The 14-inch pot came apart in my hands like a dropped dinner plate, in three clean pieces, with the frozen block of soil and the thyme still standing in the middle. That was Sunday. By the end of the afternoon I'd found two more cracked pots on the porch, and I'd learned something I probably should have learned years ago.
What happened
We had a rough stretch at the end of January: a thaw that got up to 48 degrees and soaked everything, followed a couple of days later by a night down to 9. Terra cotta is porous. It drinks water and holds it in the clay itself, not just in the soil. When that water freezes, it expands, and the pot splits along whatever weak spot it has. Meanwhile, the wet soil freezing inside pushes outward too. A pot full of damp soil sitting through freeze and thaw is basically doing that to itself over and over until it gives up.
The three that cracked had all been left on the porch with plants in them, on purpose. The thyme and sage are tough perennials, and I picked from both for Thanksgiving. I figured they'd sleep through the winter in their pots on the bench. The plants seem fine, actually. The pots are not: the 14-inch, a 12-inch, and the long rectangular one the sage lived in. Maybe $60 of terra cotta altogether.
Where they sat mattered too. Our porch is covered and 8 feet deep, but it faces southwest, and that's the direction our winter storms come from. The far end of the bench catches drifting snow and blowing rain. All three cracked pots were at that end. The ones closer to the house, where the floor stays dry, came through untouched.
The inside of a broken pot is a surprisingly bright salmon pink, much warmer than the weathered orange outside. I stood there admiring the color for a minute before I remembered to be annoyed.
Which pots survive a winter on our porch
I went around and checked everything. Here's where things stand.
Galvanized metal: fine. The galvanized pots on the bench don't care about freezing, even though the soil in them freezes solid. The only issue is a little rust around the drainage holes, and that's slow.
Plastic buckets: fine, because I empty them. The 5-gallon tomato buckets were dumped into the compost and stacked in October. Plastic that sits in the sun for years does get brittle, though, and one bucket handle snapped last summer.
Fabric pots and grow bags: so far, fine. The six strawberry grow bags are huddled together against the house wall with shredded leaves stuffed around them. This is their first winter, so I won't really know until April. The empty fabric pots are folded in a bin.
The rail boxes: fine. They're full of cut evergreen branches for the winter and have come through several winters already.
Terra cotta: only if it's empty, dry and indoors, or at least upside down under the roof. The ones I emptied and stacked in the basement in November are perfect. The ones I left full of plants are in pieces.
Glazed ceramic: I own one, and I'm not taking chances. It came inside two winters ago and it stays inside.
What I'll do differently
Next November, the hardy herbs come out of terra cotta. The thyme and sage will go into plastic pots or into the ground by the back steps, where the chives already live, and the clay pots will be emptied, dried and stacked in the basement with the others.
I'm also not replacing the three broken ones right now. The 2026 garden budget has no line for new pots beyond the self-watering test, and the September clearance aisle is a better place to buy clay than April.
The pieces aren't going to waste. The big shards are sitting by the back door, waiting to be painted into plant labels, which is my favorite kind of February evening project. The small bits will go in the bottom of the next pot I plant. I know crocks don't really help drainage the way people used to think, but it makes me feel better about losing them.
The thyme is now in a plastic nursery pot at the dry end of the porch, a little surprised but alive. Gus didn't come out for Groundhog Day yesterday, as far as I could tell. I'm reading that as six more weeks of winter.
