Desperately looking for advice. First grow, deficiency problems.

[Markyb]

Hi! My first grow was a smooth sail until flowering. No deficiencies whatsoever during veg, but soon after flowering the problems started and they are spreading fast.
Can this grow be saved?

Grow info
Strain: RQS Quick One
Soil: Biobizz LightMix + 30% perlite
Nutrients: Canna Terra Vega and Canna Terra Flores
Light: 100W LED
It is now day 48 since sprouting.

My water is pretty soft, only around 50ppm/0.1EC, but the Canna Terra nutrients do contain some amounts of Cal and Mag but I don't know if its enough for water this soft.
I have been watering by weight, I have been watering when the pot feels like it was filled with Styrofoam and it been around every 2 days.

I have been pretty stingy with the nutrients because I was really afraid I would burn my plant with too much nutrients.
This is the feed chart I have maintained based on how and when I have used the nutrients: (Please note the ratio is shown as mL/L in my chart and mL/10L in manufacturer and reseller charts)

And these are the manufacturer and resellers charts:

My plant looks like this at the moment. I guess the image shows the leaves to be much more yellow than they actually are. For some reason I have trouble getting a proper picture. But there definitely is yellowing. Some folks have suggested it has Potassium and Magnesium deficiency.
I have upped the bloom nutrient a little bit (I don't want to shock her). But I'm not sure if its enough. And I'm also really confused on how often should I use the nutrients.. Once a week? On every watering? every other watering?
I have also prepared a light CalMag mix for the next watering, my tap water being very soft and been stingy with the nutrients I thought I should add some magnesium for her. There is also probably some light stress also on the top leaves, she was stretching so fast that I had trouble keeping up with rising the light.

Any advice is appreciated.

 

[cosmox]

Hi, I think the best thing you can do is water and measure the EC of the water that comes out (to have a real idea of how much food there is in your substrate).

It doesn't seem like anything serious, you can just see some yellow leaves on the lower part... for me it's nothing to worry about.

You probably need to add some vegetative base (even if you're already in advanced flowering), but it's a decision I would make based on the EC values of your substrate.

 

[Markyb]

Hi, I think the best thing you can do is water and measure the EC of the water that comes out (to have a real idea of how much food there is in your substrate).

It doesn't seem like anything serious, you can just see some yellow leaves on the lower part... for me it's nothing to worry about.

You probably need to add some vegetative base (even if you're already in advanced flowering), but it's a decision I would make based on the EC values of your substrate.

Thank you! Unfortunately I did not purchase EC meter, I guess I have to get one soon. But I'm relieved to hear it does not look too serious.
Oh, and I forgot to mention I have been pH:ing the water (with or without nutrients) to 6.6 every time. And the runoff has also always been between 6.5 and 6.6.

 

[cosmox]

I understand, yes... I think an EC meter is an ideal tool for these types of questions, but if you don't have one, my advice is to add TerraVega, 15ml for two weeks... to what you're already putting in TerraFlora, especially to have some nitrogen available, which is also consumed during flowering...

 

[JP1]

These plants look fine. Maybe a little hungry. The bottom leaves look like that because they don't get any light. You can just pluck them off. Runoff EC isn't gonna tell you anything if you're growing in soil

 

[Markyb]

These plants look fine. Maybe a little hungry. The bottom leaves look like that because they don't get any light. You can just pluck them off. Runoff EC isn't gonna tell you anything if you're growing in soil

Thanks! Now that you mention this about runoff EC, I remember reading the same from somewhere that the single value wont give any info what's going but that the trend could be useful when taken after ever runoff?
But I guess EC meter is a good tool to get anyway, for prepping the feed/water?
Good to hear the situation is not so bad! I was just really scared for the sudden change in the shade of the plant.

 

[Markyb]

I understand, yes... I think an EC meter is an ideal tool for these types of questions, but if you don't have one, my advice is to add TerraVega, 15ml for two weeks... to what you're already putting in TerraFlora, especially to have some nitrogen available, which is also consumed during flowering...

Thanks! I will keep the Vega amount you suggested in the feed, I remember reading especially autos may get N deficiency during flower.

 

[JP1]

Thanks! Now that you mention this about runoff EC, I remember reading the same from somewhere that the single value wont give any info what's going but that the trend could be useful when taken after ever runoff?
But I guess EC meter is a good tool to get anyway, for prepping the feed/water?
Good to hear the situation is not so bad! I was just really scared for the sudden change in the shade of the plant.

Runoff EC is a tool for coco growing. Soil runoff EC is always gonna be crazy high since soil holds minerals. Input EC is good to know. You should be on strictly flowering nutes at this point

 

[cosmox]

Thanks! I will keep the Vega amount you suggested in the feed, I remember reading especially autos may get N deficiency during flower.

Photoperiodic and autoflowering plants can suffer from N deficiency during flowering, there is no exact feeding recipe that always works... each plant is in a different environment, with different humidity, temperature and light levels, so they "eat" differently. Yes, I would give it some vegetative food, not much... but I would give it some.

 

[Lil Dab]

I guess the image shows the leaves to be much more yellow than they actually are. For some reason I have trouble getting a proper picture.

It best to use normal 5k lighting for diagnosing pictures it makes them look like they are grow lights make them look different

And I'm also really confused on how often should I use the nutrients.. Once a week? On every watering? every other watering?

How often you feeding now every watering, every other? Plants look fine maybe little light in color but IMO your better off underfed then overfed but I agree with JP bloom nutrients should be used they have plenty of nitrogen in them.

h, and I forgot to mention I have been pH:ing the water (with or without nutrients) to 6.6 every time

Soil ph should be around 6.2-6.5 might little high but shouldn't matter that much in soil

I remember reading especially autos may get N deficiency during flower

Actually quite the opposite IMPE they get N tox easier