Dahlias, what to do?

Hi all,
For the first time this year I grew a lot of dahlias from seed, and they've all done really well.
Some of them are still doing well, while others now seem spent and need digging up.
Question is, what do I do with the tubers? Do you store them (if so how) and mark up what type/colour they were?
Or do you just leave them in the ground?
If you take them up and store them in the garage for example, when should you look to plant them next year?
Lots of questions I know.......
Thanks all.

 

I leave mine in the ground, but I have sandy well-drained soil that doesn't get waterlogged (or not for long anyway) and lower rainfall than some parts of the UK. In colder or very wet conditions (or wet then frozen) they're probably better lifted. Mine are often late to get going in spring (sometimes no sign of life until well into May) but there's plenty of other colour in the garden so I don't mind that the dahlias don't really get going with flowers until July or so.

I'm sure someone who lifts them for winter storage will be along soon with advice, but I think they need to be kept somewhere cool but frost-free (maybe packed in something like straw or newspaper?). I would definitely label each tuber because I know I would forget which was which. People often start them in pots in a greenhouse so that they can get to flowering size earlier than if they wait for outdoor conditions to be frost-free.

 

I have to lift them here. I've just done a few. It's too wet for them to survive outside.
The biggest problem is getting them well enough dried off that they don't stay wet over winter, and then just rot. after cutting back most of the foliage, I lay them on their side, slightly upside down so that any moisture can drain out of the stems rather than back into the tubers, and that's once I've removed all the soil from them. It can be tricky to get them really dried off before storing, so you may have to experiment with that, and also where you keep them. I only have a small growhouse, and I managed to keep one in there successfully last year, but the best place for mine is in the house - in a cupboard in the back hall, as it's the only place I can guarantee the protection. A porch or conservatory is also ideal.
The shed was far too wet, but I've rebuilt it this year, so I'm considering putting a couple of the seed grown ones in there, in a large plastic container, with some wood shavings, and enough of a gap in the lid for airflow.

As far as planting out again, just keep checking them in late winter/early spring, and when you see signs of growth, you can pot them up and give them more light, but you'll need to keep them protected until the temps suit for planting out. Ideally, don't have them too damp at that early stage - just enough to keep the compost moist.
It's not possible for anyone to accurately judge timing of them going out, because it depends entirely on where you are and what your climate is like. The ground temp is lower than the air temp too, so if they're going in the ground, you may have to wait longer than if they're potted.

 

I grow mine mainly in pots due to slugs, in winter the tubers are cleaned, inspected and dried off they then go into smaller pots and are covered in dry used compost and kept in the cold greenhouse.

 

Yes - slugs are a nightmare for them. All of mine are potted too @NigelJ.
I would struggle to have any compost dry enough for them. I find wood shavings quite good. Things like newspaper or card aren't any use because of having to ensure there's no remaining moisture from the dahlias to wet it, because then that doesn't dry off properly either, and just returns it to the tubers. Always a bit of a lottery here with them.

 

If I couldn't leave them in the ground I don't think I'd bother growing them. It sounds like a lot of faffing about.

 

It is a lot of faffing about but when they are in full flower they are worth it. I grow about 120 and lift and store them

 

Our dahlias were a gift from our younger son who died last year. We have had them now for 5 years and never lifted them. Each year the first frosts get them and they die back but again each year they come back better and better. They are still in full bloom and I take out the old heads and more flower buds develop. A constant reminder of our son with such vibrant colours each day. We are on heavy clay.

 

A lovely reminder of something very difficult @On the Levels , so any effort on your part would always be worthwhile. x

I don't grow a lot of them, and the slugs are certainly one of the biggest problems here. When I started growing them again a few years ago, after a very long break from it, I was reminded very quickly of why I'd stopped. If I had a large enough conservatory or greenhouse - and the latter would need to have a paved base to prevent dampness, I'd just move the pots into that, but I don't have either now. I had a friend who kept hers in the porch but I don't have that facility at this house.
They're easy enough from seed though, but you don't get the variety of shape and colour.

 

I have several large ones in containers but this year for the first time, none of them flowered. I assume inclement weather affected them. I am going to try storing them inthe shed year as I usually just leave them out all winter.

 

I tend to put dahlias and cannas in the same category, both survive most winters in the ground around here but flowering will always be later if you don't get them going earlier by lifting and dividing and growing away.
It also helps a bit with the slugs that seem to overwinter in the tubers and probably kill more than frost.

 

You have to be careful digging them up and I'd guess more tubers are lost because of damage, than anything else. I've grown them in pots and just put the pots in the shed, no removing the tubers and using a dry compost. I don't think a little bit of moisture hurts them at all unless they are already damaged but sodden soil will.
I've also cut some bracken and layed the tubers is a basket with it covering them. This works really well and is a great way to store them if they are dug up.

The ones I've left in the ground have normally be fine but I do add a thick layer of bracken over the top. I like bracken because it doesn't let all the water though and traps plenty of air in it for insulation. The trouble is that once I remove the cover in the spring, the new growth is just decimated by slugs and snails, to the point it's not worth it at all. It's one of the reason I have massively cut down on the ones I grew.

 

@On the Levels because they are of such special importance to you, would it be worth taking cuttings in spring so you can keep backups? It would be terrible if we had a nasty winter and you lost them.

 

Thank you @CarolineL I am hopeless at taking cuttings of anything but as I said each year his dahlias grow more and more and flower for longer. If we lose them then we still have other plants that he gave us over the years. So many other memories.

 

When they get back into growth @On the Levels , that's the ideal time for cuttings. You can usually just pull off a nice green bit off, and there'll be a 'heel' on it, which makes it easier for establishment. Those are easy to grow on. You can also lift and divide the tubers as they get bigger, and yours would certainly be that kind of size

It's wet cold that does for them. That's the problem we have here. It penetrates anything you'd cover them with too, and would actually make it worse as it would hold it all in. Been there and done that - too many times. The surrounding wet ground just means a plentiful supply of moisture to get into the tubers too. Lighter, sandier soil is completely different, and it's easier to cover and protect them in those conditions too, so frosts aren't as big a problem, except in properly cold areas where they stay for a week at a time. That's when it's important to protect them early enough - or lift them.