It doesnt hurt to try and imagine growing a coconut palm in a zone 4! Its important to keep it moist but in good draining soil so its not in standing water. Also keep it warm and in sun. Your nights are probably pretty cool even in the summer so that will slow the growth down but as long as the days are mild it should be okay. Once night temps are in the low to mid 40s its time to bring it in (especially once you get close to the 30s) and if it warms up again you can bring it out. When indoors keep it away from a heater but in a warm area by a bright window if possible. Dont keep it too moist indoors to keep it from roting. When they go outside again for the year slowly introduce it to the sun so it doesnt burn.

I hope you have lots of success. Keep us updated on its progress!
Good luck!
-Alex

I agree with alex,,except I would never let it see low 40's,,,why chance it,,,low 50's yes,,,

I say go for it. Its always worth a try or two:) I would love to see a pic of it now, and at years end:) Good luck!