Posted: 17/10/2012 at 13:46
Dahlias are lovely and so worth the effort, but up here in the north east of Scotland they can be really tricky to lift ( once frosted ) and dry out and store. More often than not even storing them upside down in a greenhouse will result in rot. Here's what I do:
1. Once frost turns foliage black, cut back, lift tubers, shake off as much soil as possible
2. Get them indoors, in a garden sieve and put them on top of the boiler or somewhere with an even gentle heat to dry out ( airing cupboard for instance )
3. Once COMPLETELY dry and looking wizened, I wrap them in newspaper and store them in cat litter! This is, of course, highly absorbent and your tubers should come through the winter and be ready to plant out into pots the following spring. The slightest trace of moisture and they will rot.
We used to have cats and when they'd 'gone' to the Great Litter Tray In The Sky we had a big brewing-bin in the boiler room full of unused kitty litter - and the dahlias have never looked back! I do have to leave myself notes hither and yon, to remind me of their existence, but good old fuller's earth does seem to do the trick.