I grow my trailing winter squash upwards, on trellises, in trenches 12" deep,12" wide filled with well rotted manure, leaving about an inch drop in the trench, I find this helps with the watering as I just lob a bucket of water in and it soaks immediately down to the roots along the trnch. Trenches are 4 feet long so I usually allow 2 plants per row.
My Pumpkins sprawl around under the sweetcorn, which I plant through weed supressing membrane. I dig a large hole, fill with manure, and plonk in my Pumpkin,with a pop bottle too! as has been said they are very thirsty and hungry plants! Hope this helps DP