How to Winterize Your Begonias
Begonias need a little extra attention to carry them through the winter, depending on the area of the country. There are two basic methods: bring the begonias inside or protect them outside. The method to use depends on whether there are heavy frosts and/or lots of precipitation.
Winterizing Begonias In Colder Climates
There's no question that begonias need more protection in areas with heavy frost/snow, typically the northern climates. Here are the steps to winterize begonias in these areas.
Step 1 - Trim And Dig Up In-ground Begonias
For begonias that are grown outside, you can't just dig up the entire plant from ground and expect it to thrive indoors. Begonias planted in the ground grow faster than potted ones, so the rootball is likely fairly large. Trim back the plant so the tops match the size of the rootball. Then, dig it up.
Step 2 - Place Begonias In Pots
Next, place the trimmed and dug-up begonias in pots sufficient to contain the rootball. Add potting soil as needed.
Step 3 - Bring Inside To Well-lit Area
Begonias need an indoors location that's well-lit and has adequate humidity. Placing in a single layer dry location is best, perhaps on a bench or table. Fluorescent lights are best.
Step 4 - Watch Humidity Level
A tented light stand can help keep humidity at the appropriate level. This cuts down on watering and promotes healthier plants. Use a clear, nonflammable plastic and make sure it doesn't directly touch the light fixture. Some gardeners place the pots on trays filled with gravel or coarse perlite. This allows the water a place to go and keeps the humidity at the right levels. Other gardeners with only a few plants like to use an aquarium, or mist the potted begonias frequently.
For Potted Begonias
Winterizing potted begonias in colder climates simply requires bringing them inside. Follow steps 3 and 4 as above. Application of a fungicide or neem oil can protect plants from insects and mildew in all cases.
Winterizing Begonias In Warmer Climates
It's a lot easier to protect begonias in areas where there's no frost. In some warmer Western climates, they can remain in the ground year-round.
Step 1 - Move Potted Begonias To Protected Area
Begonia aficionados know that the plants will tolerate cold better than they can wet conditions. It's been said that begonias don't like wet feet. So, protection for the winter in warmer climates means moving the plants to an area out of the wind and rain, such as a porch or under an awning.
Some gardeners construct a shade house with plastic sheeting open to one side to allow for any necessary watering.
Step 2 - Occasional Frost
In areas with occasional frost, in-ground and/or potted begonias left outside can be covered with an old bed sheet. Or, use a large cardboard box. Another suggestion is to use one of the newer plastics that have microscopic holes in it to allow air and water to pass through.
Step 3 - Mulch
Some areas only have infrequent frost. To best protect begonias from frost damage, watch the weather forecast. Trim back the plants and mulch heavily.