HELP! Ambiguous symptoms

[DodgeViper]

Hello,


Please help me figure out what's going on.

I'm puzzled because my plants show apparently contradictory symptoms and I don't know what to do to correct it.

It seems like claw is a symptom of nitrogen toxicity:

https://imgur.com/lWO1IrF

At the same time, bottom leaves started turning yellow which is (?) a sign of nitrogen deficiency:

https://imgur.com/SkKBBii

https://imgur.com/HKwbtHb

It is surely too early for leaves to start turning yellow.

I noticed both symptoms about 10 days ago.

I also have the impression that growth slowed significantly or even literally stopped for a couple of days since then.

I'm a beginner, this is my second grow, first in coco coir.

My guideline is Grow 4-7+ oz with a 250W HPS – Step-By-Step Beginner Tutorial by Nebula Haze:

https://www.growweedeasy.com/250w-hps-beginner-tutorial

I use the nutrition schedule presented in the above-mentioned article with assumption that 1 tsp equals 5 ml.

My Setup:

• Grow tent 120x120x200 (4'x4'x6')
• 250W HPS in cool tube connected through the ducting to the exhaust fan.
• 4 Dinafem autoflowers: 3x Critical+ 2.0 Autoflowering and 1x AutoJack Herer
• 11 liter (3 gallons) plastic pots
• Coco coir with perlite (about 3:1 proportion)
• Exhaust fan 97 m^3/h
• Humidifier to adjust RH
• GHE trio FloraGrow, FloraBloom and FloraMicro, and Canna CALMaG Agent.

I use tap water without filtration. pH adjusted (GHE pH down) to cover the range from 5.5 to 6.5.
The values of temperature and RH are proper.
To keep things simple, I started in those 3-gallon containers without transplanting.
Germinated in rapid rooters.

I'm pretty sure that I overwatered in the beginning when plants were relatively small.
Symptoms of overwatering were green algae appearing on the top of the coco coir and of course springtails, which thrive in a moist medium.
Plants had infestation with springtails but since I sprayed cider vinegar on the coco coir (3 days ago), they disappeared.
I did some LST training (bending to the side), as you see on the picture.
Plants displayed on the pictures are 34th days old, counting day one as dropping seed to the water for 24hours.
Their height is about 30cm (one foot).

My questions

1. Is yellowing of leaves caused by some other factor than nitrogen deficiency ( overwatering, springtails, hardness of tap water)?

2. Although I stick to the nutrition schedule, there is clawing on some leaves meaning that there has been too much nitrogen supplied.
Is this because I use that Canna CalMag instead of GHE CALiMAGic? It has 6-0-0 NPK ratio and GHE CALiMAGIc has 1-0-0 NPK ratio.
Unfortunately, GHE CALiMAGic is unavailable in my location.
If so, maybe I should switch to Botanicare CAL-MAG (NPK 2-0-0)?

3. What those pale brown spots are sing of?
Is that calcium or manganese deficiency?

https://imgur.com/cVPE3CR

4. What would you upgrade in my setup?
For now, two things coming to my mind is adding an oscillating fan and switching to air pots/smart pots instead of using plastic pots.

5. Does Diatomaceous Earth has something to do with slow growth or yellowing?
I tried to beat springtails with DE before I used cider vinegar and I suppose I used too much of it.
In some tutorial about dealing with pests, there is written: "sprinkle DE on the top of soil/coco" but I supplied more than just a sprinkle.
Since it has alkaline pH (more than 7) maybe it changed pH at the roots?
By the way, those little bastards seem to be resistant to DE and to Neem oil.

6. Aren't my plants too small at this point (beginning of the flowering stage)?

Excuse me for linguistic mistakes, English is not my native language.

[Bengfan]

Take a loupe and look closely at the underside of your leaves. Looks like you may still have an insect problem, maybe thrips. Did you spray for bugs with or just prior to lights on? Could your plants be getting root bound? Look a little heavy on the nitrogen maybe as well. As far as upgrades, 7 gal. fabric pots are nice, an oscillating fan or two for sure, more light for that space. Good luck!

[DodgeViper]

I know for sure that it was springtails by the way they were moving. I sprayed for bugs with lights on. I don't know how to evaluate if root system became root bound. Next time for sure I will start with a smaller container like 1 gallon and then transplant to at least 5 gallons. But the first time I grew in those pots non-auto plants in soil and they became big and old enough for harvest, though they had a nutrient burn. This time I tried in the same container autos in coco coir and foliage doesn't look healthy at all and I start to doubt if I should continue this or to begin new grow.

[Jordann]

Alot more than nitrogen can cause leaves to claw do some comparison to these photos. Do you let the coco dry right out before you water? Are you using the fertilizer at full strength?

[Jordann]

Do you have good air circulation and plenty of holes in the pots. More than the pit came with, I make lots of holes not just in the bottom but from bottom to 3 inch up from bottom. You said you might add a fan, do you have one in the tent now?

[DodgeViper]

As I wrote earlier, I overwatered plants when they were seedlings/early veg. I use nutrients just as it is prescribed in the schedule publicized in Nebula's article about growing autoflowers in coco coir. I have only an exhaust fan that is removing hot air produced by HPS. No fan in the tent. I think roots at the bottom of the container were constantly wet throughout this grow.

[DodgeViper]

Today it became even worser. I had to take off several leaves. They look very fragile and some are dry and breakable. Just look at the pics.
Should I give up on this and try new grow? It doesn't look right.