Question
so, i moved into my new house. i waited until the st augustine sod began to root before fertilizing. and yes, i picked up a bag of scott's. it's been about 2 weeks. i water the lawn approx 2-3 times per week for 10 minutes a section.

i noticed tonight that the tips are turning yellow. i couldn't believe my eyes. i am truly pissed off. i read another answer that you wrote for someone else and it stated something about good/bad fungi. do i need to stop watering the lawn? only my front lawn is doing this(my back does not receive as much attention).

help! how do i fix this?

Answer
Fungi MIGHT be your problem -- if you're lucky.  If you over-fertilized, you're less lucky.  If you used the wrong Scotts, you're in trouble.

Scotts 'Turfbuilder' is the cause of many problems for gardeners here at AllExperts Gardening/Lawns.  This is a HIGHLY concentrated chemical.  Using too much causes bad, bad burns.  May as well bring out the Sulfuric Acid.  Which explains why the Scotts Company is only too pleased to send you back your money when its Turfbuilder wipes out American lawns from here to there.  Their 'Turfbuilder with Iron' is just as bad, with the silly 'Iron' addition to the name as though you were adding vitamins to your Lawn.  It's just as toxic, just as concentrated, just as expensive.

Hard to believe, isn't it?

Green Grass one day.  Brownout the next.

Scotts has a standard remedy for this mistake: Water your Lawn to death.  If there is any trace of life there, pouring H2O over it will dilute the Turfbuilder and tilt the odds ever so slightly in your favor that your grass will survive.

If, however, the Lawn is beyond all hope, you have no other choice except to re-seed.  I would like to know, dear, if you fertilized the front AND the back both, or if you only WATERED them differently.  Please clarify.

Meantime, let's consider the possibility you have a Lawn Fungus.  I am not so sure this is the case, and I'll tell you why.

Fungus is one of those things that has to have constant moisture for long periods of time.  People with new Lawns often water daily, sometimes twice a day.  These people have automatic sprinklers.  They're affluent.  They don't deal with Grass.  They pay other people to do that.  But they have this sprinkler system, and they figure it's like running the dishwasher.  So they run it constantly.  Which is very nice if you're a Fungus.

But you did not do that, did you?  You 'water the Lawn approx. 2-3 times per week for 10 minutes a section'.  That's not perfect.  But it's not like the Lawn didn't dry out at all... or is it?  Was it raining in between those sessions you had with your new Sod?

Regardless, if you decided to 'fertilize' your Sod, I wish you had asked me first.  No Soil test?  Tsk, tsk.  Fertilizing at best will make your Lawn a beautiful place for target practice by your neighborhood Fungus colonies.  There's nothing like an over-Nitrogenated Lawn to bring out the Fungus amongus.  'Yellow' can be a symptom.  But there are others, and they usually get worse.  How's it looking today?

While we're on the subject, I recommend you pick up the article on Lawn chlorosis, 'Grass Yellowing: Save Your Greenbacks' posted by the North Florida Research and Education Center:
nfrec.ifas.ufl.edu/Newsletters/Archive2005/Newsletter_05_09_05.pdf#search='zoysia%20symptoms%20iron'

Then go out and subscribe to Rodale's Organic Gardening.  Start a compost pile with the kids.  Promise your liver you will never put it through another exhausting cleaning of your pesticide-laced blood again.  And water like crazy.  Maybe you can save some blades of Grass.

Lose the fertilizer.  Top-dress with Compost and Manure.  Convert to Organic.  You'll live longer.  So will your Grass.  RSVP