How to Protect Ceramic Flower Pots From Cracking in Winter
As a gardener, I am always purchasing new ceramic pots for my garden. They are great for adding color to areas where you can’t put plants in the ground. But last winter I was reminded that ceramics can come out of a hard freeze with cracks and cracks. (As someone with a legitimate education in ceramics, I should have known better, but we all make mistakes.) If you live in an area that may experience freezing temperatures, you should also take steps to protect your outdoor ceramics during the colder months. .
Why does ceramics crack in the cold?
The clay from which pottery is made is composed primarily of silica, other minerals and water. If the clay is heated to the right temperature in a kiln, it is considered vitrified: the silica turns into glass, all the water disappears, and the product should be very durable. Most importantly, it will not be able to absorb water, which is important if you are making, say, a vase. However, most ceramic flower pots are made of terracotta clay and are deliberately under-fired so they leak water, which is why these cheap red flower pots tend to break and crack easily. And unfortunately, even many expensive large glazed ceramic pots are made in bulk and are not fired to the correct temperature. As a result, the clay can still absorb water. In cold enough weather, water expands and freezes, causing pots to break.
Remove pans from cold
Under the most ideal conditions, you bring your pots indoors for the winter. Store them in a garage or shed. These include ceramic pots, garden tags or sculptures, and even ollas, ceramic watering cans that have become popular. It is clear that this is not always possible. You may not have enough space, or you may have potted plants that won’t last all winter.
Raise and insulate your pots
Use bricks or wood to raise the pots off the ground so water can drain more efficiently, and perhaps protect against some freezing. You can also insulate the pots by wrapping them in burlap or even bubble wrap. Every little bit helps.
Water displacement plan
The problem isn’t just that the planters themselves retain water. If your pot is full of soil, and that soil is wet and then freezes… you see where I’m going with this. One way to solve the problem of soil expansion is to fill some of the negative space in the pot with an empty water jug. The plastic jug will shrink, making room for the frozen soil around it. This is a common method for filling space in pots anyway, as it means you need less volume of soil to work the plant and you save some weight.
Seal ceramics
If you’re determined to leave your pottery outside (hey, me too), you may want to consider sealing the pottery to prevent water from absorbing into the clay. There are all sorts of spray, dip and paint sealers available for this purpose, and as long as you make sure you get every nook and cranny really well coated, this should help prevent water from soaking into the pot and therefore cracking.