Question: The time is here when I need to lift and store Dahlia tubers. Where I am partially successful in keeping them the old-fashioned way in a clamp like they used to keep potatoes, I am not successful with this year's named varieties from cuttings. How they produce such a magnificent show of blooms from stems that don't form a tuber is incredible. Your advice please – I know some people have their own pet way to do it. (B Nucon, Thetford)

Answer:

Dahlias are easy to grow but do need winter protection in Norfolk. They are tolerant of a wide range of soil types and situations but best planted in fertile, well-drained soil in full sun when danger of frost is over, usually May to early June.

During late autumn cut plants to the ground after the first frosts have blackened the foliage.

In mild regions and on well-drained soils, leave the tubers in the ground and cover with a 7.5-15cm (3-6in) deep layer of bark chips or garden compost to protect them from frost.

I know some people can get away with just putting a layer of old carpet over the plants and leaving them in the ground, even in the weather we had in Norfolk last winter.

However, in colder areas or on heavy soils, it is best to lift and store the tubers and replant the following spring. Follow these steps and you should be able to get your dahlias through the winter:

•Cut down foliage and use a fork to carefully prise plants out of the soil.

•Dry off naturally and then clean away any soil clinging to the tubers. Trim stems to 15-20cm (6-8in). If the tubers have been washed, position them upside down in a cool place for a few weeks to dry off.

•Trim off any fine roots.

•Place tubers in shallow wooden boxes or open trays and pack with a peat-free compost or dry sand, just covering the tubers but leaving the crown exposed.

•Store in a dry, cool, frost-free place. If stored in a garden shed cover with newspaper if a hard frost is predicted.

•Inspect tubers regularly during winter for rotting and discard any that are unhealthy.

•This article was first published on December 24, 2011.