On 23/09/2013 20:47, Bertie Doe wrote:


"David Hill" wrote in message ...

On 23/09/2013 14:24, Bertie Doe wrote:
On part of the Allotment (500' and exposed to easterlies) I have a patch
5 x 6 of 30 dahlias. In the past, every November, I have lifted and
dried and stored them in the loft.

2 probs with this method - some of the tubers cover a large area and I
don't like splitting them. Leaving the tubers uncovered for the Winter
is out of the question. I've lost established fruit trees and a 5 year
old Wisteria, in recent Winters.

Main prob, my back isn't so good these days. I'm aware that porous
membranes are good. However, I have some black heavy tarp which covers
the area perfectly. Question : Would the lack of water penetration for
say, 3 months, be detrimental to the tubers?


I get the impression that you replant the whole clump of tubers each year.
It is best to divide them as you will get much better quality.
Are your 30 dahlias all different varieties?

Just 2 duplicates (comet) the rest are different. Q. If you had a clump
with say, 6 tubers, would each tuber produce a new plant?


Not every tuber will produce a new plant, it depends on the eyes that
form at the top of the tuber where it joins the stem.
I was going to say if you had several of each variety lift some of each
and leave the others in the ground, covered as you described.
It's mostly the wet that kills off the tubers, though they wont take the
tubers getting frosted.
As for lofting and dividing, there are a lot of clips on google that
show you what to do, mostly with first year tubers, this American one
shows a clump that is a little larger, and despite her American
pronunciation of Dahlia it is quite good.
http://www.finegardening.com/how-to/...g-dahlias.aspx
The Americans split their dahlias down to "Chicken Legs" that is single
tubers with one or two eyes, in the UK we tend to grow from cuttings or
from clumps of a few tubers.
if you have more questions I will try to answer them.
David @ what today was a dull but dry side of Swansea Bay.