Question
Kenneth,

I live in the New Orleans, LA area.  I recently (May 21st) sprayed a liquid weed and feed product on my St. Augustine grass.  The product packaging stated that it should not be applied while temps are over 85 degrees.  After consulting with my parents, who are fairly experienced gardeners, I was assured that it would not damage my lawn even though it was hotter than 85 degrees.

The product packaging also stated that there may be some chlorosis yellowing of the grass, but that this should be gone in 7-10 days.

Well, needless to say I'm concerned about the current state of my grass.  The grass began yellowing 4-5 days after application.  It has now been 16 days since application, and there are still very large patches of yellow grass that looks like it's on the verge of dying (if it's not already dead).  There are still several areas of healthy green grass, but I would say overall there is more yellow/damaged grass than green.

So I guess my question is what now?  Is this yellow grass likely to now die off?  Does the lawn have any chance to grow back if given time?  Is there anything I can do to help it recover?  Any help would be greatly appreciated.  Love the website!

Answer
the problem with weed and feed is that it becomes volatile in hot weather and can kill plants they were supposed to be safe for. the herbicides will kill broadleaf weed plants while not damaging grass (monocot) plants. But in hot temperatures, they may also kill grass.

It sounds to me like you got herbicide damage.

The best you can do is to water frequently, mow the lawn back to 2" and keep an eye on it.

Sorry, but only time will tell if this was a bad idea.