Plants in pots do not have the same amount of soil protection as a plant in the ground. The roots of a potted plant are often very close to the pot if not right on it. The penetration of the cold causes die back of the roots. I don't keep much in pots because of the extreme temperatures we have, and generally what I have are plants that I didn't have time to get into the ground. I have learned the hard way that the best policy is to sink the pot into the garden for the added root protection. If you are talking about a pot that you cannot do this with, then I would wrap, wrap, wrap it so it is very well insulated. Colleen - 4100 feet, high desert, zone numbers seem to be just for discussion. -----Original Message----- From: pbs-bounces@lists.ibiblio.org [mailto:pbs-bounces@lists.ibiblio.org] On Behalf Of Jim McKenney Sent: Friday, October 05, 2012 4:56 PM To: Pacific Bulb Society Subject: Re: [pbs] Cold hardiness of potted plants left outdoors in winter J. Denys Bourque wrote: "I suspect that dessication due to wind effect may be the cause that plants in pots left to overwinter outside die, particularly if snow cover is lost." You might be right - we rarely have snow cover here, and desiccation is a likely cause with potted conifers in pots in the wind swept canyons of the inner city. But I've had this happen with plants in my own garden which were in relatively protected sites where wind and desiccation are not likely causes. Jim McKenney