I have a large home in the city, however the land in my house is a landfill and the soil is not good, I want to grow corns in pots, how big must the pots be? I can put in high quality soil there.

ok for one, corn doesnt grow on a tree. it grows on a husk type of thing, and no i do not believe they can be because they have to have direct heating from the sun, that is why they are so hard to grow.

Corn actually needs a spacious area in which to grow, a pot will not be advisable.

Corn is however not very fussy and will share space with other plants such as squash, beans, etc.

If you want to grow them between othr plants in your garden itself you can do so with ease. Corn prefers soil pH of between 5.5 and 6.5. Furthermore you shoudl also do all the other types of soil preparations such as composting, fertilizing, etc.