Are you talking about Dwarf Bonanza peach? How big is the pot?

Milehighgirl is the expert on trees in pots, but I will attempt to sort out your climate...

I guess you've recently moved from zone 9 Las Vegas to zone 6/7 Reno.

You are in for a surprise if you think that freezing weather will only occur during a record cold spell (that sounds more like the Las Vegas climate)... In fact, your average nighttime temp will be below freezing for the months of November, December, January, February, March, and April. December and January average lows are around 20 degrees, and in a typical winter you will get down to around zero once or twice.

This means a peach that is rated to zone 6 might struggle in a pot, since potted plants are typically a zone or so less hardy than in the ground plants. You could always bury the pot in the ground for the winter, which would also reduce your already limited watering need over the winter. I'm sure Milehighgirl will have some more specific advice on this...

You can peruse the climate data at the link below, which is the climate summary for the Reno airport.

http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?nvreno

you are right, I moved to Reno and brought my potted trees with me haha...We are USDA Hardiness 7a. It is a Dwarf Bonanza, hardiness Zone 6-9. It's pot is prettylarge, around a 19 gallon. The way I understand it, bringing it inside will be bad because it needs to have enough cold weather...but too cold of course is bad...I cannot bury it for now unfortunately. Would wrapping the pot in the hot type christmas lights help? I know people use the hot christmas lights to keep citrus warm in vegas for the very cold nights. not sure how much that would help my potted peach though. it looks like I am on the borderline for the bad days out here. any other ideas to keep the root ball warm would be great! I can try and wheel it into the home closet on my porch when I see a forecast of below freezing.

fabaceae_native gave a good description on what you are up against. You cannot bring your peach inside because it does need the chill hours and it does need to rest.

The roots are the most sensitive part of the tree. When I was planting my potted trees in October or November I was not able to get them all in the ground before the ground froze. We had a little warming spell and so I thought I could plant the rest that I had holes dug for but it was already too late. The roots had frozen and the next spring none of them showed any signs of life. Personally I would not suggest the lights either since it would produce too much heat and tell your tree to break dormancy.

I don't thoroughly understand your situation as you say you cannot bury the pot in the ground. The only other alternative I can see would be to mound up a significant amount of dirt around the pot. I'm talking several feet wide. Then you would have to put something around the dirt to keep it from eroding during the snows. I think if I were in your shoes I would build a temporary structure out of cinder blocks then put the pot inside and then fill it with dirt. You will have to be aware that this situation would make a nice habitat for mice and voles so you may wish to wrap the trunk in hardware cloth. If you did this then you could also mound up leaves on top to add an extra layer of protection.

Maybe someone else has some more insight that can chime in.

Vegas:

You are right that taking the tree indoors is a bad idea. Too long and it will lacking chilling or bloom too early. Better to keep it outside and try to keep it from getting too cold.

You could try the lights and put insulation over that. Anything to keep the rootball from getting too cold. I'm not sure how cold is too cold for the roots. I'd be concerned below 20F but they might take much colder. You only really need to be concerned when air temperatures are below 10F for several days.

milehighgirl I cannot bury it because I now live in a condo with a small porch. this porch however does have a closet. With leaves dropped, do these trees even need sunlight? Because the porch has a closet that is attached to the house, and I can stick it in there. Should be similar to a garage then in temperature I think.

actually I guess it depends on how well this closet is insulated. I can just see as it starts to get colder, what the temperature differential is between the closet and the outside. If this closet works out well, how cold do I let it get outside before sticking it in the closet(if the lack of light is indeed ok for the dormant tree).

Without leaves it needs no light and water maybe once a month. The ideal storage temperature is 20s and 30sF. Above 40F will force early growth. So something that would take the edge off the coldest without begin too warm is best.

I think on the colder days, the closet should be able to keep tha temp. I think it's insulated...I'll play it by ear this winter and see if I can keep it healthy. Should be able to plant it in the ground next year, so see what I can do :)

Probably OK in the porch, surely OK in the closet. Almost certainly OK outside, if you could protect the pot (say, cover it under a mound of leaves).

When I read my previous post again I realized that I must have PTTLS (Post Traumatic Tree Loss Syndrome).

lol, well hopefully I can make it through the winter with it. Lemon tree is lucky that it stays green year round and will be cozy in the house. probably will flower and give lemons too. but not as useful as my peaches lol