Clawing and yellowing seedlings

[mimosa17]

What do you think the problem is with my seedlings?

They are in coco,
EC is around 900 and PH 6.0

 

[MickFoster]

They're starving.
What's your feeding schedule?
How old are the plants?

 

[bk78]

I’ve never had bark in my coco

 

[Phytoplankton]

That "Coco" should be much finer than that, you normally don't see chunks and chips, not even sure if it's all actually coco. My guess is that your problem(s) are twofold, I don't think that coco is draining well and is interfering with the root growth, as a result the damaged/stunted roots can't absorb enough nutrients.

 

[mimosa17]

@Phytoplankton @bk78 I am using a custom mix as medium, those barks are like sponges and comes with COGr
%20 fine coco
%50 Canna COGr https://www.canna-uk.com/cogr_boards
%20 Perlite
%10 sphagnum moss

Nutrition:
Terra Aquatica DryPart Grow (aka GH MaxiGrow)
Terra Aquatica Silicate
Terra Aquatica Fulvic

My tap water has 8.0PH and its soft EC 180
I always use Silicate to reduce PH and add some cal mag
When I put DryPart grow I was targeting EC 700

I guess I need to ramp up the EC a little.

 

[Go go n chill]

Do you have a nice light? I would transplant into something that resembles a finer coco and feed them with something over 1200 ppm but in small amounts right near the small root zones of those plants. They look hungry but it’s hard to feed them if they aren’t taking up any water

 

[hotrodharley]

@Phytoplankton @bk78 I am using a custom mix as medium, those barks are like sponges and comes with COGr
%20 fine coco
%50 Canna COGr https://www.canna-uk.com/cogr_boards
%20 Perlite
%10 sphagnum moss

Nutrition:
Terra Aquatica DryPart Grow (aka GH MaxiGrow)
Terra Aquatica Silicate
Terra Aquatica Fulvic

My tap water has 8.0PH and its soft EC 180
I always use Silicate to reduce PH and add some cal mag
When I put DryPart grow I was targeting EC 700

I guess I need to ramp up the EC a little.

You need straight coco to get results that you want. Bark sucks and it’s a bug magnet. That’s a mix of mess that you’re using.

 

[mimosa17]

Do you have a nice light? I would transplant into something that resembles a finer coco and feed them with something over 1200 ppm but in small amounts right near the small root zones of those plants. They look hungry but it’s hard to feed them if they aren’t taking up any water

Yes I have, I am using Samsung LM301B boards topped up %10 with 660nm
Actually things were going good around 400 PPFD until I have watched

There Dr. Bruce Bugbee says, you can shoot strong light to seedlings. When I ramp up to 700 PPFD.

They either didn't liked the brighter light or its because they are under light feeding schedule.

 

[mimosa17]

You need straight coco to get results that you want. Bark sucks and it’s a bug magnet. That’s a mix of mess that you’re using.

This is the first time I am growing in COGr which is having coco barks a you say. As structure its feeling like mixing mapito with coco.
But I did grows with fine coco and perlite... Back then I was using organic stuff and had a lot of thrips.
Eventually I decided to move away from organics because of bugs and hard to be precise.

For now I have increased the feeding and dropped the PPFD back to 400. I will update if they will be improved.

 

[Go go n chill]

This is the first time I am growing in COGr which is having coco barks a you say. As structure its feeling like mixing mapito with coco.
But I did grows with fine coco and perlite... Back then I was using organic stuff and had a lot of thrips.
Eventually I decided to move away from organics because of bugs and hard to be precise.

For now I have increased the feeding and dropped the PPFD back to 400. I will update if they will be improved.

Good luck bud

 

[Actinolite]

@Phytoplankton @bk78 I am using a custom mix as medium, those barks are like sponges and comes with COGr
%20 fine coco
%50 Canna COGr https://www.canna-uk.com/cogr_boards
%20 Perlite
%10 sphagnum moss

Nutrition:
Terra Aquatica DryPart Grow (aka GH MaxiGrow)
Terra Aquatica Silicate
Terra Aquatica Fulvic

My tap water has 8.0PH and its soft EC 180
I always use Silicate to reduce PH and add some cal mag
When I put DryPart grow I was targeting EC 700

I guess I need to ramp up the EC a little.

Are you actually checking the pH? Aquatica Silicate is "pH stabilized" so it should not be reducing your pH from 8 to what your plants are wanting. You also shouldn't even be giving your plants silica at this stage. An EC of 700 should be more than enough if the pH is actually anywhere near what the plants can even process nutrients at.

 

[mimosa17]

Are you actually checking the pH? Aquatica Silicate is "pH stabilized" so it should not be reducing your pH from 8 to what your plants are wanting. You also shouldn't even be giving your plants silica at this stage. An EC of 700 should be more than enough if the pH is actually anywhere near what the plants can even process nutrients at.

Yes, I am using PH strips.
My plain tap water is 8 PH. Adding silicate in very small quantity like 0.2g per liter drops it to 6 to 6.5 PH
This also same for Dry Part, when its added I see PH stabilized around 6.

Actually this is one of the reasons I like TA dry stuff, PH stops being a problem with them.

 

[Phytoplankton]

Not really a Coco Grow, more of a "Frankensoil". Did some reading on Canna CoGr, did you do all the rinsing and prepping of the coco, as recommended?

 

[mimosa17]

Not really a Coco Grow, more of a "Frankensoil". Did some reading on Canna CoGr, did you do all the rinsing and prepping of the coco, as recommended?

I didn't get what you mean by frankensoil

Yes, I also use coco bricks. I rinse them couple times and finally boiled water to kill if there are any eggs or so.

Then I flush pots couple time with PHed nutritional water.

 

[MickFoster]

You flushed out the calcium and magnesium.........never run plain water through coco.

 

[Drop That Sound]

You shouldn't let your fabric pots sit on the bottom of the tubs your using as catchment trays. You want them elevated up, so the old runoff water can completely drain away, without staying mixed in. That's my main concern looking at them..

 

[rmax]

Mine are doing the same and I'm in soil.

I'm now thinking my plants might be doing bad because the weather isn't hospitable for plants. They live in a cold basement and it's Winter outside now. Though it is 75 in the tent, humidity is 24%.

 

[mimosa17]

Today my seedlings looks much better.
I guess the issue was not increasing the feeding while boosting the lights...

They are gaining their green colour back.

 

[mimosa17]

You flushed out the calcium and magnesium.........never run plain water through coco.

Yes as in my post at last cycle I flush with nutritional water to put them back. But I don't think those blocks have cal mag in them in the first place

 

[mimosa17]

You shouldn't let your fabric pots sit on the bottom of the tubs your using as catchment trays. You want them elevated up, so the old runoff water can completely drain away, without staying mixed in. That's my main concern looking at them..

All the pots having clay pebbles layer at the bottom at least 1 inch. But I am always draining the cups couple hours after watering. Thanks for the advice