yellowing St. Augustine

[Brian B]

Help! I have irregular yellow-green blotches in my otherwise healthy St. Augisting grass. And they're getting bigger. It starts off as a very bright green, then turns yellow-green. I know it's rained a lot, but there's good drainage there.

Is corn meal the best thing to do for this? Should I wait for the rain to stop before applying? I also thought I head Dr. Garrett say something about garlic?

[sandih]

Check under "Lawn Care" for some answers to previous posts about this problem.

[Dchall_San_Antonio]

Greensand at 40 pounds per 1,000 square feet is the solution, but go to lawn care and look around anyway. This phenomenon is the result of Texas calcareous soils. You can develop a few inches of acidic surface soil but when the rains come, it washes the acidity away. Without acid, the iron binds up with the calcium and leaves nothing for the plants. If you don't use greensand, you will not have dark green grass again until next spring, but you will have it again next spring. No amount of protein fertilizer will get you out of this problem.

[bgdug]

I had the same problem a few months ago. I had two spots that were about 10 sqft total. I just broadcast a few handfulls of horticultural cornmeal over the area and after about a month or so it was gone. Not sure if it was the cornmeal or the rain finally slowing down.

[Brian B]

Thanks for the help!

After looking closely, I determined it was iron deficiency, and I corrected it...and the lawn looks great now!

Thanks for all the ideas!

[sandih]

Brian, do share what you put on the lawn!

[Brian B]

I used a liquid iron chelate on the spots (I forget the brand) and put down a lot of greensand all over the yard. I think the liquid iron (I got it at Green Mamas) is supposed to eventually wash out after rain and watering, so the greensand should help keep iron in the spoil.

But, the yellowing was gone within about two days!

[sandih]

Great. Did you have to add lava sand to ease the distribution of the greensand? I'm about to do the same thing.

[Brian B]

I did add lava sand to the green sand. I got the green sand at the Lowes in Southlake because they keep it under a roof. Many other places keep it out in the open so when you get it home it's a bag of hard mud.

Since the rains and the humidity, there were still a lot of clods in it, but mixing in the lava sand really helped. And I know from previous experience, you can't have too much lava sand on your yard. I don't know about green sand (anu ideas out there?), but a lot of lava sand is okay.

I added the dry ingredients first, then I sprayed. I sprayed the iron chelate according to directions - and don't buy a lot unless you have a huge area - a little goes a l-o-n-g way! I don't think that the order makes any difference - but that's what I did.

Good luck!

[sandih]

I already checked with the Lowes by my house and they're out if it so I'll keep looking. Thanks for the information.

[Tricky Grama]

We stopped buying TX green sand over a yr ago b/c it was always in a hard wet clump. I'll check our Lowes to see if it's kept dry. Thanks for the tip.

Patty

[sandih]

I called the Lowes on Inwood and they assured me that their Greensand was dry. I drove the 12 miles only to find they were all wet and solid. DARN!

What is my other organic alternative to green up my lawn?

[sandih]

I found dry bags at NorthHaven gardens but they are double the price of Lowes.

[sandih]

Put in on the lawn on Friday and still waiting for it to green up....

[gsblake]

sandih wrote: Put in on the lawn on Friday and still waiting for it to green up....

How'd this turn out? After some testing on my own St. Augustine lawn over the course of this year I'm convinced greensand does nothing to green up my yard while applications of alfalfa meal and compost tea with liquid seaweed mixed yielded very green results.