required throughout the lifecycle…. Just a thought: you don’t have to add nitrogen with your calcium or magnesium. You can add dolomitic lime, calcium chloride, calcium sulfate, etc. + magnesium sulfate. Using these along with a microbial to help the plant make the ion exchange would probably be even better. ….along with spraying it on the foliage. I like to use phosphoric acid to adjust pH down which adds a bit of phosphorous that can’t be bad during flower.

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I flushed mine last night with the calmag I had. I did order the calmag that @beardless suggested as it has the lowest nitrogen content I could find in calmag.

She had a low runoff PH at first runoff of 6.1. Finished at 6.4. I’ve never done a flush before (even a mini flush) so I’m not sure how long it takes before the plant reacts but this morning the leaf tips were still pointing down when I left. I emailed the company back (as they asked me to) and let them know what’s going on now. Will let you know what they suggest moving forward.

GH CaliMagic is popular and widely used because of its low N content.
Quick note - if you water / feed to adequate runoff each time I kinda view it as a mini-mini flush. Good amount runoff helps prevent nutrients from accumulating faster that they would otherwise. Good luck

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Yeah, I had been doing that but on the ‘grow weed easy’ guide for this stuff, it says you only want to water to runoff until 30 days. After that, no more runoff. Odd…goes against what I’ve read everywhere else.

@PCM - Gave the company my update and they replied with this:

"What are your temps like? Keep adding the calmag at watering. What you should see in the next few days is the stopping of the spread. Add some unsulphered molasses as well. (2 tbsp/gal)

Then he also said in another email:

"BTW do you have any concentrate left? You might want to add 2 tbsp per gallon of water. And yes, adjust your pH to 6.5-6.8 before pouring (once everything you add has been added)

And in a final email:

“Heat might be getting to them slightly and the pH was on the low side which may have inhibited calcium uptake. but it looks like you should be fine.”

They will not return back to a normal look. You will want to look to new growth to determine if it worked. You can add calcium and magnesium without adding nitrogen by amending your soil with lime. (Not hydrated lime) this will raise your soil ph over time, however.


I have had same problem add um 1 tablespoon every water every feeding mixed in one gallon and my plants went from spotty to happy sometimes I had to use two tablespoons ph ro water to 6.4to6.8 and


Everyone is giving good advice and it will help. As a newbie I did not have the equipment to check water or soil PH. It’s on the way now! Funny thing is that I have another plant, “Squirrel Girl “ exact same potting soil, super soil, same water. Only difference is “Squirrel Girl” is living in her fabric pot outside. All is well with her.