How To Overwinter Coleus And Other Plants Indoors
Keep your favorite annuals thriving all winter with these money-saving tips.
There’s good news for cold-climate gardeners: you don’t have to let the frigid temperatures and snow destroy your annual plants like your favorite coleus. You can prolong their beauty by bringing them indoors for the winter. In addition to adding a burst of color to your living space during the dreary, cold months, the practice of “overwintering” can be good for your wallet as well. You’ll have fewer plants to purchase in the spring! Here’s how to get started.
What’s in store for winter in your neck of the woods? Get our extended forecast!
What Are Annual Plants, and Which Ones Can I Bring Inside?
Annual plants are those that are not hardy enough to survive year-round in certain climates; they will die with the onset of cold weather. (In warm climates, however, they may act as perennials). These plants are excellent candidates for overwintering indoors:
- Flowering kale
Before frost threatens your annual plants, get them ready for their vacation indoors. Here’s how to do it.
- Dig up the plants you wish to save or remove them from their pots. Be careful not to damage the root systems. You can cut large plants to a more manageable size but never remove more than 2/3 of the plant’s crown and roots.
- Rinse the roots. Use a garden hose and a gentle spray setting on the nozzle to rinse the roots. This will help get rid of insects or eggs residing there.
- Repot the plants into a clean container with good drainage. Use dampened, new potting soil – either a commercial mix or a recipe of two parts loam, one part compost, one part perlite, and one part coir (coconut fiber).
It is best if you can bring the plants into a cooler room, preferably with north-facing windows, for a week or two. It will help acclimatize them to your home, as well as keep them quarantined from other plants so you can monitor for evidence of insects on the foliage.
Typical pests include fungus gnats and aphids. Use yellow sticky tape traps to effectively capture them. As well, do not overwater—fungus gnats, in particular, love wet soil.
Location, Location, Location
After the quarantine period is over, you can move your plants into a sunny room for the winter. Keep them out of direct sunlight, which can scorch them, and avoid extreme heat or cold. Water consistently but remember that too much water will encourage rot and mold. There is no need to fertilize annual plants kept indoors over the winter.
In the spring, harden off your saved plants by leaving them outside in a sheltered location for brief periods during the day, returning them indoors at night. After a couple of weeks, they should be ready to plant out again.
An alternative to saving whole plants at the end of the next growing season is to take cuttings of your favorite annuals. To do this, next summer, cut healthy non-flowering shoots from the plants mid-season, and place them in moist growing media, such as perlite or coarse sand, to root.
Cover them with a clear plastic bag and locate them in a warm spot away from direct sunlight. Check on them frequently to ensure they do not burn or wilt. When they have rooted, they can be planted into pots to keep indoors. This is also a good way to propagate more of the annuals you love.
In addition to enjoying the color of blooms throughout the winter months, overwintering annuals can be good for the wallet as well. You’ll have fewer plants to purchase in the spring!
Be sure to check out our Gardening by the Moon calendar to pick the right days to do your planting.
Sheryl Normandeau, BA, is a Master Gardener and writer from Calgary, Alberta, Canada. Her articles and short stories have appeared in several international publications. She is the co-author (with Janet Melrose) of the Guides for the Prairie Gardener series.
i have indoors plants that need repotting Where is the “barren days” in the calendar???
i garden by the moon phase but also know there are barren days to follow i would love to see those in your gardening calendar