During this season I will be planting a bunch of window boxes and whiskey barrel planters. It is up to me what goes in them. Can anyone suggest any perrennials that will survive a Wisconsin winter in there? Also I was thinking I would make my own potting mix, recipes anyone? Our county recycles yard waste into compost. The end product is available for free. It is a fine dark crumbly finished compost. If I incorporate this in my planters do I need to sterilize it first? I don't want weeds or fungus to become a problem. How can I sterilize like a yard of this stuff. I did some plantings last year with mums, gonna go see if any survived next week.