Bermuda will not grow well in shady areas under trees but will probably grow everywhere else. Getting it to germinate will require continuous moisture for about a week and frequent watering to keep it going after that until it is established. In your sandy soil it might be tough to keep it moist the first week. The seeds do not like drying out at all during that period. If you have a season where it rains almost everyday for a few weeks and temp is in the 70s or 80s then you might want to plant then. Bermuda loves nitrogen fertilizer.

Because of everything rdaystrom said, I think bringing in new bermuda seed will be an uphill battle.

Forget about changing your pH. When you get a pH above 7, that indicates lime. The sand you are dealing with is calcium carbonate from the shells of bazillions of sea shells crushed over the eons by parrot fish in the area. When you apply sulfur, the calcium will dissolve according to how much sulfur you apply. If you dissolve it all, then you will have a hole where your island once was. You need to think in terms of adapting your gardening to the situation including soil, pH, climate, wind, temperatures, etc.

The good news is the grass spurs is the weakest plant out there. Once anything is growing, the sand spurs go away.

Now for the interesting part. You should get a prize for introducing a new weed to GardenWeb. At least over the past 10 years, nobody in this forum has asked about Egyptian grass...until now. Here is your picture of it...
{{gwi:121096}}

Since you already have that little piece of work, you would be best to just use it. It is a difficult weed to eradicate in good circumstances. If there is any good news, the seed is full of protein. If you let the grass go to seed and then mow it off, you might not ever need to fertilize. Protein is the key ingredient in modern organic fertilizers, so you have a ready source of it. Egyptian grass likes to grow in low spots in dense soils. If you can alter your soil profile to drain rain water away from where the Egyptian grass is, you might thin it out for awhile.

Here is some good news. You have many starts of St Augustine grass. It is the very coarse bladed grass in this picture...
{{gwi:121097}}

It must be watered regularly to thrive, but it will thrive in your high pH sand. It loves salt, too. I've seen St Augustine growing out into the sea. But your problem is keeping it moist. Many grasses will go dormant when they dry out. St Augustine has no dormancy for dryness. It goes straight to dead. You should find it trivially easy to grow if you have any shade anywhere...and you can make enough water. You might just have to take that during rainy years. As long as you have any alive, you can replenish the entire island.

In that same picture, the fine bladed grass does look like zoysia. Does it get seed heads? Zoysia might work for you. It does go dormant but once it does, it often does not come back at all in the same season.

This stuff below is a problem. It is not crabgrass.
{{gwi:121098}}

It is dallisgrass or a variety of other paspalums. Then again, it might be the lone survivor on your island. It can be killed, but it is not easy. Fortunately it is easy to dig or pull in your sandy soil.

If you want to save your back, raise your cinderblock barbecue up so you can stand to cook.

Sorry for getting back so late over here, but for some reason I do not get notification.

Anyhow. Thanks for the usefull info Dchall.

The problem is the expensive water. I have an underground sprinkler that is fed with RO water out the well.
The pure well water is just to brackish from time to time so I collect it in a 2000 gall tank by RO.

Thats why I wanted to go for Bermuda. It does not die if things get dry. (or saltspray because of hurricanes). Just dormant.

Are you sure it is St-augustine? I heard people say that it is Zoisya. (the bigger leaves)
I planted my entire yard with it 10 years ago (with spouts) but as you said.. it dies after drought.

Egyptian grass .. why is that weed? Its green? haha. If I would have that in the entire yard I would be more than happy :P

On the pic you post, with the st augustine, you see a very short,dense grass that grows very good on the Island, but is just dont like the fine texture. You can see every mole in the yard.
Its like walking on spikes with bare feet. It kills weed though cause nothing comes through. What type grass is that? You mentioned Zoysia but hmm.. i thought the bigger leave in the picture was Zoysia.

Hahaha.. the bbq is indeed to low, but thats how things go on the Island. Robinson style ;) But will build a new one next year. I even made a drawing for it.

This post was edited by ItsJorgen on Sun, Dec 8, 13 at 10:42

Fairly certain it is St Aug. The blunt tipped blades are a give-away.

Wish I could help you identify the spiky grass in the St Aug picture. It seems to grow low to the ground. St Aug will usually choke out low growing grasses if it gets dense and tall enough. But that won't happen without water.

Okay thanks.:) I hope to get back on here in a few month with some results. I decided to go for the Bermuda seeds and see if it wil germinate.

Dchal, look at these pictures at the moment. I think the St Augustine is doing well.
This is because of the rainfall .. i realy need to get my sprinkler back on line for the dry periods and do a fertilizer job.

And an other one

I have an area in my back yard where the St Aug died a few years ago. Bermuda filled in nicely, but I really want St Aug back there. This year I got the St Aug to refill by use of careful watering and fertilizing. St Aug will smother out bermuda if you let the St Aug grow up tall enough. But the bermuda will come back when the St Aug dies out from water stress.

Here is a picture of my lawn in George West, TX.

{{gwi:94032}}

My dog is a small chow chow, so you can see the grass is pretty tall. St Aug seems to grow up to 32 inches before it stops growing. This grass was in full shade under a tree with a canopy about 10 feet off the ground. I took that picture because that part of the lawn had not received anything but rainfall for the previous 9 months. It started off mowed to 3 inches in Oct 2011 and grew up to that height 9 months later. GW, TX is at the edge of the desert, and 2012 was a drought year, so it's not that much different from your island. Only real difference was being in full shade. That really helped because the grass I was standing in to take the picture was only 6 inches tall. I had been watering it weekly to try to get it growing, but out in the full sun in that heat it was not making much progress. The point is if you can get your St Aug up tall (at least 9 inches) it will live a lot longer on less and less water. I also had another 1,000 square feet of St Aug come in this year under a different tree. That came in like gangbusters before I knew it. I mow this lawn "down" to 16 inches with a string trimmer to comply with local regulations. Grass higher than 18 inches becomes a nuisance of some kind. In my experience with this tall grass since 2011 is that it is not a haven for vermin, snakes, or mosquitoes as the community seems to think.

My lot is an acre and not really next to anyone, so again, my lot is more like yours than the typical subdivision home on 1/4 acre. Stop mowing your grass and it should do better for you.

Wow .. that looks nice.

Seems like good advice. I really thought that 'mowing=growing' but keeping moist in I should let it grow higher. Hmm... Never thought about that. The thing is I actually never seen this stAUg higher than in my pictures haha. But then again I am not around all year. I will make a list for my care taker what to do or not.

Dchall. One other question about seeding. Does grass reacts just like other things in nature seasons?
I mean.. in cold countries leaves fall off trees in fall, and all comes back in spring. And you seed in spring/summer.
Does this work the same for areas that do not have real difference in seasons? I mean.. does grass stops growing in fall/winter on the islands?? Or does this not matter. Can you seed anytime as long as temps are over 70-80?
Like I told you I live in the Netherlands so I never looked into this before and/or did any study on this before.

Possibility here, if you have a bunch of old planting containers 1 quart or larger, start seeding in as many as you can with the native sand (or use some other container) and you can focus the water on those containers. Let them grow in those until you have containers full of grass. Then transplant them where you have sprinklers. Might actually start spreading as bermuda does. It might be worth a try so you don't have to use so much water over a huge area to start seeds.

@bermudakid

yea, that might work too, but to fill 40k of yard would take a while. But I might do that next to the normal seeding.

For sure I am going to concentrate on a small area to seed that I can maintain. An go on from there

Thanks for the tip and happy new year :)

Paspalum would also be a good choice. To late but maybe in the future. You can even water it with brackish water without problems. You do need fresh water to get it established but after that brackish water is fine.

Neilaz
Not to late yet. I did not buy seed yet. I am still working with the St. Augustine, but I know this dies after extreme drought. ANd i am looking for a similar type grass in apperance that can handle drought and heat and enviroment.
Bermuda seemed the good choice but I am not the expert :)