There is so much to love about a good container garden. Pots let you experiment with color, move plants around when a border needs a little extra something, and squeeze more greenery into even the smallest outdoor space.
The trouble is, when fall arrives and the first frost is on its way, all of those lovely pots? Well, they need a little extra attention if you want them to make it through the winter unscathed. (Something I learned the hard way during my early attempts at gardening; it was devastating).
Thankfully, my husband is a professional gardener, so I’ve learned to listen when he starts talking about protecting plants for winter. Because, while I’m tempted to leave everything where it is and hope for the best, he has put a lot of effort into teaching me that a little preparation now can make all the difference to how well plants survive the colder months.
What Your Container Garden Needs Before The First Frost
Temperatures are a little erratic this year, thanks to the ongoing El Niño, and things are set to be just as wildly unpredictable this winter. Planning ahead, then, is more important than ever.
So, if you’ve been wondering what to do with your container garden before temperatures drop, these are the three jobs that my husband recommends prioritizing.
1. Move Tender Plants
When it comes to overwintering your container garden, my husband’s first piece of advice is simple enough: figure out which of your plants can handle the cold and which can’t.
“If you’ve got tender plants in containers, don’t wait until the first frost is forecast to start thinking about where they’re going to spend winter,” he says. “Move them somewhere protected while the weather is still mild enough for them to adjust.”
Plants in pots are more exposed to cold than plants growing in the ground, because their roots aren’t insulated by the surrounding soil. Tropical plants, tender perennials, and many plants that have spent summer outside may need to be moved indoors or into a frost-free greenhouse, conservatory, or garage, depending on their light requirements.
Top tip: Before bringing plants inside, check their leaves, stems, and potting mix for pests. It’s also worth moving them gradually into their new environment where possible, rather than taking them straight from a sunny patio into a dark corner indoors.
Shop Container Plant Winterizing Essentials:
2. Group Your Outdoor Pots
If you’ve got containers that need to stay outside, my husband advises you group them together in a sheltered spot. (Well, what he actually said was to treat them like penguins and get them in a huddle, but close enough).
Why? “It means they’re less exposed to cold winds, and you can give the pots a little extra protection,” he says. “Just make sure you’re grouping plants with similar needs, and don’t block drainage holes or leave containers sitting in water.”
Grouping pots against a sheltered wall can help reduce their exposure to wind and make them easier to protect. It won’t make tender plants frost-proof, but it can be a useful measure for hardy plants that are staying outdoors.
Top tip: Try to choose a spot that offers protection without becoming waterlogged, and raise pots slightly on pot feet or bricks if necessary to help excess water drain away. Good drainage is particularly important during winter, when cold and wet compost can put roots under additional stress.
3. Get Insulating
One thing people often forget is that it’s not just the foliage you need to think about. “The roots are sitting in a container that’s exposed to cold air on all sides, so I always recommend giving them a little extra protection before the first frost arrives,” says my husband. “You can wrap the outside of the pot with bubble wrap or hessian, and add a layer of mulch over the surface of the compost to help insulate the roots from temperature fluctuations.”
Terracotta pots can be particularly vulnerable to cracking when moisture freezes and expands, so insulating the container can be helpful in exposed conditions. Bubble wrap provides an extra layer of insulation around the pot, while hessian is another option for wrapping containers.
Mulching the surface of the compost adds another layer of protection, helping to reduce temperature fluctuations around the roots. Well-rotted garden compost, manure, bark chips, straw, or shredded leaves can all work well, depending on the plant. “Just be sure to keep the mulch away from stems and crowns, and make sure excess water can drain freely,” my husband adds.
Top tip: the important thing to remember is that insulation can help protect roots, but it won’t turn a tender plant into a frost-hardy one. If you’re growing plants that can’t tolerate freezing temperatures, you’ll still need to move them somewhere sheltered or frost-free.
It’s important to remember that insulation is not a substitute for moving a frost-sensitive plant somewhere safe; the right approach depends on the plant, the container, and how cold your local winters become.
So, before the first frost arrives, check which plants need to move indoors, group the hardier containers in a sheltered spot, and protect exposed pots from the worst of the cold. It doesn’t need to be an enormous job, either; honestly, just little time spent preparing now could help protect your plants through winter and leave you with a healthier collection to enjoy when spring comes around.
You can’t ask for more than that, right?
