Watering Start now. Put out some straight sided cans, like empty cat food or tuna cans, and turn on your sprinklers. Time how long it takes to fill the cans. That is your target time for weekly watering. If you get runoff before you fill the cans, turn off the sprinklers immediately and let the water soak in for a half hour. Then continue the watering and start the clock again. Runoff does not count as watering. When you water, do it all at one time. Mowing Set your mower for the highest setting. Don't mow until the grass is tall enough to mow...unless of course you just like to walk around the yard making noise. Fertilizer I like organics, but not everyone does. If you use chemicals, wait until you have mowed the grass for the second time to apply. If you use organics you can start now and apply as often as your wallet can afford. Fertilize only the St Augustine and the runners as they creep over the yard. They should spread about 5 feet in the spring and another 5 feet in the fall. If you want it to go faster than that, you can strategically place some new pieces of grass in the yard and let them spread. New pieces of sod will need to be watered daily until they knit into the ground. I would not worry about preemergents, herbicides, or insecticides until you see grass growing. I'm concerned that the Bonide might slow down the new growth.

Well! Sorry to break it to you but it's been dead since about 2 weeks into that 5-week watering plan last year. it should have been watered about 5-10 times total since October and then only because it was new sod. Then from late November to now it should have been watered a total of 3 times. So, yes, it has been over watered. You may as well pick it all up and create a compost pile. There is a very strong chance that you have the disease which killed the grass instilled in your soil underneath. Once you get all the old sod out, I would scatter some compost over it at a rate of 1 cubic yard per 1,000 square feet. At the same time I would apply ordinary corn meal at a rate of 20 pounds per 1,000 square feet. Together the compost and corn meal should take care of the disease organisms in about 3 weeks. After that you should be free to put down fresh sod. Corn meal attracts a beneficial fungus which is predatory on the disease fungi. It takes 3 weeks to work but it works pretty well for me. I've used it every year since I found out about it in 2002. Before that I had dead spots year after year. Next time you put down sod, water it 3x per day but very lightly each time. Do that for 2 weeks or until the roots knit into the underlying soil. Once that starts to happen back off on the frequency and go up on the duration. Measure your sprinkler output by putting empty cat food or tuna cans around the yard. Time how long it takes to apply a full inch. That is your goal for ALL future watering. But you have to promise you will never water mature turf on a daily basis. You cannot go cold turkey straight to once per week, but get there gradually. At the most in SE FL you should be watering once per week during the hottest part of summer. When it cools into the 80s you should start backing off on the frequency to every 2 weeks. In the winter it should be once per month. I live in drought stricken Texas and this watering plan works. I've done some experiments with a house in George West, TX on the edge of the desert. I have parts of my lawn in the deep shade which have not been watered by me since October of 2011. 2012 was a very dry year and 2013 was not much better. I'm doing other things with the lawn as part of the experiment, but the point is, you don't need nearly as much water as you're giving it.

Hard to tell but it looks like there might be a different grass in there.

I've never seen a mower go to 5 inches. 4 should be fine. 5 would be nice as would 6 up to 9 inches. If you want to talk about tall St Augustine, I'm the guy to talk to. I have a lawn in George West, TX which has not been mowed since October of 2011. In most shady parts it is 32 inches high. Most of the rest is about 12 inches (full sun) but some is not up to 8 inches in all this time. Water conservation is the issue I was addressing by stopping mowing. The parts of the lawn that are up to 32 inches have not been watered in months except for our sparse rainfall. One part has not been watered once since Oct 2011. There is no thatch build up in any St Augustine no matter how high it gets UNLESS you water it every day and fertilize frequently with liquid fertilizers like Medina Hasta-Gro. That combination allows the entire grass plant to develop and survive on top of the soil - roots and all. If you follow our normal mantra of watering deeply once per (week or month) then you won't ever have thatch. Oh also feeding with dry fertilizer goes along with that. Yellow at the tip? When you mow it should not have a tip left? You should have an end that looks like someone sliced it very cleanly with scissors. If it looks raggedy at all, then you need to sharpen the mower. Here's a picture of my tall grass lawn. My dog is about 30 inches high at the tips of her ears. The grass had flopped over from being dry but it never showed any of the other signs of heat or drought stress. That picture was taken in April 2012. Note there is no sign of dormancy. I'm not sure why that was. Parts of the lawn did go dormant last winter but not the really tall grass.