I have not grown Florida giants but I have grown watermelons before, plant asap in ground in full sun in fertile soil and prepare for huge plants so space is key.

Thank you. How much water do you normally give watermelon plants.... Unfortunately now I have 5 sprouted Florida giants and 4 crimson sweet that sprouted.

Plant 2-4 seedlings in a 12 inch diameter hill in a 10 to 12 foot square mulched basin and flood irrigation with hose as needed when you can't easily push a screwdriver into the earth.
Watermelon roots reach deep and far.