I use large clay pots with cow manure and potting soil. Add some limestone gravel and put a two inch layer of gravel in the bottom of the ‘large’ pot before adding soil mix and celery sprout. You will be amazed at how much root structure a healthy celery stalk generates. These roots once the stalk is cut off make excellent mulch for the potting soil.
I was wondering how much root space they needed. So I better wait until it warms up enough here to put them in the ground, since I don’t have large pots or a way to water them when gone.
My gardening problems - or learning how to garden - are because I’m gone to the mountains off and on during the summer. My gardens in the valley haven’t done well without attention. Although the weeds thrive! And what I’ve planted in the mountains, like raspberries and potatoes, haven’t done well when I’m gone because of a lack of consistent water.