what to do with dahlias overwintered in shed?

[useruserna]

Hi, my dad, who liked his dahlias, died early this year. He had dug them up some time last year and they are in boxes in the shed. Apart from one that looked like it was going a bit mouldy (which I chucked) they look Ok I think - kind of shivelled up bulby things. As you can probably guess I know nothing about them except they look lovely when flowering :) I think he used to plant them up first in pots before eventually planting them out - but I'm not sure, so could anyone tell me what I should be doing with them to get flowers this year as I'd really like to keep them going. I'm in the S.E. Thanks

That's a lovely thing to do. I overwintered mine in the shed for the first time this year so I'm no expert but I'm planning on starting the in pots in the next month or so indoors and then planting them in the ground when the risk of frost is over and they are big enough to stand up to the slugs. Good luck with them.

Thank you.

I just want to say, I have never dug up my dahlias and they have survived the harshest of winters in the ground.

What a lovely thing to do! In March I usually put mine in pots with compost somewhere light and undercover and wait for them to sprout. You will then see which ones are viable. After the last frost usually mid May time you would plant them out in beds or larger pots. It’s important to support them (ie tie in to a bamboo cane so they don’t fall over in high winds. Otherwise leave them to it and they should flower beautifully. There are lots of how tos online Sarah Raven or farmer Gracy should have info/videos on what to do.

Place the tubers in a shallow container with good garden compost. The tubers should just be stirring on the compost. Keep in the dark for another three to six weeks and then you should see tiny red shoots appearing on the top of the dahlias. Once this happens move them out into the light watering very slightly. Depending on where you live and how cold the weather is you can put a shelter over them. Under a bench or table is ideal.

Once the first green leaves appear plant them in pots or the garden. Feed with fish blood and bone to get established. If you use good soil they should not need any further feeding. Protect from snails slugs and earwigs.

Thanks everyone.
@Figgysmum do you cover them up with mulch or something in the winter? I'd much prefer not having to dig them up & faff around with them :) We have clay soil if that makes a difference.

I do tend to throw a bit of mulch over but not all the time. They do take a little longer to come through than if you grow them on in the greenhouse but they just wait for the soil to warm up. I live in the northwest and get rotten weather but like I said, they have never let me down. Good luck.

It's not cold (within reason) that kills dahlias, it's wetness. In cold dry conditions they will generally survive a winter. Cold and wet - no. And it has been very wet.

Leave them where they are for now. Pot them up end of march.