Much of the U.S. is entering freeze season—and I’m not talking a light morning frost, but a full-on freeze, which is a transformative event for your garden. While ideally we’d all be planting natives that are well-accustumed to our local climate, it’s not always realistic. We like what we like and are often willing to stress-test plants to achieve the landscaping we want (which is why we have orchids growing in our bathrooms). That means more work helping those plants through a heat dome or a freeze, so you’ll need to stay on top of weather alerts.
Through the extensive network of gardening groups I belong to, it’s rare I’m surprised by a frost or freeze. The message boards will light up with alerts and questions. But I am haunted by the surprise snow of May 2022, where I lovingly placed eight flats of tomatoes, peppers and eggplants that I’d been growing for months outside for their first overnight, and woke up to a blanket of snow. I stood at the door, rubbing my eyes like a cartoon, hoping I was seeing things. So now, I get notifications right to my phone. Information is powerful.
In addition, here are the three other things I do the night before a freeze.
Water before a freeze, even if it seems counterintuitive
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If the weather before a freeze is dry, and you’ve already bled your drip or sprinkler system, get out there with a hose and get your plant roots wet. I know, it seems strange. But the water will insulate the roots, and give the cell walls of the plant enough insulation to prevent cold damage. It also improves the plants ability to absorb any heat from the sun, however scant it may be. Even better, as that water evaporates, it creates humidity, and that retains heat better than dry air. The key here is how much you water, because too much can also cause damage. You want moist soil, not soaking wet soil.
Warm them up a bit—with old holiday lights
Before the great onset of LED holiday lights, there were incandescent bulbs, and those bulbs emitted heat. That’s not so great for lights attached to the house, but is great for giving plants a few degrees of extra heat. A longtime gardeners’ hack is to wrap plants that need a little extra care with these lights the night of a freeze. They also work spectacularly to keep hummingbird feeders from freezing. Best of all, they tend to be free, since most people have moved to much more efficient light strings—but if you had to, you could buy some.
Use the right kind of blanket to tuck your plants in
We’re humans, so when it’s cold, we wrap ourselves up. It makes sense to think about doing the same for your plants, but they have different concerns. Winter burn, for one, which is a result of dry soil and whipping wind. Watering helps, as I mentioned. But if you’re going to shroud your plants, it’s important to use the right kind of material. You want the plants to be able to breathe, so materials like burlap are best. You should never use plastic, which will keep moisture against the leaves, and trap heat. Yes, you want heat, but you want it to be able to escape, too.
You don’t need to be overprotective, either. Young trees and shrubs might need the help, but your established plants probably don’t. Notably, flowering trees like azaleas, camellias, and rhododendrons need protection only from the most extreme cold.