Please Help with calmag issue?

Newbgrower1 · Jul 25, 2025

Hey guys and gals. I’m having an issue with my bb cheese auto. End of week 2 of flower. I know this has been asked over and over again but I need some urgent help and don’t have the time right now to read through a bunch of posts.
I’m in a 3x3 ac infinity tent with a 300w @18” on power 3. a heater, humidifier, 4” exhaust and two circulating fans. Plant is in a 5ga. Fabric pot with ff hf soil. I added Gaia 2-8-4 to the bottom 3” of the pot and Gaia 4-4-4 to the top. I also added ewc and perlite to the soil before amending with the Gaia. 2 weeks ago I top dressed with a lil more Gaia 2-8-4. I water once every two weeks with epsome salt.(1 tsp) and use tap city water that I let sit for 24 hrs.
Everything was fine a week and a half ago. On Sunday I watered like normal and saw some brown spots on a few leaves. I didn’t catch it till after I watered. calmag-issue-jpeg.2483429/" class="bbImage " width="900" height="1200" layout="intrinsic" alt="Please help with calmag issue">
Wednesday I added calmag to a ga. Of water and watered with a half gallon. Today the leaves are looking way worse. calmag-issue-2-jpg.2483430/" class="bbImage " width="900" height="1200" layout="intrinsic" alt="Please help with calmag issue 2">So in 5 days it went from the first pic to the second. And I added calmag in between. Idk if I should flush next watering then just switch to synthetic nutes or just give it a little more time to see if the calmag helps. Any and all help is appreciated. I need to water tomorrow so ideally id like to get a plan together by then. Tia

Newbgrower1 · Jul 25, 2025

I also have an apple fritter auto in the tent too that’s looking fine. It’s a bout a week or two behind the bb cheese in flowering. The af is in just plain ff hf with ewc, bat guano and perlite. So Idk if I should do the same to the af to prevent this issue or wait to see signs of a calcium deficiency?

Jmaes Mabley · Jul 25, 2025

I also use Gaia Green, and every 2 weeks I top dress the soil with 1 TBLSP Epsom Salts Per Gallon of Soil, and 1 TBLSP per gallon of medium, of Gypsum, every 2 Weeks.

I start my plants out in 18oz Solo cups, and add 1 TSP GG 4-4-4. 1/2 TSP Epsom Salts, unless using tap water. One can probably do without Epsom Salts at this point, as the tap, and Gaia Green, both have Ca/Mg, and enough to sustain a seedling. RO/Distilled water, Id use 1 TSP Gallon water, on seedlings. Every watering. Ca/Mg are critical secondary nutrients, and are a basically as important as NPK.
Also many/most strains Ive grown, grow Ca/Mg hungry right before 3rd week of flowering, and it is best/often critical, to have all you need in the medium, before they even think of needing more. Less is more, but, availability, at the right time, is what is important, so I generally supply Mg/Ca all through the grow, at slightly ever increasing amounts. They get very Mg/Ca hungry in 4- 6th weeks flowering, of an 8-9 weeks strain.

I myself, if growing autos, I would use a container big enough to get it through veg, and I would use the 4-4-4 Gaia Green. Maybe around 30 days, and/or Right before, or right when I determine the plant is flowering, I would transplant it, into a container that is amended with Gaia Green 2-8-4, and 4-4-4 when flowering.
AFter 30 days in bigger container Id reamend with straight 2-8-4. Epsom/Gypsum every 2 weeks.

Sprout phase, ~1 week: NO nutrients are being added to the growing medium. Earth worm castings & cotyledons provide more than enough nutrition for the first 2 weeks of a seeds life
-transplant to 1gallon-
Early veg phase, 4 weeks: amend 3tbsp of 100% All Purpose 4-4-4 per gallon of medium eg. 3tbsp of 4-4-4 for a 1gallon container
Late veg phase if needed, 4 weeks: top dress 3tbsp of 100% All Purpose 4-4-4 per gallon of medium eg. 3tbsp of 4-4-4 for a 1 gallon container
-transplant to 5gallon-
Early flower phase, 1 week before flipping lights: amend 3tbsp of 50% All Purpose 4-4-4 and 50% Power Bloom 2-8-4 per gallon of medium eg. 8tbsp of 4-4-4 and 8tbsp of 2-8-4 for a 5gallon container
Mid flower phase, week 3 or 4 of flower: top dress 3tbsp of 25% All Purpose 4-4-4 and 75% Power Bloom 2-8-4 per gallon of medium eg. 4tbsp of 4-4-4 and 12tbsp of 2-8-4 for a 5gallon container
Late flower phase, sativa plants: if you have a sativa plant chances are they may need an additional weeks of growing time so you could do a light top dress 2tbsp of 100% Power Bloom 2-8-4 per gallon of medium eg. 10tbsp of 100% Power Bloom 2-8-4 for a 5 gallon container.

This is the basic feed schedule and this is a FULL STRENGTH feeding regiment meaning you are pushing your plant pretty hard. Certain strains and different growing environments may mean that you might only need to use 2/3 of what I have here for amounts. I recommend starting off with 2/3 of what is listed and increasing to full amounts if you're certain that your plants can handle it.

Additional supplements that I use are:

Mycorrhizae
I generously dust the root ball EVERY time I transplant and I also add a couple scoops into my soil mix any time I amend some soil to be going into a new container. Do not underestimate your rhizosphere

Epsom Salts - Magnesium Sulfate
LEDs increase the demand for Mg and this helps cover that demand. Overall plant health and nutrient uptake seems to improve when adding 1tbsp of Epsom Salt every 2 weeks

Gypsum - Calcium Sulfate
Decreases soil salinity and improves soil structure while also providing Calcium and Sulfate. 1tbsp of Gypsum every 2 weeks gallon medium

Rock Dust Blend - micronutrients and humic acid I use AZOMITE 1 TBLSP Gallon Medium, every 4 weeks.
Used primarily to supplement micronutrients that may be lacking. Overall plant health and lushness improved since I started adding 2tbsp every 2 weeks

Pretty much once you get started you are either amending or top dressing in 4 week blocks, adding supplemental nutrients every 2 weeks, and then you just water your plants

franklygrown · Jul 25, 2025

Newbgrower1 said:
Hey guys and gals. I’m having an issue with my bb cheese auto. End of week 2 of flower. I know this has been asked over and over again but I need some urgent help and don’t have the time right now to read through a bunch of posts.
I’m in a 3x3 ac infinity tent with a 300w @18” on power 3. a heater, humidifier, 4” exhaust and two circulating fans. Plant is in a 5ga. Fabric pot with ff hf soil. I added Gaia 2-8-4 to the bottom 3” of the pot and Gaia 4-4-4 to the top. I also added ewc and perlite to the soil before amending with the Gaia. 2 weeks ago I top dressed with a lil more Gaia 2-8-4. I water once every two weeks with epsome salt.(1 tsp) and use tap city water that I let sit for 24 hrs.
Everything was fine a week and a half ago. On Sunday I watered like normal and saw some brown spots on a few leaves. I didn’t catch it till after I watered. View attachment 2483429
Wednesday I added calmag to a ga. Of water and watered with a half gallon. Today the leaves are looking way worse. View attachment 2483430So in 5 days it went from the first pic to the second. And I added calmag in between. Idk if I should flush next watering then just switch to synthetic nutes or just give it a little more time to see if the calmag helps. Any and all help is appreciated. I need to water tomorrow so ideally id like to get a plan together by then. Tia

PH? Tap can get base in summer, making the nutes less bioavailable.
I'm asking as a well read novice.

Newbgrower1 · Jul 25, 2025

franklygrown said:
PH? Tap can get base in summer, making the nutes less bioavailable.
I'm asking as a well read novice.

I’ve grown probably close to 50 plants in the past five years or so and I’ve never phd my soil. I’m not saying that’s not the problem but I’d rather just flush the soil then reapply synthetic nutes if the next calmag feeding doesn’t do anything. I have a ph pen but don’t know if or how to calibrate it. I may look into calibration and check my runoff just for reference. Thanks for the reply.

Newbgrower1 · Jul 25, 2025

Jmaes Mabley said:
I also use Gaia Green, and every 2 weeks I top dress the soil with 1 TBLSP Epsom Salts Per Gallon of Soil, and 1 TBLSP per gallon of medium, of Gypsum, every 2 Weeks.

I start my plants out in 18oz Solo cups, and add 1 TSP GG 4-4-4. 1/2 TSP Epsom Salts, unless using tap water. One can probably do without Epsom Salts at this point, as the tap, and Gaia Green, both have Ca/Mg, and enough to sustain a seedling. RO/Distilled water, Id use 1 TSP Gallon water, on seedlings. Every watering. Ca/Mg are critical secondary nutrients, and are a basically as important as NPK.
Also many/most strains Ive grown, grow Ca/Mg hungry right before 3rd week of flowering, and it is best/often critical, to have all you need in the medium, before they even think of needing more. Less is more, but, availability, at the right time, is what is important, so I generally supply Mg/Ca all through the grow, at slightly ever increasing amounts. They get very Mg/Ca hungry in 4- 6th weeks flowering, of an 8-9 weeks strain.

I myself, if growing autos, I would use a container big enough to get it through veg, and I would use the 4-4-4 Gaia Green. Maybe around 30 days, and/or Right before, or right when I determine the plant is flowering, I would transplant it, into a container that is amended with Gaia Green 2-8-4, and 4-4-4 when flowering.
AFter 30 days in bigger container Id reamend with straight 2-8-4. Epsom/Gypsum every 2 weeks.

Sprout phase, ~1 week: NO nutrients are being added to the growing medium. Earth worm castings & cotyledons provide more than enough nutrition for the first 2 weeks of a seeds life
-transplant to 1gallon-
Early veg phase, 4 weeks: amend 3tbsp of 100% All Purpose 4-4-4 per gallon of medium eg. 3tbsp of 4-4-4 for a 1gallon container
Late veg phase if needed, 4 weeks: top dress 3tbsp of 100% All Purpose 4-4-4 per gallon of medium eg. 3tbsp of 4-4-4 for a 1 gallon container
-transplant to 5gallon-
Early flower phase, 1 week before flipping lights: amend 3tbsp of 50% All Purpose 4-4-4 and 50% Power Bloom 2-8-4 per gallon of medium eg. 8tbsp of 4-4-4 and 8tbsp of 2-8-4 for a 5gallon container
Mid flower phase, week 3 or 4 of flower: top dress 3tbsp of 25% All Purpose 4-4-4 and 75% Power Bloom 2-8-4 per gallon of medium eg. 4tbsp of 4-4-4 and 12tbsp of 2-8-4 for a 5gallon container
Late flower phase, sativa plants: if you have a sativa plant chances are they may need an additional weeks of growing time so you could do a light top dress 2tbsp of 100% Power Bloom 2-8-4 per gallon of medium eg. 10tbsp of 100% Power Bloom 2-8-4 for a 5 gallon container.

This is the basic feed schedule and this is a FULL STRENGTH feeding regiment meaning you are pushing your plant pretty hard. Certain strains and different growing environments may mean that you might only need to use 2/3 of what I have here for amounts. I recommend starting off with 2/3 of what is listed and increasing to full amounts if you're certain that your plants can handle it.

Additional supplements that I use are:

Mycorrhizae
I generously dust the root ball EVERY time I transplant and I also add a couple scoops into my soil mix any time I amend some soil to be going into a new container. Do not underestimate your rhizosphere

Epsom Salts - Magnesium Sulfate
LEDs increase the demand for Mg and this helps cover that demand. Overall plant health and nutrient uptake seems to improve when adding 1tbsp of Epsom Salt every 2 weeks

Gypsum - Calcium Sulfate
Decreases soil salinity and improves soil structure while also providing Calcium and Sulfate. 1tbsp of Gypsum every 2 weeks gallon medium

Rock Dust Blend - micronutrients and humic acid I use AZOMITE 1 TBLSP Gallon Medium, every 4 weeks.
Used primarily to supplement micronutrients that may be lacking. Overall plant health and lushness improved since I started adding 2tbsp every 2 weeks

Pretty much once you get started you are either amending or top dressing in 4 week blocks, adding supplemental nutrients every 2 weeks, and then you just water your plants

Thanks for all the info. Do you think it’s possible that it’s in lockout? I really don’t know how it could be. I’ve grown this way for a few years now without much trouble. But it getting worse after I added calmag gets me thinking it’s not the amount of calmag in the soil, it’s more about the intake of the nutrients. But idk that much about lockout.

franklygrown · Jul 25, 2025

Newbgrower1 said:
I’ve grown probably close to 50 plants in the past five years or so and I’ve never phd my soil. I’m not saying that’s not the problem but I’d rather just flush the soil then reapply synthetic nutes if the next calmag feeding doesn’t do anything. I have a ph pen but don’t know if or how to calibrate it. I may look into calibration and check my runoff just for reference. I just double check occasionally with a reagent test to confirm. Here in WNY our water is clear of excessive toxins, but is really hard with minerals (7.8-8.2 ph) Consequently salts/scale builds, staying a bit acidic (low ph) helps.

imgrowing · Jul 25, 2025

as much as i disagree with flushing soil i think that's what i'd do.
as far as ph goes, it's not an issue when using soil. if you consider fox farm soil that is.
sure sounds like lockout to me though.
just my 2 cents

Newbgrower1 · Jul 26, 2025

imgrowing said:
as much as i disagree with flushing soil i think that's what i'd do.
as far as ph goes, it's not an issue when using soil. if you consider fox farm soil that is.
sure sounds like lockout to me though.
just my 2 cents

Thanks. I just ran 2 ga. Of water through it. Hoping it does the trick. I’ll add a lil cal mag next watering on Tuesday.

RoadKillSkunkHunt · Jul 26, 2025

@Newbgrower1

When did you start calmag? During veg?

You'e using Happy Frog. Its well buffered and is probably between 6.0-7.0 soil pH range. )Hopefully closer to 6.5 which is the real sweet spot for soil grows). I'm curious on when you started calmag, how much are you using when you use it and how often you've applied it. I'm inclined to believe you've locked out your soil and calcium isn't available to the plant's use. However since so many leaf issues represent multiple potential problems, we'll still need to dig deeper to get to the "roots" of your problem. Yes, its something in the root zone. I'm going to guess excess of something locking things out.

RoadKillSkunkHunt · Jul 26, 2025

Newbgrower1 said:
I’ve grown probably close to 50 plants in the past five years or so and I’ve never phd my soil. I’m not saying that’s not the problem but I’d rather just flush the soil then reapply synthetic nutes if the next calmag feeding doesn’t do anything. I have a ph pen but don’t know if or how to calibrate it. I may look into calibration and check my runoff just for reference. Thanks for the reply.

Contrary to popular belief, checking pH and ec of your run-off in SOIL really doesn't tell you much. The organics that you flush out alter those readings. Again, the answers are in the details of what you've done most likely .... not what you may have left out.

RoadKillSkunkHunt · Jul 26, 2025

imgrowing said:
as much as i disagree with flushing soil i think that's what i'd do.
as far as ph goes, it's not an issue when using soil. if you consider fox farm soil that is.
sure sounds like lockout to me though.
just my 2 cents

Fox Farm Happy Frog for our purposes is considered soil however, technically, its an organic mix that has zero mineral based soil in it. This is lock-out. Most likely to some degree ... magnesium, potassium, iron, and/or manganese due to too much calcium. (especially K)

Newbgrower1 · Jul 26, 2025

RoadKillSkunkHunt said:
Fox Farm Happy Frog for our purposes is considered soil however, technically, its an organic mix that has zero mineral based soil in it. This is lock-out. Most likely to some degree ... magnesium, potassium, iron, and/or manganese due to too much calcium. (especially K)

Besides the Gaia I haven’t added anything to it so idk why it would be high in calcium I just got done running a photo that I started mid December using the same water. But I used ff nutes instead of Gaia. I’m gonna have to go back and double check to make sure I didn’t add anything else in the beginning. But if I did it would only be bat guano and ewc because that’s all I have for dry amendments.
I did flush it with 2ga. Of water this morning. Hopefully that gets it back on track. I’ll add some calmag next watering on Tuesday then a light synthetic feed on the next watering. I just don’t know how I over fed or what I over fed.its all organic and I thought you couldn’t over feed with organic plus I stayed under the recommended doses for everything. Thanks for the reply. Hopefully I get it figured out.

RoadKillSkunkHunt · Jul 26, 2025

Newbgrower1 said:
Besides the Gaia I haven’t added anything to it so idk why it would be high in calcium I just got done running a photo that I started mid December using the same water. But I used ff nutes instead of Gaia. I’m gonna have to go back and double check to make sure I didn’t add anything else in the beginning. But if I did it would only be bat guano and ewc because that’s all I have for dry amendments.
I did flush it with 2ga. Of water this morning. Hopefully that gets it back on track. I’ll add some calmag next watering on Tuesday then a light synthetic feed on the next watering. I just don’t know how I over fed or what I over fed.its all organic and I thought you couldn’t over feed with organic plus I stayed under the recommended doses for everything. Thanks for the reply. Hopefully I get it figured out.

Indoors in smaller pots, organics can be a struggle. People do it. I used to myself but switched to GH Flora series because of ease of use and consistent results. Organics is a timing game. Microbially speaking, there's a lot more involved in turning organics into plant food and therefore it takes some experience to be consistent with theses timings.

Outdoors in raised bed gardens, much larger containers, or in the ground, organics works wonderfully. Indoors, you would not be the first to struggle. How much calcium is in your tap water? Any idea? That's a leading contributor for some people with naturally hard water sources.

Edit: I also noticed you added gypsum to your soil mix.

LoveGrowingIt · Jul 26, 2025

I've seen similarly appearing leaves when the temperature and humidity were too high. This may not be the problem, but it would help to rule it out. I didn't see the environment status, so I'm asking what it is.

That said, I'm leaning toward agreeing with @RoadKillSkunkHunt about it being lockout.

GNick55 · Jul 26, 2025

Newbgrower1 said:
Hey guys and gals. I’m having an issue with my bb cheese auto. End of week 2 of flower. I know this has been asked over and over again but I need some urgent help and don’t have the time right now to read through a bunch of posts.
I’m in a 3x3 ac infinity tent with a 300w @18” on power 3. a heater, humidifier, 4” exhaust and two circulating fans. Plant is in a 5ga. Fabric pot with ff hf soil. I added Gaia 2-8-4 to the bottom 3” of the pot and Gaia 4-4-4 to the top. I also added ewc and perlite to the soil before amending with the Gaia. 2 weeks ago I top dressed with a lil more Gaia 2-8-4. I water once every two weeks with epsome salt.(1 tsp) and use tap city water that I let sit for 24 hrs.
Everything was fine a week and a half ago. On Sunday I watered like normal and saw some brown spots on a few leaves. I didn’t catch it till after I watered. View attachment 2483429
Wednesday I added calmag to a ga. Of water and watered with a half gallon. Today the leaves are looking way worse. View attachment 2483430So in 5 days it went from the first pic to the second. And I added calmag in between. Idk if I should flush next watering then just switch to synthetic nutes or just give it a little more time to see if the calmag helps. Any and all help is appreciated. I need to water tomorrow so ideally id like to get a plan together by then.

looks like a bit of light stress going on

Newbgrower1 · Jul 26, 2025

LoveGrowingIt said:
I've seen similarly appearing leaves when the temperature and humidity were too high. This may not be the problem, but it would help to rule it out. I didn't see the environment status, so I'm asking what it is.

That said, I'm leaning toward agreeing with @RoadKillSkunkHunt about it

77f and I just lowered it to 60% from 62% vpd goes from 1.15-1.22. I could probably lower my humidity a tad. I have an ac infinity tent with a heater and humidifier. Two circulating fans and a 4” exhaust. I’m thinking it’s in lockout too I just don’t know how. I’m feeling like the soil may have some dry spots in it. Idk if that can cause lockout but I feel like I read that somewhere.
I ran 2 ga. Of water through it this morning hopefully it’s looking better or at least not worse by next watering.

Newbgrower1 · Jul 26, 2025

GNick55 said:
looks like a bit of light stress going on

I have an ac infinity 300w that’s on power 3 about 18” above canopy maybe more. I had it on power 4 for most of the grow but noticed slight whiting on the tips of upper leaves so I lowered it to 3 about a week or two ago. Do you think I should bring it to 2? I have another plant in the tent that’s taller and not showing any signs of stress. Thanks for the help

RoadKillSkunkHunt · Jul 26, 2025

Newbgrower1 said:
77f and I just lowered it to 60% from 62% vpd goes from 1.15-1.22. I could probably lower my humidity a tad. I have an ac infinity tent with a heater and humidifier. Two circulating fans and a 4” exhaust. I’m thinking it’s in lockout too I just don’t know how. I’m feeling like the soil may have some dry spots in it. Idk if that can cause lockout but I feel like I read that somewhere.
I ran 2 ga. Of water through it this morning hopefully it’s looking better or at least not worse by next watering.

Try this ... substitute epsom salts 1 teaspoon per gallon of water. Stop with calmag for now. The leaf damage you already have won't heal. Look at new growth to see if you've fixed the issue.

Newbgrower1 said:
I have an ac infinity 300w that’s on power 3 about 18” above canopy maybe more. I had it on power 4 for most of the grow but noticed slight whiting on the tips of upper leaves so I lowered it to 3 about a week or two ago. Do you think I should bring it to 2? I have another plant in the tent that’s taller and not showing any signs of stress. Thanks for the help

Since you already adjusted light intensity, I probably wouldn't adjust it again.

Newbgrower1 · Jul 26, 2025

RoadKillSkunkHunt said:
Try this ... substitute epsom salts 1 teaspoon per gallon of water. Stop with calmag for now. The leaf damage you already have won't heal. Look at new growth to see if you've fixed the issue.

Since you already adjusted light intensity, I probably wouldn't adjust it again.

I’ve only used calmag once. It was last week when I noticed the brown spots. After using it the problem definitely got worse. I just don’t know if it was already getting worse and timing made it seem like it was the calmag or what. I’ve always used epsome salts in this grow. Usually 1tsp per gallon every other watering or so. Does the epsome need to be flushed do to salt build up? I feel like it’s a calcium deficiency. Just based off progression of the spots on the leaves and where on the plant it started. If I go with just epsome, will I get enough calcium to bring her back? Brown spots started on leaves about halfway up the plant and progressed up the plant. After spots got darker, yellow started to come through. From what I’ve read that’s a calcium deficiency. I really don’t know but that’s what I’m thinking at this point. I just want to make sure that whatever I do I try to do it quick since the yellowing is progressing so fast. Thanks for the help I appreciate it. And I’m in week 3 of flower now. it seems to have stopped its stretch. Only new growth is buds pretty much. Anything to look for in bud development?

Please Help with calmag issue?

Please Help with calmag issue?

Newbgrower1

Newbgrower1

Jmaes Mabley

franklygrown

Newbgrower1

Newbgrower1

franklygrown

imgrowing

Newbgrower1

RoadKillSkunkHunt

RoadKillSkunkHunt

RoadKillSkunkHunt

Newbgrower1

RoadKillSkunkHunt

LoveGrowingIt

GNick55

Newbgrower1

Newbgrower1

RoadKillSkunkHunt

Newbgrower1

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