My seedlings are yellowing once again - Why am I cursed with this?

[Acid]

Hey guys,

It's been 7 days since my last post about this (probably) magnesium problem, so a little update for now - Nothing has changed. Generally, my plants are thriving. No nutrient burn, nothing. They are growing nicely. But sadly, this symptom is still appearing, now on all 4 plants. It spreads from the bottom to top, light leaf material between the veins of each leaf. It doesn't seem to be too dangerous, but it is an obvious sign that something is just off. The two which had this problem early on, are the most severe. The other two are showing mild signs here and there.

I contacted Canna & they recommended to cut my RO water with tapwater, as little as 25% is absolutely fine, just so I can get bicarbonates back into the RO water to stabilize PH, which calmag itself can't do. This will ensure a very stable PH in the long run, I think someone here even recommended doing that. So that's what I've been doing for a while now, but sadly it's all still happening. I also supplied epsom salts in the feeding water for a few days now, but it doesn't seem to help too. I think it was around 1 gram per 1L of water.

These plants are fed as follows AFTER I had this symptom appearing:

25% tap + 75% RO water. Tapwater adds 80PPM / 0.16EC of minerals, I then add my Calmag until I hit 225PPM / 0.45EC. Then epsom salts at around 1g/L. Afterwards the usual nutrient schedule of A+B until I'm at 800PPM / 1.6EC, which the plants seem to enjoy as there's absolutely no burns visible, it keeps being this magnesium-deficient symptom, and it doesn't seem to stop at all. It started happening with just RO water + calmag + a/b, it still happened with foliars, kept happening with tapwater + ro + calmag + a/b, and it's still happening with even epsom salts added into the feeding water.

I don't want to change too many things, I just wanna get to the core of this magnesium-problem I have, so I will stop experimenting for now and get back to you guys before I f something up again.

Take a look at the current state of my plants, these are the two most problematic ones:

And these are the two less problematic ones:

 

[SmokinRasta]

I contacted Canna

They offer a great customer service, don't they? - That's why I love and trust them!

Do you use the Epson salt for your Mg problem? I used Canna MONO Mg since I talked to them and it feels like working better for me. Maybe you should give it a try

 

[bluter]

use a proper ph adjust to set ph. mixing RO with tap, using lemon juice etc is a short term solution best suited to an emergency if no ph adjust is available. it won't remain stable long without the ph adjust.

run a proper calmag or mag supplement alone to correct the mag issue.

 

[Wastei]

I think you need to cycle the medium better running salts with your approach. Without any runoff and cycling of the medium the only way to balance it and not create salt buildup is to feed borderline low.

This approach is very hard to keep stable for any longer periods of time. By only wicking and feeding the medium from the bottom you will create an uneven root zone with higher nutrient concentrations and moisture in the bottom of the pots and stagnant water and low moisture and nutrient concentrations at the top.

For better performance runnings soilless and salts you should aim for a homogenous medium at all times meaning you have the same water and nutrient concentrations throughout the medium and pots. This makes the roots completely fill the root zone for maximum water and nutrient uptake. Bigger roots gives you the possibility for higher rates of growth and yield.

Maybe you should water through the pots a couple of times a week? I also see algae on the top of the pots that will affect growth and access to oxygen. I use regular bleach at recommendations in my signature to keep roots, pots and feed lines clean from algae growth.

What is the EC/ppm of your base water? I see very little reason to run RO in soilless if your base water stay below 0.4 EC.

Hope any of that helps!

Cheers!