Sandy soil freezes deeply because it doesn't hold much water. If weather is very cold without snow cover the roots can freeze. If you have reliable and deep snow the trees would be better protected.

Any kind of mulch around the tree will be inviting for the varmints. I've never had to deal with that but others poison with good results. The mulch would keep soil warmer.

Being your in zone 3, the sand will most definitely freeze. Rabbits can also be an issue. You might need to fence them all with poultry netting. If snow builds up around the trunks they can be girdled below the snow surface as well by mice and voles.

TurCre,

I've been growing fruits in pots since 2010. For winter, I drag them all together and pile leaves around the pots. I pile the leaves a few inches above the pots because the leaves settle to a lower level over the winter.

I live in zone 5, much warmer than you. However, last winter was brutal for us with stretches of -20. Even last winter, all my potted plants survived. (I lost of my fruit crop for 2014, but so did every commercial operation in my region.)

I haven't had a problem yet, however another forum member lost all her plants to rodents one year when she buried hers in leaves.

I used to live in Minnesota where we had snow on the ground all winter. Under those conditions, I'm guessing snow would work just as well. But make sure your pots are insulated at least up to the soil line. Early in the season, you might need to shovel a little to get the snow deep enough.

they will be fenced for sure. deer/bear/rabbits seem to love them. I was hoping a half acre of disc'd soil would be mouse/vole/shrew free. I like the poison idea, but I wonder what the options are? I hear mothballs might work? we do get plenty of snow ...100-150" annually.

Sorry. I should have addressed my post above to benfisher, not TurCre. Again, sorry about any confusion.

The best method I have found is to dig a trench, put the pots in, then back fill with the dirt you dug out. Don't fill with leaves or anything that vermin could nest in. I lost nearly $1000.00 worth of trees one year because the ground froze before I could plant them all. I put them in a trench and filled it with leaves (the trench was dug before the freeze), The next spring I found that mice had chewed all the trunks to a sharp point.

I like milehigh's approach. For over wintering you could bury the pot and tree much deeper than you'd plant. It won't hurt to have soil well above graft union over the winter especially in sandy soil. That will protect the scion from voles and freezing.

thanks guys. I dug them in tonight, and as I tried to fill the voids between pots I got an extra inch or two of sand in the pots, but I figured that should not hurt anything, right? burying them to the graft union should be fine the way people propagate rootstock- I might just get more roots if I leave the extra sand in ? I left my rootstock longer than most due to poor scion sizing. Is there a reason nursurys graft tight to the root?

I'd pile an extra 6-8 inches around the trees. Nothings going to happen to the buried part over winter. Your soil will be near freezing in the next month in zone 3a. The buried part won't rot or root especially in sandy soil. I might be more concerned with sticky clay but not sand.

you are correct. unless we get some snow our dirt is very hard by mid November. as I dug them in I found a nice vain of large grain sand that digs easily..... I think I'll give them a good cover next trip out to the farm. thanks again