I grew it this year and it is one of the crops I plan to grow again next year.
What I did was to start it indoors in late winter/early spring. Then when it was time to bring it outdoors, I planted it in a window box size pot -- 4 to the pot, spaced about 6" apart, more or less. Keeping them in a pot allowed me to move them around. But I mostly kept them on my deck, which is mostly shady. Celery needs to have moist, rich soil. My entire property bakes in the summer, because we have very little shade, so keeping the celery on the deck kept it cool and moist. Also, our soil dries out very quickly, so keeping the celery in pots allowed me to give them the richest soil I could get my hands on. They like plenty of compost.
I am still harvesting stalks of celery. We got hit with some really cold nights -- down to 11 degrees F. Since my celery is in pots, it was easy enough to move them to shelter during the cold snap.