Dahlia tubers

[DareIask]

What do I do with them?!

I have 2 bags of tubers, 5 in each bag. I had planned to start them off in the greenhouse and then plant in the garden. How many do I put in each pot? Which size pot?!

Or should I just put them all in together?

Should I cut up the big ones?

Please help, wise gardeners x

My experience is that they can make use of all the space you can give them. If the pot is less than 30cm dia! Certainly only one to a pot

Don't cut up the big ones. The tuber needs to have "eyes" which is where the shoots come from and are often on the crown (the bit at the top which joins all the little storage tubers together). If you cut them up you risk planting just the storage tubers which have no eyes so will never flower. (Google Dahlia eyes if I haven't explained this very well)

You'd probably only want one in each pot as they grow massive underneath the soil. Each separate tuber need enough room to sit comfortably in the pot with the top of the crown visible above the soil. So that may be a 12 inch pot or slightly bigger.

They aren't frost hardy so yes you need to start them off in a coldframe or greenhouse until about May where they can live outside for the rest of the year. I've got 5 waiting to be potted up but I'm going to wait a few weeks to do this yet.

Thank you.. really helpful x

When do they start sprouting? I have a load in a box in the garage, should I take a look? I want to split them if possible, as they have been growing like mad.

I bought some dahlia topmix from the Range recently and have discovered that the stalk thingy is very soft, I suspect it is moldy. Does this mean it won't grow now?

Mine have started sprouting @MrsBertBibby

I went a bit dahlia doolally this year having not really been able to do anything like this while DS was baby/ small toddler.

Run out of windowsill space for now (waiting on greenhouse, this year I HOPE)

I'm waiting a few weeks yet to plant mine as well - they grow so big, and I'll have to keep them in until end of May as I'm up north. I need the space for all the other seedlings really - once again, I've bought far too many!

Oh no I just looked, and they are mouldy. How are you meant to stop that?

Back to the drawing board. Or rather, the seed packet!

Is it just surface mould which can be brushed off, or are the soft all through? Could you salvage any good bits by cutting off the mouldy bits?

I'll have to inspect further!

Also look into digging them up in autumn and storing them in a cardboard box in a garage over winter. There’s lots of videos on storing dahlia tubers online as well as how to separate them.

I’ve purchased two different varieties of tubers which I’ll be starting in the greenhouse upon arrival (from Farmer Gracy). I’ll plant into the border once the risk of the last frost is gone, hopefully around late April-May time.

@MrsBertBibby they should start “sprouting” around now, with the ‘eyes’ becoming quite pronounced. So if you want to split them then now is the time as it’s easier to see the eye-neck-tuber structure.