Overwintering Dahlias

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I bought some reduced price Dahlias from the seed merchant I use and planted them in pots. This was for a supply of cut flowers. They have done very well and I wondered if I could just cut them back and leave them in the pots ( in a shed) rather than lifting them and drying them off to store them. The compost they are in is pretty dry. Things are getting colder here ( North of Scotland) and I feel I need to do something with them soon.

KajiKita

Yes, you can leave them in the pots. The foliage will die back naturally - as the leaves start to fade cut the stems back to a couple of inches. They need to be frost free so the shed might be a bit cold, but if they are dry that will help. I typically store them in my cellar but other people keep them under the stairs, porch etc.

KK 

twopenny

That sounds reasonable.
You'll need to check on them from time to time. As the foliage dries out it may rot down to the tubers.

If possible keep them healthy until they show signs of real cold so the tubers get fully fed then look online for how to dry store them. 

If you leave tin the dry compost that would be fine but you will need to give them new compost in the spring. They will have exhausted the food in the current lot.

Try and find one specific to Scotland. There's a tv program callled Beachgrove, might be something on their website.

comeandgo

They won’t survive the frost unless you have them well wrapped in fleece or have the shed heated.  

Woolsery

comeandgo said:

They won’t survive the frost unless you have them well wrapped in fleece or have the shed heated.  

Not many Scots I know would heat their sheds!  East or West of Scotland may be relevant, as is altitude. Is there a cool back bedroom perhaps? Down here in the tropical south, we used to put their dried out pots into our stone shed inside a well insulated box, even back in the days when climate change wasn't invented. Now, if we just did that, the vine weevils would get them, so it's remove compost first, then into a box of fresh, dry compost in the barn. No mousie problems here, but I don't know if that's a thing with them?  I suspect not.

elle_may

I'v left mine in the ground 5 of them and they have come up in summer for the last 5 yrs.  

Woolsery

elle_may said:

I'v left mine in the ground 5 of them and they have come up in summer for the last 5 yrs.  

 

I could too, with about 50% survival, but success or otherwise depends on location, soil type and maybe the number of slugs, so people need to bear those things in mind.

Fosterdog

elle_may said:

I'v left mine in the ground 5 of them and they have come up in summer for the last 5 yrs.  

I've left some in the ground with success too, as has my MIL who's never taken them out to overwinter them and has been growing them for 50ish years. However OP is in Scotland and growing in pots not the ground so there is less chance of them surviving. I get some of my pot grown ones survive and some die when I leave them in pots overwinter (without moving them to a shed or greenhouse).

Eldi_Dos

In North of Scotland you will need to be quick.

Take tubers out and cut and trim neck and roots then leave upside down on newspaper in dry and warmish location, no danger of overnight temperatures dropping to much. Once you feel tubers have dried out I used to put them  in terracotta pots with dry compost and then in cardboard box, maybe with some newspaper stuffed around pots. Keep box somewhere frost free and dry. Cupboard under stairs or somewhere like that. Think of a environment that a tortoise hibernating would be put. Then hopefully next April see how they did.

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Thanks to everyone for their help. I have lifted them and will leave them to dry out before giving them Eldi_Dos Tortoise treatment and a holiday under the stairs! Woolsery we are on the east coast and about 450ft above sea level and can get some pretty severe frosts as we are quite exposed. Hopefully they will survive and I can get another season out of them for cut flowers. Twopenny, I thought these were specific to Scotland as they were reduced in price! I will have a look at the Beechgrove website (didn't know they had one as I am not a fan of the programme) I recycle my compost most years by removing all the roots ( ditch any that has had a diseased plant) and mix it in a tub, I can seal, with well rotted farmyard manure and coffee grains. I haven't had a problem with recycled compost so far. Thanks again for everyones help.