People need iron--and so do lawns.
Plants need iron to form chlorophyll, a necessary component for photosynthesis in plants.
If grass is not getting enough iron, it can result in patches of yellow lawn, a sign of the condition called "iron chlorosis." This causes the leaf of the grass to turn yellow (the veins of the leaf remain green). In severe cases, iron chlorosis causes the grass to turn brown and die.
Dr. Jerry B. Sartain, professor of turfgrass science at the University of Florida, explains in a Grounds Maintenance Magazine article that grass responds differently to a lack of iron depending on grass variety and the region of the country. Warm season grass is more sensitive to iron deficiencies than cold season grass. Warm season grasses prone to turning yellow from iron deficiency include:
- Centipede grass
- Bahia grass
- Bermuda grass
Root of Iron Deficiency in the Soil
If your yellow grass condition is due to iron deficiency, it doesn't necessarily mean a lack of enough iron in the soil. It may mean that the soil's pH is too high, or there is a high phosphate level in the soil. These two conditions inhibit the absorption of iron by the plant.
How to Cure Iron Chlorosis
Test the pH of your soil. If it is too high, correct it by adding sulphur, ammonium, or other acidifiers like aluminum sulphate. If your pH is normal, the soil may be too high in phosphorus, often the result of phosphorus-heavy fertilizers.
You can add an iron supplement in the form of ferrous sulphate, ferrous ammonium sulphate, or a chelated liquid or powder. Read the instructions carefully. Iron supplements can temporarily stain sidewalks and driveways red.
To see what iron chlorosis looks like, visit the Texas Cooperative Extension's Web site feature, Gardening with Skip.
