What’s the best way to store tubers?
QThis year I grew begonia tubers in hanging baskets and containers for the first time in a very long while. Could you please tell me how to overwinter these as I have never been very successful in the past? Do I let them dry out in the container and leave them in the soil or do I have to remove them?
Linda Griffin, via email
AThe best way to overwinter tuberous begonias is to wait for the first light frost to discolour and kill the blooms. Then remove plants from hanging baskets, patio pots and other containers, and from borders, and tease soil or potting compost from the roots.
Consign plants to seed trays or other containers and move them into the greenhouse, which must be kept frostfree. When the stems desiccate and dry, and the leaves shrivel, very carefully snap the shoots from the tubers. Finally, place tubers in seed trays and just cover them with spent potting compost.
In March, reawaken tubers by placing them singly and crater-side uppermost into 4in (10cm) pots of loam-based John Innes No1 potting compost. Water them in and speed them into growth in a gently heated propagator or in plastic bags on a warm windowsill.