Under a couple of our trees (one in front yard and one in back/different types of trees) our St. Augustine grass has turned yellow-green in the shape of the shadow of the tree folage. We are totally organic. We applied corn gluten in the early spring/late winter and then applied dry molasses and then Lady Bug. Our house faces south. Any ideas? Too much water? Not enough? Not enough light? We are puzzled. We have had a lot of rain and our grass is thick and healthy except for this. Thanks for your help.

Not enough light, too much moisture & use Horticultural or Whole Ground cornmeal for fungus type problems. Search the site for other fungus type solutions but I believe too much moisture is your main problem w/shade #2.

Thanks for the advice. I'll try the horticultural corn meal. The area gets sun, but from the sides of the trees not down through the leaves. One tree is a bald cypress and the other an ash.

My normally dark green St. Augustine now has light green blades throught the lawn. I assume it's because of all the rain, because nothing else has changed. It's that way in the sunny areas as well as the shady areas. Should I just wait until it dries out, or should ai use Texas T or some other fertilizer to help green it up?

Funny! I was about to post the same topic. Mine has been like this the past 4 years. My front yard is very shaded. But it gets early sun. My backyard is very open. The sun is blocked by the house early, but full sun rest of the day. Both my front and back look the same. Very yellow/green St. Aug. I have put down corn gluten/reg corn, green sand, molasses. Here is not the problem. IMO.

1) The extra heavy rain lately
2) To much Shade/Sun
3) The Organic Program- (i've herd this is the problem)

Here is what the prob is. IMO. *** Note*** My house had St. Aug when I bought it. I planted St. Aug 2 years ago in diffrent spots. All of it has changed to the yellow/green.


I think it is a nutritional problem. Not iron though. Maybe. Mag, Potassium, micro. I'm not really sure which one yet. I am going to get this weekend, a organic fert, with a lot of micros, I don't know which one yet. I will apply and let you know the results.
Brand/Rates/Price/ect...
Results....

I know this is not much help. But, if we try, and post results, we will all help each other.

Mine still sounds like an issue with lack of iron. There's no mottling, it like every 5th blade is a light green, through out the lawn, shade or sun.

Is the recommendation to just put a good overall organic fertilizer on or should I only treat it with an iron supplement?

Thanks Craig. I don't have heavy shade anywhere, it's pretty dappled. The yellowing is uniform through out the lawn, full sun or dappled shade. I probably won't do anything until this dang rain stops. I will probably start with a good overall organice fertilizer (Lady Bug or Texas Tee) and go from there. I'll keep you posted.

Regarding the text in green, you are kidding, right?
Corn gluten meal is the organic answer for those wishing to add nitrogen which, from what I understand, helps the grass to "green". (I like the Alliance Milling brand myself, but they quit making it for some frustrating reason, so if you can still find some, get it)! Photosynthesis is important as well. Not just important, but critical.
Our plants have not been receiving the sun they usually get because of the weather. I have a feeling this may be part of the "problem". A sprig of grass grew up into our garage and it was beige from lack of sun. Otherwise, it appeared to be quite healthy.

If you need to add iron, the best way to do so is to broadcast Texas greensand. Stay away from the bagged iron product that turns your sidewalks rusty. It contains arsenic.

I assume I could add greensand to the LadyBug brand organic fertilizer I just bought?

Either one is heavily genetically modified. I wonder what the effects the genetically modified products will have when being used for improving the soil... That is another post!

I posted the original question and have enjoyed everyone's input. I did try the green sand and the horticultural corn meal. We also did a sick tree treatment. We also applied the Lady Bug fertilizer for the 3rd time this year. The grass is still green and is very thick. Thanks for all the advise.

How do you control the invasive weeds?

I've just moved into my new home and the St. Augustine is dried out in spots (brown) and weeds are trying to take over. I live in humid Houston, and need to get the lawns greened up and healthy. The former owners used chemicals to treat and nourish everything.

Both front and backyards receive full day sun because I face North/South.

Thanks!

Brenda