I'm getting lots of calls and emails lately about the overt "yellow" grass in St. Augustine yards. It's the kind of yellowing that some call a chartreuse color. Or the kind of green that might look like a faded out green. Sound familiar?

It could be a number of things causing this malady, but likely just one of two problems in particular. It's either Iron Chlorosis or Nutrient Lock-Up. Now, it could be the start of something more dreaded - namely, St. Augustine Decline. But, more times than not, it is the previously mentioned possibilities. Also, you may notice that this discoloration is under tree canopies, especially pine trees and crape myrtles.

So, here's what I've been recommending to folks with this "yellowing-chartreuse-pale-green" looking grass. First, approach it as if it's Iron Chlorosis, or a need for an Iron and Soil Acidifier. Put down any Iron/Acid combo you can find, and water it in. After two weeks, if you don't see a significant greening up, then assume you have a nutrient lock-up.

Products you've heard me recommend for Iron treatments:

• Hi Yield Iron Plus
• Ironite
• Iron Safe - from Lillie Miller
• Or Any liquid Iron/Soil Acidifier
  
  You can do a number of treatments for the nutrient lock-up as well. When I have nutrient lock-ups, the easiest thing to do is apply a Soil Activator/Microbial Treatment to the afflicted areas. Hopefully, if there's a phosphorous lock-up going on, it will help release the right nutrients up to the grass.
  
  Products you've heard me recommend for such treatments:
  
  
• Medina Soil Activator
• Medina Plus
• Greensense Mircobial Treatment
• Or Any Liquid Soil Activator Product
  
  If cost is no object, it is a good bet to do the Iron treatment and the Soil Activator Treatment together (well, at least one right after the other). I prefer this method - Iron first, Soil Activator second - both on the same day) because I don't want to have to wait around to judge results.
  
  So, what if neither one of these treatments works? Yes, it could be the dreaded St. Augustine Decline -- SAD. And frankly there is no cure for that. There are some fungicides that work a little bit on abating SAD, but none are effective at complete control. If you would like to learn more about SAD, click to here...
  
  http://aggie-horticulture.tamu.edu/