Winter tuber storage

calico20hill · 2023-12-31T00:08:04+00:00

I just did a quick check on my tubers and I am encouraged. No whiff of mold, no wrinkles, and these were small tubers that would not necessarily store well...

Veryzer

MissyWeitzel That's a very compelling option for those of us in bone cold climates who lack a root cellar. And this way I wouldn't have to tell my wife that we'll only be short on refrigerator space for five months. Thanks!

katyaker

On this rainy weekend, I am working on plans for a new dahlia storage and work space building. It is going to be approximately 24' x 24', probably built with double stud 2 x 4 walls (which allows for extra insulation and no thermal bridging) and have two separate rooms - one cold room (40 degrees)for storing tubers over the winter and one warm room (60 - 70 degrees) for dividing and drying cut tubers and also to be used in spring for taking cuttings. It will also have a lean-to type overhang where I can pull up in my golf cart with a loaded utility cart, unload tubers and wash them, then store them on racks undercover to drip off excess water before being brought inside the warm room to be divided and dried, then stored in the cold room.

My current storage room is already too small and somehow I managed to purchase more than 100 new varieties this year. Definitely will not have enough space to store them all in my 7' x 11' room in my barn.

Many of the boxes this year contain multiple varieties, which is inconvenient when someone wants a tuber, which is always on the bottom!

I live in NW Washington State, zone 8b (I think it is still 8b anyway). The temperature this year has dipped into single digits for more than a week. Normally our low temp is closer to low to mid 20s.

Does anyone have any suggestions/recommendations for such a building? I hate to spend the time and money to build this structure only to find out later, "I wish I had thought of that, or done something differently." What is the best temp and humidity for the cold side for winter storage?

Dahlia53

Hi @katyaker; I live in zone 8b - those ridiculous zone categories make me laugh because lately, in most of our winters it goes down to single digits at least once for at least 5 days or more - making us a zone 6 during those temps. I have stored my dahlias in an unheated storage unit for many years. If I go get all the tubs and bring them inside, for the worst of it, they make it. But I've lost about 2/3 of them the last two years I didn't fetch the tubs (one year, due to snow, couldn't drive to get them).

Last year I kept my tubers in giant tubs in a friend's unheated basement in wood shavings, layered with cardboard between the layers. That worked out good. I had few losses.

I tried an experiment as well last winter because the year before that I accidentally forgot a few very small tuber clumps in a small cardboard box - there was no sawdust or shavings in the box - just the small clumps and even a few singles.. I found them the following spring in the storage unit. They had shriveled, but I reconstituted them to where at least half of them sprouted! So I got hold of one of those styrofoam coolers that are used to ship medical things, I saran wrapped some backup single tubers in case of losses, put them in a cardboard box and put that in the small cooler. I had some losses but not many. I knew cardboard would be a better insulator than the plastic tubs I'd been using.
So my thoughts are that humidity is ok but It's wet and rot plus freezing temperatures that turn tubers to mush. That made me think about whether I want to store them in plastic at all. (If you have rodents, you have to, since rats, voles, and mice all love to eat dahlia tubers.)

Looks like you have a very nice setup; that's a huge storage room you're building! Would love to see pics when you're done putting them to bed this fall.

Teddahlia

Cardboard is not a good storage container for dahlias here in the PNW. Our big enemy in the winter is high humidity and cardboard attracts moisture. Humidity differs from wet in that dahlias like some humidity to stay plump but can rot in wet.
90% of dahlia storage issues are genetic. People try to store tubers that do not store well. Yes, some excellent technique can work sometimes to store the poor tuber keepers. Good tuber keepers are so easy to store that I often divide them and throw them 10 at a time into a plastic t shirt bag and put the bags into a large plastic crate. No vermiculite, no wood shavings, nothing at all. The easy keeping varieties do not rot and are in excellent condition in the spring.
Poor keeping varieties benefit from a whole bunch of procedures but even when everything is done right , many or most of them rot.
Dahlias freeze when temps are about 30F for an extended period. If you have enough insulation around the dahlia containers in an unheated storage shed, they will not freeze. I am talking about a foot or two of insulation. Ten or twenty blankets may do it too, especially old quilts. Remember water pipes do not freeze as they are two feet under the ground.

calico20hill

I only have 5 winter's experience at our new place but tuber storage has worked out fine in our big metal garage. My husband built me a "tuber vault" along an outside wall. He lined it with insulation and wallboard and put in shelves. The inside door is covered in wall board as well. I store the plastic bins on shelves in it. I do pack the tubers in wood chips and use cinnamon liberally. I also mist the wood chips lightly with water and re-mist them a couple of times in the winter when I do a tuber check. If the tubers were in good shape when they went into storage they are generally in good shape when they come out. The immature ones I try to save. not so much. But probably nothing short of keeping them growing under lights would save them.

Location, PNW approximatly 30 miles north of Portland, Oregon and 20 miles south of Longview, WA, on the Oregon side of the Columbia River.

Spoo

Hi katyaker, no doubt you have your building going by now, but just wanted to put in a plug for Coolbot. We built 2 small coolers (6x8 and 7x9) in an old wooden "carriage house" on our farm in 2018, and have been very happy with how it went. We accessed all the building materials at the local box stores, according to the directions the Coolbot people share. It maintains at 44 degrees in the winter, except when it gets really cold outside, like now (28degrees) , we have to open the cooler doors to the main part of the building (overall 16' x 18') and turn the heat on in there slightly to keep it from freezing. Humidity is about 85%. We check it twice, morning and night, though you could get a phone notification if you wanted. The coolers hold tubers from 1200 plants. We use the space all year round, to chill bouquets at 38 degrees, overflow refrigerator when we have guests, store produce until we can preserve it. It's been great! Have also used one of the coolers to dry flowers, with a humidifier added. I'm sure you have found lots of uses too, you won't be sorry!

Teddahlia

Washed the last batch of tubers and need to divide them.

KitCMC

Teddahlia Woo-Hoo! That is such a great feeling, and I only grow a couple hundred.

Teddahlia

And in the last batch of tuber clumps I found the two missing clumps of one that we really need. I did "cheat" and we now have about 100 clumps of excess stock and will store them with their dirt on and if we do need them I will divide them in the spring. Some good ones in there but I have no more "dividing energy" and need to focus on dividing the last 200 clumps and then the final sorting. Washing in the 42 degree weather was not too bad. I washed myself with the hose when I finished. One problem one does not anticipate is how do you get back into the house when you are dripping muddy water from your recent body washing. In the past I have left a very dirty trail of muddy water. Now I strategically remove many items of clothing while outside. I will not go into further detail.

Bessie

Teddahlia I think "ENERGY" is what has defined my behavior the past few months. Between all the colds and flu bugs going around, coupled around a lack of process, repeatability, and indecision in the dahlia harvest, I have not been very productive! I have the luxury in my climate of procrastinating on digging and dividing, and I take advantage of that. I do however really enjoy reading posts on this forum. ### 🙂

Yesterday I potted up the tiny(smaller than a dime) tubers I dug a few weeks ago. A few of those may represent the only genetic material I'll have of some of my best seedlings for 2024, thanks to gophers eating up tubers, and me overwatering when I relocated the clumps.

My winter storage of tubers is storing whole unwashed clumps in cardboard boxes (think Costco size). I cover the clumps with brown wrapping paper that comes with online orders. I check once a week at this point and spray mist the paper if the humidity drops below 65%. The storage is in a walk in, unheated space under my house that stays in the low fifties temperature wise. I purchased a temperature/humidifier monitor that has three probes a few months ago. One probe is now with the stored tubers and one probe is with the tiny potted up tubers to ensure they don't get too hot on the heat mat.

Teddahlia

California dahlia growers because they have no cool area to store tubers, do not dig their tubers until about February or March. They then dig and divide and often plant again right away. Gophers upset this tried and true method as they can eat them any time of the year.

SteveM

Teddahlia storing tubers in the ground can cause other considerations. My father swore that tubers obtained from Southern growers (like myself) took longer to sprout compared to tubers procured from Northern growers. A biologist told him it was because the tubers needed to convert the starches to sugars before they could sprout and exposure to cold temperatures was one factor that did this conversion in tubers. This was in the 1980's when I was considering selling tubers. I decided on cut flowers instead so never researched it further to determine the necessary time and temperatures needed or other factors (like length of storage) that would also affect the tuber sugar content. There is probably research that has been done since then that provides the answers and is something I will have to study if I ever sell tubers.

Bessie

SteveM the sugar theory of tubers waking up reminded me of a very old post I made regarding a research study that showed 1% or 8% sucrose was effective in breaking seed potato dormancy. However, I actually think warm temperatures contributes the most to breaking dormancy.
https://forum.dahliaaddict.com/d/7-general-dahlia-chat-2023/460

Teddahlia

Getting close to the end of the tuber dividing. I have not stabbed or cut myself in about a week. The worst stab this year was to the "meat" of my left thumb. The tips of the bonsai scissors are sharp and the wound was a clean jab. It was sore for a few days but no infection. I wish an old friend whom I have not seen for long time would grab my hand to shake it. My "tuber dividing grip" is quite impressive.

DarcyD

Teddahlia
I bought some of those chefs gloves. But of course haven’t worn them because I like to feel what I’m working with, well and they’re annoying. 🤦🏻‍♀️

KitCMC

DarcyD I’ve considered of getting some type of glove for my non-dominant hand. Sounds like they’re awkward?

Krista

I purchased these for when I have folks over to split tubers — I can’t live with the possibility of sending someone to the hospital from my own house. Admittedly, I don’t wear them myself mostly because they’re one more thing to disinfect between clumps, and when cold and wet they’re not very comfortable.

katyaker

After a trip to the emergency room last year to have my little finger stitched up and having 3 weeks of down time, I found these gloves at Coastal Farm and Ranch: https://classicrope.com/Details/High%20Performance%20Roping%20Glove/CPCGLOVEWHXL

They come in a large range of sizes and you get 6 gloves for around $25. No more cuts on my non-dominant hand. They are a little slippery which is why I only use them on my non-dominant hand, which is the one I cut the most often.

I also found these little cut-resistant finger tip protectors: https://www.amazon.com/Resistant-Protector-Protectors-Protection-Sculpture/dp/B0937LZK25/ref=sr_1_6?sr=8-6
Haven't tried them yet. Hoping they will work on my dominant hand thumb, which is where I get the second most cuts while dividing.

KitCMC

katyaker thanks for sharing!

Teddahlia

Are you using bonsai scissors or chainsaws to divide the tubers? Oops, I meant to say knives not chainsaw. 😳Allen of Allen's Dahlias uses an electric bandsaw that would slice off entire fingers or hands.

katyaker

Teddahlia I use Felco's, curved stainless steel snips and a razor sharp utility knife. The utility knife did me in last year. Just one little slip. I do have a friend who divides his tubers with a bandsaw. He has been doing it for decades and still has all his fingers.

SteveM

One year I broke my arm just before digging season and couldn't hold tubers in my left hand to divide them. I bought an electric jigsaw and held the tubers between my thighs to divide them. I divided 2000+ clumps this way and was very fortunate to not have a single slip. I don't recommend this method.

Juliarugula

SteveM that sounds terrifying. 😳

KitCMC

SteveM Juliarugula it really does

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