Possible deficiency?

[Snzic]

Anyone have any idea what deficiency this may be? Boron? Calcium?

 

[GNick55]

over watered with heat stress?possibly too small containers? larger root mass equals stronger, resilient plant.

 

[Snzic]

The root mass and watering frequency/quantity is on point but it might be heat. I'll lower temps and see if it's a remedy thanks.

 

[Kepp89]

have you tested the ph of your soil? imo you have calmag def and potassium/sulfur def which are all in the same range of availability as far as ph of your soil goes.

i imagine the soil has it, but the roots cant use it.

unless thats rust due to poor airflow combined with heat

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[Snzic]

I'm on rockwool, the ph is 5.6 going in and 5.9 in runoff.

 

[Jimster]

The key might be the Ph swings. Usually, your outgoing Ph is slightly lower on the outflow because most nutrients are slightly acidic. Rockwool is fairly alkaline/high Ph, at least initially. It can vary considerably;y with the base component the rockwool is made from... rockwool made from limestone is more reactive than a typical slicate heavy mineral base. Perhaps the rockwool is a bit too high at the rootzone, causing the symptoms that you are seeing? If you have a high Ph and use Cal-Mag, you run the risk of further raising the Ph. I suspect a magnesium deficiency, but that can be a true deficiency or a high Ph lockout, since Mg is one of the first minerals to become less available at Ph reading much higher than 7. The problem could be right at the root zone, making it difficult to get a good idea of what is happening right at the root interface.
One way to check this would be to take a piece of the rockwool and soak it for a day, then check the Ph of the soak water to see if it raised from straight out of the tap/bottle. It's a bit of detective work, but might provide an answer. A foliar dose of Epsom Salts will also help remedy a magnesium deficiency, since it bypasses the roots and is absorbed directly.