How much precipitation do you get, Bathgate, do you have reasonably dry winters? And forgive my ignorance, but I have some vague idea there's a difference between New York city and New York, or is that not the case?

For the past 3 years, we have a good amount of precipitation. We were under a foot of snow cover for the whole season with a blizzard every week or so. Average temperature was about 28°F. I'm in grow zone 7. New York City is lower New York State.

I only asked because I was surprised that you say the temperature doesn't often go below zero, but I didn't notice you meant zero F, not C! That's cold, cold.. and way too much snow, they'll have to come up. Instructions for overwintering in the link below, you'll have to scroll down

http://www.gardeners.com/how-to/how-to-grow-dahlias/7125.html

thanks

Well I'm a little over an hour and one half from New York (I'm south ). Just planted mine this past spring. Bathgate, we have the same weather, I'll leave mine in as an experiment (I would faithfully follow Bamboo's advice but I will do this out of curiosity). If curiosity doesn't kill this old cat, as the saying goes, by next season, I will post the results.

The last time I tried to store lily bulbs in my basement. They all became like dried up little prunes or lumps of dried clay.

Lily bulbs have little resistance to dehydration, so they are best stored in moist soil, in the ground, if they are hardy in your zone.