How big is your giant pot? is it terracotta or plastic? terra cotta dries out fast.
in any case, garden soil in a pot is very heavy and although you want to give them lots of water, they also need drainage or the roots suffocate and rot.
garden soil in a pot is always a bad idea
you actually have a choice of a new product called raised bed mix. This soil is midway between potting media and garden soil in weight and water retention.
If your pot is big enough I'd say use the raised bed mix.
I'll caution against adding polyacrylamide hydrogels to retain water. some info that they can breakdown to carcinogens. also some folks question if they really make a difference or not. If you want to play, get water retention crystals based on cornstarch instead.
"giant pot" can be like when non-bird people think the have a "giant cage".
to get ideas about what is a big pot vs raised bed, watering/irrigation supplies, and general gardening supplies check out the catalog at
Garden Tools, Planters, Raised Garden Beds +More | Gardener's Supply
I'll be interested to see if you can do it outdoors, I always accepted that when my pea plants died it was because of the heat and nothing could be done.