The iron sulfate in Iron-tone would work. Don’t over apply. Low fertilizer rating, good.
Blood meal in an organic fertilizer sounds ok, would be slower. High nitrogen, maybe not good.
I use seaweed emulsion… and the iron in Bioglod.
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@Bonsai_Bentley what’s the water pH in your part of S. Carolina? Are you conditioning? Alkaline water slows iron uptake… is it high in cadmium and cobalt? They displace iron .