Hi Donna,
er
You could do either however unless you plant them all together a 30" pot would be kind of large for a few. Whether you plant in the ground or in pots make sure you use a quality organic based soil-that is one that has good natural ingredients. I really like Miracle-Gro potting soil and my callas do to. They should receive full sun and keep the soil moist. Be careful not to overwater until you see the stems growing up through the soil as they could rot but once they start growing keep it moist but not wet. Come fall you will need to withhold water starting in late September or so as that will trigger dormancy. Once the foliage turns yellow and collapses they will have gone dormant and should be kept in a cool dark place for the winter. I take mine out of the pots once dormant and replace with fresh soil then store for the winter.

Scott

I have had beautiful callas in pots for several years- in northeast--did not realize i could save them--now i know--but THIS year i have 5 plants that came up in the garden--not the pots--1 has bloomed--a big yellow flower--much bigger than what was ever in the pots--a standard size--I am wondering if they survived begin tossed in the garden as old pot dirt. Did not think Callas could survive the NE winters--though I just saw a garden mag that says they have that now. Any opinions on how these callas made it through our horrible cold winter this year?