How to Overwinter Your Garden Plants

Winter comes every year; it’s crucial to letting plants and crops rest before the spring. However, winter also brings hurdles to overcome. Planning for these hurdles in advance means that you’re prepared, your plants are kept safe, and that spring will come without you having to do any damage control. By following certain strategies you can overwinter garden plants safely and prolong their life!

Don’t let the name fool you, though. Overwintering needs to happen much before the equinox. In fact, it needs to happen before the first frost of fall. Many plants need overwintering, such as:

• Herbs
• Geraniums
• Tropical bulbs
• Potted trees
• Vegetables

Let’s go into the details of overwintering in case you haven’t taken on this task before. If you have, we bet you’ll learn something new!

The Basics of Overwintering Garden Plants

Many plants thrive well into the fall, giving you the false impression that they’ll be okay during the cold months. Once the temperature drops, though, sadly, they won’t survive. Overwintering involves the simple task of bringing them indoors during the snowy, windy, freezing months.

Of course, there are many climates and sub-climates within our country and world. Plants thrive best in their native conditions, but those that aren’t suited to your particular winter weather will be fine with some help. Thus, check your area’s hardiness zone and cross-reference the plants you have in your garden.

Many plants that enjoy the outdoors during the other three seasons do quite well inside for the few (or more) winter months. Others instinctively go dormant and can even be stored away in a dark, dry room such as a basement or garage. Plants usually fall into either of the two categories, though.

Plants that Can Overwinter in the House

These plants can be brought inside and given some extra TLC when it’s cold outside.

• Begonias
• Caladiums
• Coleus
• Hibiscus

Find a spot for these flowers that give them light as well as humidity. However, you’ll want to keep them away from heat ducts. Although you want the heat blowing on your hands and feet so you can stay toasty, that direct hot air is too much for this sensitive flora.

Garden Plants That Can Overwinter in the Garage or Basement

If you don’t have enough space to have all your plants take up a shelf or floor space in your living room, bedroom, or bathroom, many will do just fine in the dark spaces of the garage or basement.

• Bulbs (e.g., tulips, crocuses, daffodils)
• Corms (e.g., cannas, dahlias, certain lilies)
• Tubers

When you prepare to bring these in for overwintering, cut away the foliage and gently dig them up from the soil. Then, settle the roots in a cool, dry area.

Specifics for Certain Plants

Of course, a general overview is great for understanding the theory behind something and why it works. It takes some practice and further knowledge, though, to get the gist of overwintering particular species of plants.

Geraniums

Geraniums are traditionally grown as annual plants. However, they are biologically perennials that can grow through the seasons—with a little encouragement.

Each year, check the almanac for the frost dates for the year. Just before, trim your precious geraniums back to about six or eight inches of foliage. Lift your plants out of the soil and cut back the excess roots.

Then, choose the smallest pot into which you can fit the newly trimmed plant. These pots should just fit the root balls. Fill the rest of the pot with fresh soil and keep them in the outside shade for a week or so. This way, they won’t be shocked by the transition. (Yes, plants feel shock, too!) After a week, choose a sunny indoor spot for your geraniums to overwinter.

These flowers will grow a bit during these cold months. When that happens, cut off the old leaves. Once spring arrives, you can transfer them back into the ground in your outdoor garden. Save the tiny pots for next winter!

Potted Trees

Perhaps you have some small trees growing in containers. Container trees don’t have the same insulation that in-ground trees do, which will cause the root balls to freeze in winter. Frozen water inside a plant cell means a tree that won’t come back to life.

If your trees are tropical, they must be brought inside into a warm, humid room. If they’re semi-hardy or hardy, they can also go into an insulated garage or basement, or you can insulate the container itself.

Cold Frames from Raised Beds

Many vegetable crops do well during the winter inside of a cold frame. You probably won’t need to start from scratch with this, though! Do you have raised beds for some of your produce? You can turn these into cold beds to protect your tender greens from the cold and frost.

Take a raised bed and repurpose some old windows. (Ask some local construction companies if they have old ones that they were planning to toss!) Create a frame out of scrap plywood. Leave some space for shrinking and expanding. Then, place the frame over the raised bed to create a greenhouse-like effect.

In this frame, you can grow many delicate plants during the winter, such as:

• Carrots
• Collard greens
• Lettuce
• Mustard greens
• Radishes
• Spinach
• Turnip greens

Once your plants are germinated, you don’t even have to water much! A cold frame like this serves a dual purpose as a terrarium, which fosters lush growth.

If temperatures fluctuate often or if your garden space gets a great deal of sun even though it’s cold, here’s a pro tip from Stoney Creek Farm. Place a small thermometer inside the cold frame. When the inside temperature gets above 80°F, crack open the window so that your plants don’t wilt.

Conclusion

Some plants, such as shrubs, perennial trees, vines, and certain flowers, overwinter themselves naturally. Others, though, need your special care and attention to survive the colder months. Get ready for overwintering now before it’s too late! After a few years, it will become second nature and a treasured part of your annual gardening routine.