Hi all! I spent days dividing and storing my tubers last month. I’m trying a few different methods this year to see what works best, including storing a few tubers of the same kind together in plastic bags with vermiculite. On those, I already noticed some were getting mildewy:( so I took those out and wiped clean with bleach. I already opened all the other bags that seemed at all damp inside to ensure air flow. I am going to re-store the ones that were moldy in pine shavings and paper bags but wondering if anyone else has tips for preventing mold on pre-divided tubers? I want these babies to make it to spring! Thanks!
by willaaak
11 Comments
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some of mine are moldy I just have them in the basement. Idk what I’m doing really, but last year one of my moldy tubers was fine. maybe these guys will be tougher than we think. I am going to do my best and let what will be, be and maybe I’ll get it more right next year lol.
Were the bags fully closed? If so that’s probably your problem. I’d be worried that you’re going from one extreme to the other now.
Couple questions. How dry were the tubers when you stored them? It looks like the vermiculite is sticking to the tubers, which makes me think they’re damp. I would try a more coarse vermiculite as well, if you can find some to try. What the temp where you’re storing them? Already asked by someone else, but make sure the bags are open. Honestly, storing tubers in vermiculite is great and works super well for me, but I’d switch to a different container, something like a little plastic tub for shoes. I use tubs I get from Ikea and they work super well. I drill a hole in each end of the tub, near the lid.
Like you, I’m trying some different methods this fall. I found a free wine fridge, so I’m saran wrapping some extras. I’m leaving a few in dirt (but out of the rain), storing some in paper grocery bags, storing a majority in vermiculite and I was shipped some mystery tubers in peat moss, so I’ll be leaving them in the usps box and putting those in the fridge in my garage.
This seems to be a learning process for everyone since conditions vary so wildly, but I truly think tubers are super hardy if you can figure out what works best for ya 🙂
You will want to check on the ones in paper….a lot. Paper wicks moisture away.
Slightly damp peat moss, frequent check for dehydration,light water spritzing, open containers and this year I will try dusting some tubers with sulfur before storing Any suggestions or thoughts about the sulfur dusting?
I did ziplocks last year and some got moldy. I had one set in a paper bag and it didn’t get moldy so all of mine are in paper bags (with coarse vermiculite) this year. Then in a big plastic tote. I am in the PNW so the humidity outside in my unheated exterior building is pretty damp so I am more worried about mold than drying out.
Dark airy space loosely covered in a bit of earth and then newspaper on top loosely. Air flow essential or they rot
How do you know if the media you are storing the dahlias in is not contaminated? That is hard to know. I wrap individual dahlias in plastic, I mean wrap! If that tuber has mold on it come March, the tuber had a problem. I have wrapped over 400 one year and only had a 4.5% loss in march. I have an old fire place in my basement, zone 4B. I make it a root cellar by covering it with 5 inch styrofoam insulation. There is no flue but covered on top of the stack with steel. 45 degrees and 45% humidity on 12/05/2025.
I put mine in the garage in open tubs and plant pots, nestled in old dry potting soil. Every single variety had good tubers and have started sprouting now (I’m in Australia, just planted recently as we are at the start of summer).
Does bleach, harm them?
I checked mine also and a few has mildew 🙁