Calcium deficiency or light burn?

Godfather10 · Sep 25, 2025

Hello fellow growers. I have a question and hoping I can get an answer. I am currently growing two plants Girl Scout cookies extreme. One plan is doing extremely well actually both are one is a little taller than the other. The taller one though I am getting yellowing of the leaves, it is currently in flowering stage. Do not know what to use to correct the problem and if it is going to affect the plant. I am very confident that it is not caused by the lights. The lights are currently about 18 inches to 24 inches above the tallest stem. I am thinking that it is a calcium deficiency from what I have researched. Has anybody ever experienced this and what did she do to resolve it?

Godfather10 · Sep 25, 2025

Should I remove the affected leaves

Smokey_LaFleur · Sep 25, 2025

What growing medium are you using? Watering/feeding practices? Environmental conditions?

Godfather10 · Sep 25, 2025

Using a 5x5 AC Infinity grow tent humidity is set at 53% , light schedule is 12 hours on 12 hours off . Fox farm happy frog soil in 5 gallon fabric pots feeding every 3 days . Using iglm flower time fertilizer every other watering. Lights are about 24inches above the plants

Justlovetogrow · Sep 25, 2025

Looks more like a potassium deficiency to me but I could be wrong

Week4Bytch · Sep 25, 2025

Justlovetogrow said:
Looks more like a potassium deficiency to me but I could be wrong

Was thinking the same. Have the exact same thing "just" barely showing up on one of my plants.

GNick55 · Sep 25, 2025

raise your light to 35-36 inches from tops

Godfather10 · Sep 26, 2025

This is my first grow so I could be wrong . I really don’t know What do you suggest to correct the problem

Godfather10 · Sep 26, 2025

Should I remove the yellowing leaves

GNick55 · Sep 27, 2025

Godfather10 said:
Should I remove the yellowing leaves

not yet,.

Godfather10 · Sep 27, 2025

What do you recommend to correct the potassium deficiency? What nutrients has schedule should I use?

GNick55 · Sep 27, 2025

Godfather10 said:
What do you recommend to correct the potassium deficiency? What nutrients has schedule should I use?

raise your light,.
it’s light stress,.

KG1 · Sep 27, 2025

Godfather10 said:
Using a 5x5 AC Infinity grow tent humidity is set at 53% , light schedule is 12 hours on 12 hours off . Fox farm happy frog soil in 5 gallon fabric pots feeding every 3 days . Using iglm flower time fertilizer every other watering. Lights are about 24inches above the plants

I feel humidity is overrated dont set extraction to that, is that the probe dandling under the lights, place elsewhere it will read too much light radiation and heat up even worse closer you get to light.

Iglm flower is 10-40-13 so really not something I would use on its own or more than once or twice during say mid flower. A good grower will prosper with simple balanced npks 5-4-3 then 3-4-5. Bloom boosters caused more problems than solved,

I don't like to point any fan at any plant, most make it feel like a windy day, too much for direct use.

The other plant looks a lot greener possibly the difference and issue is between the two and identifiable by you somewhat.

Smokey_LaFleur · Sep 27, 2025

I'm not saying it is not light stress, but wouldn't it be worse farther up the plant? Looks like its kinda scattered. What are you feeding every three days? I'm not familiar with flower time. What wattage is the light?

Week4Bytch · Sep 27, 2025

Your lower plant is starting to get it too ..

Godfather10 · Sep 27, 2025

Light Ian evo 8 -750 watt led light frame not sure if it’s manufactured by Samsung or uses Samsung diodes. As far nutrients, I am using Bergman‘s plant food stage three flower time fertilizer NPK 16 6 30.fertilizer is from IGM website. as far as the height of the light, it is 26 inches above the highest point of my tallest plant and it cannot be raised any higher.

KG1 · Sep 27, 2025

In reference to light wind is in a mexican standoff with it. Too much or too little will emulate light stress.

Indoors wind is possibly the most important factor as mostly it's why constant and in a more finer range than the intermittent outdoors.

For a metric most plants studied were in the 0.5 to 1.0 meters per second wind speed which to measure is darn hard and to perceive physically feels like a very gentle breeze on your skin barely enough to rustle the odd leaf.

At some point growers are going to adopt anemometers (expensive ones that can read wind speeds this low as traditional fan driven ones won't turn at this level) and start being more precise with air speed. Can't wait for that to happen

But yes why is it you have a green plant next to a problem plant, has it just been moved into that tent? Is the plant in front shading it from that fan? Was it on a different fertilizer regime or until recently? Different watering idk but seems like a cool riddle to solve

Smokey_LaFleur · Sep 27, 2025

What power level do you have your light set to? I'm thinking some kind of ph or uptake issue. But, I use "living soil" and don't have a lot of experience using ferts throughout grows. Are these liquid fertilizers?

Godfather10 · Sep 27, 2025

KG1 said:
In reference to light wind is in a mexican standoff with it. Too much or too little will emulate light stress.

Indoors wind is possibly the most important factor as mostly it's why constant and in a more finer range than the intermittent outdoors.

For a metric most plants studied were in the 0.5 to 1.0 meters per second wind speed which to measure is darn hard and to perceive physically feels like a very gentle breeze on your skin barely enough to rustle the odd leaf.

At some point growers are going to adopt anemometers (expensive ones that can read wind speeds this low as traditional fan driven ones won't turn at this level) and start being more precise with air speed. Can't wait for that to happen

But yes why is it you have a green plant next to a problem plant, has it just been moved into that tent? Is the plant in front shading it from that fan? Was it on a different fertilizer regime or until recently? Different watering idk but seems like a cool riddle to solve

Makes sense the affected plant is blocking the smaller plant. Going to try turning down fan speed right now I have it. I think it is like an eight out of a possible 10 gonna turn it down to like a three thanks for the input.

Godfather10 · Sep 27, 2025

Smokey_LaFleur said:
What power level do you have your light set to? I'm thinking some kind of ph or uptake issue. But, I use "living soil" and don't have a lot of experience using ferts throughout grows. Are these liquid fertilizers?

No powdered , and I make sure that they are totally dissolved

Calcium deficiency or light burn?

Calcium deficiency or light burn?

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Calcium deficiency or light burn?

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