Will it spread fine too? As you can imagine, it looks pretty ridiculous right now.

Botanbill, while I appreciate, sincerely, your input, if you live on sugar sand dunes and he/she doesn't, things could be different. It sounds like you and the OP might be relative neighbors, but I've been here a loooong time. FL is one of those places where you can't assume anything about the soil in different parts of the state. Tampa is one of those places where if you guess, you're probably wrong. While I expect sand, there are a bazillion lakes and ponds around there. Those don't form on pure sand, so there's a strong possibility he/she has something else. jmandawg, Do you get puddles when it rains? Do you still water even if you get rain? That does seem like an excessive watering frequency. If you can get your grass roots retrained to grow deeper in the soil, I strongly suspect you can restrict your watering to once a week or even less often. But if you're on sugar sand, then botanicalbill is going to have more to say about it. When I backfilled my back yard I used what amounts to sugar sand. It's 8 inches deep at the deepest, which I realize your soil is probably 80 feet deep, but still - it's sand for the entire grass root zone. That sand grows the best grass I have. After 12 years of organics the sand is black when you look at it, but when you put it in a jar of water, all the white sand sinks immediately to the bottom and all the black organic stuff floats to the top. That grass gets watered once every other week unless it rains. So far this year it's only been watered by me twice. We got some heavy rains and it really hasn't needed more. jmandawg again, generally the world gets by watering deeply and infrequently. Generally that means watering one inch of water, all at one time, and doing it once a week when temps are in the 90s. Other factors to consider are soil type, soil depth, grass type, grass height (yours should be mowed at the mower's highest setting), shade, clouds, wind, humidity, organic content of the soil, and some others. After taking all this into consideration, there are only a few places where the general advice would differ. One of those places is the area from Green River, Utah south to the Mexican border and west to Indio, CA and east to Junction, TX. That area is different because the soil is often gravelly. The sand is coarse and really does not hold any water. If Florida is another location where the general guidance does not apply, I have not heard about it. But I am certainly willing to listen to actual experience of people who have tried to grow deep roots and still required frequent watering. I'm still interested in the soil conditions for jmandawg.

Exactly right. You can encourage St Aug to take over by mowing at the highest setting and skipping a week or two now and then. Water deeply every week in the summer. It will spread best when the temps are in the 70s and low 80s. It should creep 10 to 15 feet per year. Here are my most recent example pictures. This picture shows almost no St Augustine. Most of the turf is bermuda, prairie, crabgrass, and some horse herb. If you look carefully the St Aug is between the pot and the concrete. There is also some underneath the faucet. That was summer of 2014. This is the same area with the pic taken last week. Everything that is lime green is St Aug (no fertilizer yet this year). The gray-green is prairie grasses. Knowing that I wanted to keep the St Aug I only watered the small areas where it was and let the other grasses suffer. When I saw a St Aug stolon creeping out into the other grasses, I watered that runner. If you have common bermuda, I would let the St Aug take over. If you have hybrid bermuda, then you have a decision to make. If you want to keep the bermuda, mow it low 2x per week and stop watering. After a month with no water, the St Aug will begin to die out. As long as it has a golden cast to it, it is still viable, so be sure it is dead before you resume watering. The dormant bermuda will come back fine and fill in where the St Aug was.

St Aug should grow fine in Altadena even with your water restrictions...maybe. What are the exact restrictions you're under? Here's the proper care guidelines for St Augustine. Water deeply and infrequently. More on that below. Mow at the mower's highest setting every week or 2 (or 3 in the shade). There's no reason to ever mow St Aug at a lower setting. Fertilize with chemical fert on Memorial Day, Labor Day, and Thanksgiving. If you want to use organic fertilizer, you can use the same schedule and add Washington's birthday and 4th of July. 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. Watering restrictions in the San Antonio area are fairly enlightened. We can water for a certain 7 hours one day a week. When it gets worse it changes to every 2 weeks. When it kicks into high gear, the secret to keeping St Aug alive is to stop mowing completely until it rains again. Tall St Augustine can go for months without watering. Really tall St Aug (30 inches) can go for years without watering assuming you do get some rain once every few months. Give us your watering restrictions and we should be able to come up with a way to keep the St Aug. With your relatively cool summer temps the watering guide above is quite different from what the average SoCalian is used to. I cannot stress how important it is to get the concept of deep and infrequent into your program. If you were trying to do it by watering daily, that is exactly the worst thing you could do. To answer your question, simply seeding Princess 77 and mowing low will, in the long run, kill off the St Aug. Once the Princess is fully established, then stop watering altogether for a complete summer and the St Aug should die out, unless it rains. Princess should have been seeded back in July when the soil was as warm as it would ever get in Altadena. I'm not sure you could do that now. TIF 419 sod would be fine now. I'm a little concerned about growing any bermuda in the areas you are calling shady. Bermuda must have 6 hours of direct sunlight to really thrive.