Did you get any of those frosts/freezes last week. Seems like a lot of grass around here in se GA took a hit from the hard freeze.

We had a few chilly nights here in New Orleans, but not freezing. Maybe low 50s.

What is your watering schedule? How often and for how long do you water it?

What was the weed n feed product you used? St Augustine is sensitive to just about every herbicide.

I don't really have a watering schedule, we've never watered the lawns at any of the places we've lived here in New Orleans. I guess we typically get enough rain to handle the watering and St. Aug is supposed to be fairly drought resistant. That being said, I started setting the sprinkler out in the mornings every 2 days about 10-15 minutes the past week. I have no clue how much water that provides though.

The weed and feed product was by Vigoro. 20-0-0 I believe.

Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.

What is important about the wnf product is the herbicide used in it. Just because it says it is safe for southern lawns, does not always mean it is safe for St Augustine. Bermuda is a bullet proof southern lawn that can take all the herbicides EXCEPT the one designated for St Augustine. That would be the atrazine based herbicides.

Unfortunately, many times purple can be a sign of a nutrient deficiency.

Unfortunately, many times purple can be a sign of a nutrient deficiency.

Does that hold true in other plants? One of my tomato plants is purple underneath one of the leaves, I was wondering what that was all about.

I'm not an expert on individual plants and what might be just a natural color change for a specific species, but, for example, a P deficiency will often show up as a purple color on older leaves as the plant pulls P from them to supply P to new leaf growth.

Not being familiar with St. A., purple isn't natural is it?

That sounds about right, it's an older leaf and they haven't been getting much phosphorus. I'll dissolve some TSP and give them a feeding.

I don't know about St. A but crabgrass turns purple when it's about to die, either from cold or herbicide.

That weed and feed probably had 2-4-d in it. I would personally avoid that in SA, I think that is the consensus here.

Interesting thread...

Purple is very normal for Floratam and one other variety of St Augustine. It appears usually in the winter in the stolons and sometimes the blades, but yes, very normal.