Iron Chlorosis


Let’s talk about an issue Ive been seeing a lot of lately with all the heavy rains. A condition called Iron Chlorosis, where the grass blades start to become pale yellow to almost white in sever cases. It’s simply a lack of nutrients in the lawn, mainly iron, causing the pale appearance. Many people can confuse chlorosis with a Nitrogen deficiency. However a nitrogen deficiency will leave the blades a more solid yellow color rather than pale. But we will talk about that at a later time.


There are a few different reasons why a lawn can become chlorotic. The most common reason is over watering. Either from running the irrigation system too long, of from too heavy of a rainfall. The excess amount of water will cause the nutrients to wash out of the lawn. If this is the case, a fertilizer containing iron or a sprayable iron treatment can help correct this issue. Always be careful when applying iron products because they will stain non target areas. Check the irrigation system to make sure its not the cause or any treatment will be in vain.

Another common cause is high phosphorus levels in the soil. If the pH level of the soil is too high, it will cause a distortion in the nutrient uptake of the turf leading to this pale color. If this is the case applying a 21-0-0, which is Sulfate if Ammonia, will help balance the pH of the soil, and give the turn some extra nutrients. 5 pounds per 1,000 sq feet is the normal rate for this, but could require a few treatments to get the pH to drop where it needs to be. Make sure to test the pH between treatments to make sure you don’t send it too far the other direction. The pH level for St Augustine you should aim for is 6.5.


With this, and any other issues you have, I recommend seeking the help of a Lawn Care Professional. They will have the products and equipment to properly take care of any issues you may have. If you decide to do it yourself, always remember : THE LABEL IS THE LAW! Make sure to careful read the label of any product you use to make sure its the correct product, and that you apply is correctly. It is against the law to use products outside of the parameters stated on the label.