Question
I live on the Mississippi gulf coast and I have St augustine in my yard. In early spring i notice the dandelion and broadleaf as well as clover covering large areas in my yard so I went to the local co-op here and he suggested i uses some broadleaf killer for lawns. I bought a quart of 2,4-d by American brands and it said to use 3 oz per 3 gallons as I did. In a week with no rain my grass is now yellow and very blotchy. Can I fix this or should I just bite the bullet and order some sod. We did get about 4 inches of rain this past weekend will that help. thanks Shawn

Answer
NEVER use 2,4-D.  I don't care who makes it.  The stuff is outlawed in several states and it is awful.

Besides, there are newer, better ways to deal with this problem.  I am sorry your local Co-op people are not up on the latest technology.  They mean well.

Time to shape up.  Lesson one:  Mow your lawn right:

www.helium.com/items/981092-lawnmower-weapons-whacking-weedsmow

Note please the particular mowing height for St Augustinegrass.

Next, let's talk about water and St Augustine.

Would any of those Weeds on your Lawn happen to be Dollarweed?  Here's a picture:

www.cooperseeds.com/dollarweed.php3?cartid=

and here:

www.grreatideas.com/weed-id.html#Dollarweed

A few years ago, a researcher published a study, 'Impact of Cultural Factors on Weed Populations in St. Augustinegrass Turf.'

Now, when they talk about 'Cultural Factors', sir, they are not talking about whether the homeowner is Italian or Irish.  That 'Cultural Factors' has to do with things like how much you water it, how you mow it, etc.

So Univ. of Fla. planted some plots over in Broward County, Florida, with 'Dollarweed' ('Hydrocotyle umbellata' to botanists -- we Yankees know it as 'Pennywort') .  Then they plugged in Floratam St Augustinegrass.  For 3 years, they watered, mowed and fertilized in every combination of ways.  Then they counted the Dollarweeds.

Dollarweed had invaded 30 percent of the plots that were watered Daily.  One year, the Dollarweed was even stronger when they fertilized the Lawn.  But Dollarweed was only 2 percent of the plot when they waited for the St Augustinegrass to wilt before watering.

So the short answer to your question about 4 inches of rain, 'Will that help?', the answer is: No.  And the long answer continues:

While Dollarweed barely managed to survive the drought treatments, other Weeds had no trouble picking up the slack.  Researchers noted, 'The largest cover of other Weeds was under Severely Wilted irrigation,' that is, plots that wilted before they were watered again.  When they were fertilized, those same Weeds grew weak.  The shortest Lawn had the fewest Weeds -- other than Dollarweed.  'After 3 yr of cultural management, most plots were excessively weedy, and turfgrass quality for all cultural management-treatment combinations, in the absence of herbicides, was unacceptable.'

Dollarweed's need for H2O is SO acute in fact that it is called an 'Indicator Weed' -- a reliable sign your Grass is way too wet for its own good.

University of Florida's Dr Phil Busey calls this 'the most serious weed of St. Augustinegrass lawns in Florida'.  Thanks to the desert conditions in California, it is nowhere in sight on the West Coast. Do the math.

Dollarweed NEEDS water.

St Augustine is FAMOUS for its drought tolerance.

What would YOU do?

Now, you are having trouble with Dandelions (perennial weeds) and various other broadleafs.  I have to point out that Clover is not in truth a Weed -- unless it's Black Medic and LOOKS like Clover.

All Clover is not alike.  What you are calling 'Clover' may in fact be Black Medic, my friend.  Black Medic is an invasive weed, as undesirable as Crabgrass and Thistle.  It does NOTHING good for your Grass.

Here's how you can tell the difference:

Black Medic:

www.msuturfweeds.net/details/_/black_medic_29/

White Clover:

www.msuturfweeds.net/details/_/white_clover_28/
(note the pretty trefoil watermark on the leaves)

Yellow Wood Sorrel:
www.msuturfweeds.net/details/_/yellow_woodsorrel_30/

To the untrained eye, these all look like CLOVER.  But side by side, you see they can be distinguished.  They are as different as ketchup and mustard.

You can't do anything about the rain you're getting.  But it is so important to take good care of your Grass.  Agralawn has formulated a proprietary, organic weed killer that won't make you sick and may work very well.  St. Augustine Grass, Common Bermuda, Bahia, and Centipede lawns have been successfully tested for resistance.  

I am planning on applying it to my own Bluegrass and Bentgrass lawn in test patches this summer and I am hoping it is as effective as claimed.
 
Go to the Lawnrite website:

www.crabgrassalert.com/products4.html

Check out their herbicide.  If I didn't expect it to work, I would not refer it at this point - but I must mention it is still not know yet to me how good this stuff really is and I won't know until next spring.

I do think it is worth giving a shot.  Which is why I'm testing it.

There are spot weed killers on the market but I don't think they are practical, since you have a lot of weeds.  I don't know how it got this far, but if you can be patient, mow at the proper height, apply Corn Gluten for annual weeds, water and fertilize your Grass properly, and hand pull dandelions, I think you will see a dramatic improvement in your Lawn in a year's time.

I will shut up now.  Any questions?