You can buy iron chelate powder at some nurseries but around here they don't all carry it. It's worth asking though. You can get iron chelate for plants on Amazon also, the smallest size would be best as you'll probably need less than a teaspoonful. I saw one iron chelate product on there in 8 oz. size for $9 just now on a quick look. If I didn't think it might be deemed a suspicious powder and get stopped at the border I'd send you enough for one plant in the mail!
For just a test the more easily obtainable drug store iron tablets might be the simplest solution for the individual plant.
