Nutrient deficiency

Howdy folks

I've been growing for about 4 years and this place has helped me solve a number of problems and issues I've run into during that time. But I'm at a loss on this one. I would be grateful for any input or advise.

The plant in question is a cross between Hash Passion and Gorilla glue #4. At first I thought it was a magnesium deficiency so I doubled up on the magnesium but it's been 8 weeks and it just seems to be getting worse as time goes on.

I've got 2 of the HPxGG#4, 1 in a 3 gallon pot and 1 in a 3 quart pot. Also have 2 GG#4, 1 in 3 gal and 1 in 3 qt.

Here's the growing stats:
3x3 tent indoors
Spider Farmer SF-2000 LED light
Large plant is in a 3 gallon pot, small plant in 3 quart pot
Growing in soil
Watering when the soil is dry about 1 inch below the surface
Tap water
PH 6-6.5
Nutrients are used in every watering
(This routine has worked very well on my last six grows except this one)

Nutrients are:
Jacks Hydroponics 5-12-26, 3 grams/gal
Jacks Calcium Nitrate 15-0-0, 2 grams/gal
Magnesium Sulfate 1 gram/gal (actually using 2 grams/gal)

This is my first grow using the Spider Farmer light and I'm very happy with how the other 3 plants are doing.

Here's a few photos:
The first shows HPxGG4# on the Left and GG#4 on the Right, 3 Gal pots.
Second is a closer view of HPxGG#4, 3 Gal pot.
Third is HPxGG#4 in a 3 Qt pot and it seems ok for the most part.

Forgot the photos

Forgot the photos

Looks like a pretty classic magnesium deficiency.

I suspect if you use less Jacks Hydroponics 5-12-26 things may get better.

Reason: The last number 26 indicates the Potassium(K) level. Coir has lots of K and it's why people use Cal/Mag with it.

Too much K can hinder the absorption of calcium and magnesium.

Click to expand...

https://www.cannagardening.com/interactions_between_nutrients

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Thanks folks.


I went back over my notes and think I figured out part of the problem. I was running short on funds when I started this run and reused the same potting soil from my last grow. Perhaps I am missing some of the micro nutes. This run only has a couple of weeks left and the plant in question was ready to harvest. No more recycling soil for me!

I think the bottle nutrients would supply all the micronutrients you need they are just not available. Using old soil may have raised the pH too high from using tap on the last grow and this one too.
Your tap water may be raising the pH and locking out the micro nutrients. I like to use a lower pH water "5.5 to 5.8 pH". If you could use RO water you would have better control of the pH.
Tap water that's above 6 will hold a lot of calcium, silica, potassium, magnesium, and bicarbonates which will block the receptor sites for the micronutrients locking micro's out.