I agree and use iron.

Chelated iron is expensive and not necessary if the soil/water pH is under 7.5. Likewise, I would not add epsom salt (Magnesium Sulfate) unless you see definite signs of Mg deficiency. Having said that, I do sprinkle a little Magnesium sulfate (the agricultural variety, not epsom salt) on my garden Meyers whenever I apply it to my roses.

John if I used Chelated iron, I would not add it to the soil. I would use it as a foliar spray.

Silica,

That may work; but a few thousand commercial growers in the Rio Grande Valley would disagree with you.

Geeeees I've had people disagree with me before but never a few thousand Texans at once.

John and Silica have you two ever met??? :)

In the Rio Grande Valley soils are typically pH 7.5 or more and the water from the Colorado River in the vicinity of 8.0. For that they have to use chelated iron no matter what the cost. They apply it with the fertilizer in the ground. Could be a different game for container citrus; but I don't know why you would have container trees with 7.5 pH soil, or use 8.0 pH water.

Cincinnati, OH soil 7.8 Water 7.8

Johnmerr is right, to the extent I understand the chemistry. Chelated iron is usually not necessary if the soil ph is near neutral or acidic. Normal soil chemistry produces enough chelated iron if iron is at all available in the soil in any form. At higher ph iron becomes dramatically unavailable.

There are several kinds of chelated iron formulations. The most common one is EDTA type and only works for neutral to acidic soil. HEDTA only works for acidic soil. DPTA works for slightly alkaline soils. The most expensive variety is EDDHA and is the only one that works with high soil Ph.

Foliar application may be helpful in a pinch and for container plants in small scale. At least soil Ph will be less of a concern as long as the water ph is OK. But a soil application will be far more efficient.