I don't know your zone
so unsure of your temps.
Do you know what kind you have?
Are they pups or plants?
I'm TX zone
8b & coastal. I have hardy basjoo I leave in ground,but dug my largest one with a 1 yr plant and 5 pups for relocateing. (I'm working the bed durring winter so don't sweat 5 gallons a minute) I dig my dwarf cavendish& lil prince. they are zone
9ers.I just dig& set in pot.I don't have to water cause they store enough water. My basjoo was a WORKOUT. Its sitting in trashbag.
Here's where I hang for naner info. i've not found a better place & even have a few new ones.http://bananas.org/index.php
I recieved my dwarf cavendish last year. I potted it kept in kitchen,barely watered. I'd wait till ground warms up to place in ground.When spring
comes start setting the pot outside then in May put in ground. They grow better when are warmer. I tried setting out in 2nd week of April. My prince turned pale& cavendish slowed growth.