When we think of cacti, we usually picture scorching deserts, but these prickly survivors are actually tougher than they look. In fact, some varieties are so hardy they can handle bone-chilling temperatures down to -13°F (-25°C) right in your backyard! However, if you want your exotic green friends to make it through to spring, you can’t just leave them to fend for themselves.
Here’s the lowdown on how to help your outdoor cacti survive the winter:
Keeping Outdoor Cacti Dry: The Golden Rule
To survive a freeze, cacti have a pretty cool built-in trick: they reduce the amount of water inside their tissues. This increases the salt concentration in their cells, which basically acts like natural antifreeze to lower their freezing point. You can give them a helping hand by making sure they stay as dry as possible during the wet winter months.
Outdoor Cacti: Protection from Top to Bottom
First things first, your cacti need to be living in loose, well-draining soil. If you’re just getting started with planting cacti, always remember to add a solid drainage layer (think gravel, clay pebbles, or broken terracotta shards) at the bottom of the hole. Once winter hits, you’ll also need to keep the rain and snow off their heads:
- If your cacti are in pots, move them to a spot sheltered from the rain—like under a porch or an eave—before the first frost hits.
- For cacti planted directly in garden beds, you can build a simple “rain hat.” Just use four stakes and some clear greenhouse film to create a transparent roof that lets light in but keeps moisture out.
Pro Tip: To help your plants naturally “dry out” and prep for the cold, stop watering and fertilizing them entirely by late August.
Winterizing Potted Cacti
If you’re planning on overwintering a potted cactus outside, you absolutely have to insulate the container. Without a little extra padding, the soil inside the pot can freeze solid in no time, which is bad news for those sensitive cactus roots.
To protect them from the rising cold of the ground, set your pots on a thick piece of Styrofoam or a wooden block. For the sides of the pot, wrap them in several layers of burlap or a specialized garden fleece (you can find this easily online or at your local garden center). This keeps the root ball cozy even when the wind is howling!
