Growing ginger plants
Thank you for your question. Do you mean 'can you plant ginger in the same container as Elephant ears'? Or do you mean in the garden, in native soil? Not knowing which you mean, the best I can share are their relative growing environments:
Ginger is grown from a rhizome that is 'buried' under the top of the soil, from 2 to 4 inches deep, and 6 to 8 inches apart. It will sprout, and you'll dig up the rhizome after 6 to 8 months to use it for cooking. Here's a link to an Extension article on them. Note that, while they need moist soil during their growing period, they should not be overwatered or be in standing water, and that they need high levels of phosphorus (the second number in the fertilizer XX-XX-XX equation.)
Elephant ears are very large, rather fast growing plants that need 3 to 5 FEET between them and are described by this Extension article as an "aggressive, spreading plant." These plants remain in the soil and are perennial (meant to live for many years.)
My concern about planting them together, whether in containers or the garden, is that you're going to be removing the ginger to use every 6 to 8 months, meaning you have to disrupt the soil the from 4 to 6 inches, and potentially 8 to 12 inches across. I think that would be disadvantageous to the Elephant ears, which have large root systems.
I would recommend planting Elephant ears in your garden, giving them plenty of room to expand, and planting the ginger in containers no smaller than 10 inches diameter. You won't disrupt the Elephant ears when you harvest the ginger, and won't have to worry about water drainage for the ginger if your pots have holes to drain well.
Hope this is helpful. Good luck!