PH Level - Knowledgebase Question

Bainbridge, Ge
Question by southga05
March 23, 2010
I recently did a soil test on my lawn. I have centipede grass.I live in the South(GA) and I recently used the Scotts Max Fert about 2wks ago. My PH level is 6.5 Average. Half the lawn is at 7(greener) while the other half is at 6(not as green). I researched that centipede should be around 5 or so. How much Ironite (40lb bag) do I need to use and how often should I use to get the right PH?

Answer from NGA
March 23, 2010


Because centipede lawns are naturally light green, there is a tendency to over fertilize them in an attempt to get a darker color. Extremely yellow centipede lawns could be caused by chinch bugs, or an iron deficiency in the soil. Centipedegrass thrives on moderately acid soils, pH 5 to 6. Above pH 7.0 iron becomes a limiting factor and supplemental applications of iron may be required. You can tell if your lawn needs iron by closely examining the blades. You'll see dark green veins and pale yellow tissue between the veins. Ironite will green up your lawn temporaritly, but won't fix the underlying cause. Although Centipede can be sensitive about pH, it is not a problem that you would notice unless the pH was higher than 7.5. At this range, the grass becomes so starved that it turns a lovely shade of yellow green.

Fixing the soil pH is never easy. Fixing soil pH in established turfgrass is even harder. And if you have a poor-soil problem, you won't fix it at all by adjusting the soil pH. To lower your soil's pH, use lime or gypsum. Regardless of what you are adding to the soil, use a lawn spreader to apply the material evenly. Liming your lawn will lower the pH but it can take several months to see any changes. You'll want to continue testing each year and adding lime if it's indicated by your soil test.

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