As the years go by you find yourself collecting more and more garden planters. Many of them are very expensive or just ones that you love very much. So of course you want to protect them from Winters cold and damage. Here are a few tips that may help ease your discomfort.
Before anything you need to clean them out and clean them up. Of course this is only for garden pottery that is empty and being stored. Start by dumping the soil into a compost pile or recycle can. You will not be using it again so it has to go. You do not want to pass on any bugs, mold or fungus that may be growing in the soil so get rid of it and start fresh next season.
Use a wire or stiff bristle brush to scrub off any chunks of soil that are sticking to the insideof the flowerpot. Then mix a bucket of 1 part bleach to 10 parts water. Now scrub the inside with the bleach mix to disinfect the pot and make sure any thing that may be still attached to the insides are killed or removed. Let the pots dry completely before storing them in the garage or shed.
Ideally all garden pottery and planters should be stored indoors over the winter months. May planters are frost resistant but not frost proof. This means they can handle light frost but not freezing weather. If there is standing water from rain or drip system in the soil and the soil freezes, the water will expand and crack the planter.
If you are leaving the empty planters outdoors, try flipping them over and use bricks, pot feet or wood to keep them off the ground. You can cover the empty containers with a large garbage bag to keep the water off or cover with burlap wrap. If you can't flip them then just fill them with hay or mulch to protect them from the water and cold.
If you can't move the garden planters and need to keep them planted then you need to top the pots with mulch to keep the water out and the roots from freezing. We like wrapping the planter with burlap and string to help. Plastic bubble wrap works etc. We know it's not the most beautiful look but if it saves your planters from cracking it's well worth it.
The only exception for all the above information is a terra cotta flower pot. Terra cotta is porous and absorbs water like a sponge. This is healthy for the plants but obviously bad for freezing water conditions. If you can't bring them in, get the pots off the ground, wrap in a waterproof bag or tarp and move them under a roof eave so water doesn't directly hit them. If you can't do any of that then at least lay down a thick layer of mulch or hay to protect the top soil.
Hope this helps and you find some of these tips for protecting your garden planters from freezing during Winter work.