This form of iron does not get locked up with other soil chemicals and is available to plants. They are sold under various trade names and in various formulations and can be applied to the foliage or to the soil. The recovery of plants from an iron-anemic condition can be amazingly fast. A sick, yellow plant sprayed with iron chelates can be a lush green in 48 hours. When sprayed on plants, chelated iron is absorbed by the leaves.
Some chelates are also mixed with water and poured over the soil and taken up through the roots.
When this is done, green color will return to treated plants within a week if iron is lacking. The other solution to iron deficiency problems is to treat the soil with an acidifying agent such as elemental sulfur or aluminum sulfate. These materials, when applied in the proper amounts, will correct the basic cause of iron deficiency which is soil alkalinity. Use sulfur at the rate of l pound per 100 square feet of area per application and do not use more than two to three applications per year. Sulfur must be washed into the soil immediately after application or it will severely burn grass or shallow plant roots.