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The dried tubers can then be prepared for storing - in dormant state - for the winter months. This is done by simply placing the dried tubers in a cardboard box or a wooden seed tray, and placing in a dark place - frost free and not heated.
They should not be covered with compost - though a sheet of old newspaper will do no harm.
Inspects the dried tubers weekly, to ensure no signs of rotting or pests that may be over-wintering. If any rotting is found, then cut away the affected parts, allow the cuts to dry and dust with Yellow Sulphur powder.
For Tuberous Begonias which have been pot grown, then simply lay the pot on its side to allow compost and tuber to dry out. It can then either be removed, or left in the pot, and re-started again in the spring - in the same pot, but with a little fresh compost added. Be on the lookout for Vine Weevil Beetle Larvae if storing in this manner, and in any event, if said p[ests are a particular problem in your garden area, then remove the tubers from the soils and treat as above.
Restart you begonias into growth the following spring - ready to take cuttings if required - or for planting back out into the garden when the time is right.
Begonias General Information | Propagation of Tuberous Begonias |