Hey, welcome to the forum.
For any patio, you will have to dig down through the loose soil and get to stable ground. Some people will tell you to dig and pour a footer and fill it with rock. While this may be necessary in the North, in Texas, where the frost line is not so deep, You should be able to just remove the loose soil,(a foot deep around the edges?, less in the middle) lay a vapor barrier, and fill the middle with rock, tapering the rock down around the edges so that the concrete will go all of the way to the ground around the edges. This will contain the rock and keep some of the moisture out from under the floor, it also gives you a footer and more support around the edges. It would be good to float some rebar in these edges too. Loose Florida coast sand would require an entirely different approach. The soil conditions are definitely a consideration when pouring a concrete patio.
Tom in KY, where a patio will crack if it's not properly done.
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