Perfect. Do I just buy something like this combination, dilute it in water and apply?

https://www.amazon.com/Ferrous-Sulfate-Heptahydrate-Greenway-Biotech/dp/B00KJL5ZL4

https://www.amazon.com/Ortho-Spray-Multi-Use-Hose-End-Sprayer/dp/B0071D0EZK