if you need a quick fix chelated iron can be sprayed foliarly. the pelleted form for longer lasting methods doesn't work as quickly, though.
however, i really like and use 'dr. green' liquid, but it leaves an unsightly black mess on the leaves if sprayed. i haven't been able to find 'dr. green ' of late and have resorted to 'monterey dr. iron' in pellet form. (unfortunately, i threw away the last gallon of 'dr. green' so i don't know who the manufacturer is, and the nursery where i purchased it, is no longer open.☹️
there are a few liquid products out there, i don't know if they can be sprayed. but i am sure they can be mixed, and poured around the plants.
