I have double begonias in pots outsidewhich are beginning to thin out & I believe these can be saved for next summer. How can I save these tubers until next spring/summer. Last year I just left them in their original pots in the shed but to no avail.
They are not hardy and are killed by frost, which is what happened last winter.
They can be lifted from the pots now and have the soil and compost washed off. Then place them in a tray of peat or compost to keep them from drying out too much but they should not be too damp either. Place a layer of compost, then the tubers and cover with a few centimetres of compost. Place the tray in a shed.
The cover of peat should keep them safe from frost but if the frost is as hard as last winter, you might have to bring them into the house where the temperature is not as low,
Pot up in March.