From another question it looks like my avocado plants are deficient in iron. I'd like to explore and try natural/organic ways of supplementing iron. (I know organic is carbon and carbon compounds) So any ideas that involve supplementing iron through food/vegetable scraps or such would be awesome.
One "organic" option to provide iron is dried blood fertilizer, also called "blood meal". "Blood, fish, and bone" meal is also available.
Of course the blood came from slaughtered food animals, and there is no guarantee that they were farmed "organically" - whatever that means!
These products are also nitrogen-rich, and you need to take that into account if you are also using other fertilizers.
To get the iron without the nitrogen, you can use chelated iron. It's iron converted to a water soluble form for use in agriculture. Apparently seaweed fertilizer can also be high in iron.