I planted five Begonia (Fimbriata) bulbs in a pot in early June this past summer on my patio in Toronto. They grew and bloomed beautifully. Can I save the bulbs and replant them next summer? If I can, how do I store them for the winter months. Thank you for your feedback!!
How wonderful that they performed so well for you and that you plan to over-winter them! The type of begonia you have are referred to as tuberous begonias and they require a winter dormancy.
If you have not already done so, dig up the begonia tubers when the foliage starts to yellow. Cut the stems to about five inches, and allow tubers to dry indoors at room temperature, out of direct sunlight, until the remaining stem pieces are dry and loose. You can then pull off the stems and any roots or soil, but there is no need to wash the tubers. Place them in a perforated plastic bag or in a cardboard box filled with peat moss or vermiculite and store in a cool, dark place at a temperature range of 40 to 50 F. A spare refrigerator can be an ideal place to store tender bulbs and tubers. Check the tubers occasionally for rot or softening and discard bad tubers immediately.
In early spring the tubers may be replanted in fresh soil and given a head start on the season in a bright windowsill where they do not become chilled. The tuber should be planted so that the upper surface is at the surface of the soil and no deeper. When planting the tubers, water them well with a light fertilizer and do not water again until either the soil dries or you begin to see new stems emerging from the soil.
If you are interested in learning more about begonias and other ways to propagate them, please see our Garden Guide on this topic here: https://www.torontomastergardeners.ca/gardeningguides/growing-begonias-indoors-a-toronto-master-gardeners-guide/
Good luck with your begonias and I hope they put on another beautiful display for you next summer.