The material that our window boxes are molded from is designed to be able to be left out in all seasons, in all weather conditions, including the coldest of Winters.
There are just a couple of recommendations we do make when leaving your window boxes up throughout the winter:
1) Make that your window boxes are draining properly by ensuring that there is nothing blocking the overflow drain hole(s) at the bottom of your window boxes.
2) It is usually a good idea to slow the amount of water you are putting in your planter once temperatures begin to reach freezing to limit the amount of excess water that is in the reservoir. There will always be water left in the reservoir and that is fine, our double-walled design will allow room for the water to expand during freezing so there is no risk of cracking.
3) Should you receive an exceptionally large snowfall, we recommend you brush snow build-up, off of the top of the window boxes to avoid excess weight from snow/ice weakening the wall mount brackets.
4) The wall-mount brackets are painted with a rust-resistant coating however it is a good idea to inspect them every year or two for any signs of rusting and sand and re-paint as necessary.
If you would like to bring your window boxes indoors to store for the winter and want to remove all of the water from the reservoir, you will need to have drilled the optional fill port/drainage hole as shown in the planter's instructions. Your window box should have come with a 3/4" plug for this option. if you are missing or miss-placed this plug just reply with your address information and we will be happy to mail these to you at no charge.