Hello !!
I have a front yard we sodded last year with Raleigh St. Augustine ..
Its been doin Fabulous up until the last few weeks ..
The blades are still a healthy green but the base area has turned all brown ..

As I am in Grand Prairie we have had a huge amount of rain ..
Could that possibly be the cause ??
Ive read here the extra water may have have depleted the Iron ??

HEEEELP !!!!!

I apologize for being away for so long. I've taken a new job and have not had much chance to attend to my moderating. I like to get to these unanswered questions much faster than I'm getting to this one.

The heavy rains have not depleted the iron. Something different is happening that can be a little hard to understand but I'll try to explain it. To begin with, we have calcium based soils. When we grow anything in these soils we cause a surface layer of acids to build up which enables microbes and roots to survive. The more microbes and roots we have the more acidic the soil surface turns and we start getting better and better results with our gardening. As long as we're working in that top layer of the soil, everything is fine and improving. I need to add that the iron in the alkaline soil is chemically bound and is not available to the plants (or microbes) until the pH of the soil improves. But once we get the acidity up (pH down), then the iron becomes available. Okay, then what happens when we get a big rain? When the rains come and come for days and days the acidity of the surface of the soil is diluted with the overpowering alkalinity of the subsoil and can be completely neutralized and worse. What can happen is your soil returns to it's original alkaline state and you basically have to start over adjusting your pH. When the alkalinity returns, the iron in the soil attaches to the alkaline particles and is no longer available to the plants. That's when you get the chlorosis (yellowing) of the plant leaves a couple weeks following the rain.

Ironite does not work to resolve this problem. When you apply ironite to the alkaline soil, the iron is immediately bound up and becomes unavailable to the plants. The only material that seems to work is a product called green sand. Green sand is a mined chemical called glauconite. Glauconite is composed of lots of different minerals including some forms of iron; however, those forms of iron are similarly not available to the plants. But what glauconite does is that it provides a material for the alkaline particles to bind to which is preferred over the iron that became bound in the rain. So the glauconite essentially releases the iron back to the soil and the plants.

Okay, so far nothing I've said hear has anything to do with the brown base of your grass. Brown problems are different from yellowing problems. It has been several weeks since you wrote in so I'm going to ask you to update us with the situation more recently. I suspect you have large dead spots now. The culprit is either insects or disease. Due to the rains, disease seems to be favored, but you still could have insects. Can you write back and let us know what is happening?

_________________
David Hall
Moderator
Dirt Doctor Lawns Forum