How to Dig Dahlias for Storage
Learn how to dig dahlias for storage so you can have plump, healthy tubers to replant in the spring!
Frost covered dahlias are stunning…
Digging Dahlias
When should you dig your dahlias for the best storage? There is some discussion on the best time to dig your dahlia tubers for storage. Some growers recommend waiting until your dahlias have turned completely black after frost. Others would argue that they have not seen any significant advantage to this approach. I have tried both ways and would agree, I didn't notice a difference. That being said, my mind always tells me to wait until they turn black. When the plants look dead, it's much easier to cut them down!
To begin the process of digging up your beautiful tubers you'll want to have a few tools. I like to use a pitchfork, a pair of clippers, and some gardening gloves. Snip the top of the plant off about 6 inches above the ground. This will leave you with a nice handle to help pull your clump of tubers out of their bed of dirt. Position your pitchfork about 12 inches away from the stem to ensure you don't stab any of the hidden tubers. Gently slide your pitchfork into the dirt at an angle, and begin to lift your dahlia clump up out of the bed.
Freshly dug clump of tubers.
Now, if you're lucky you'll have beautifully loose soil that will fall away from your tubers as soon as you free their roots. As for me, I usually get a lump of clay that clings to everything, including the pitchfork. If this sounds familiar, don't worry; just be gentle. Loosen as much of the dirt as you can, the rest will be washed off.
My lovely Missouri clay dirt.
A Lesson Learned
Once you have your tubers out of the ground, what do you do next? Some people prefer to store their tubers in clumps, without washing or dividing them. In this case you want to leave a little dirt on the tubers to help keep them from drying out. I don't have a place large enough or warm enough to do this, so I choose to wash and divide my tubers right away. This way I can condense them into a couple of plastic totes that take much less room. CAUTION: Do NOT go all out digging and washing all of your tubers, then leave them out to dry when there is a frosty night in the forecast. Wondering how I know?
Last year I had about 150 dahlia plants in the ground. My daughters and I worked our tails off, digging, washing, and transporting to the unheated greenhouse to dry. Then we had a dip in temperatures, and as a quick fix I threw an electric heater in the greenhouse to ward off a freeze. This *might* have worked, but sometime in the middle of the night that little heater burned out and died. Can you imagine how heartbroken I was the next day? Yes, I shed a few tears.
A week later when I had built up enough courage to assess the damage, I was hopeful that at least a few of them might have survived the cold. I stored away anything I thought might have a chance. Low and behold, I ended up with about 100 tubers the next spring! Some dahlias are definitely tougher than others. As with any hard learned lesson, I'm re-evaluating how to dig dahlias for storage with a smaller margin of error!
This year, I have a better plan. If the weather is cold, I'll dig 5-10 dahlias at a time, wash them, and let them dry. If I need to, I will bring them in the house to finish drying. This way I'm not overwhelmed with hundreds of dahlia tubers to find a place for. The rest will be safe in the ground for awhile (they must be dug up before the ground freezes.). Then I'll divide the clumps, and store them safely away.
How to Wash the Tubers for Storage
How do I wash my tubers? I don't have anything fancy, just an old plastic milk crate. It allows the water and dirt to fall through, but not the tubers. I place my clump of tubers on the "wash stand", and start spraying the dirt off. You want to use enough force to get the dirt moving, but not enough that you'll peel the skin off your tubers. Once clean, you are ready to start dividing your clumps into individual tubers. You're halfway through learning how to dig dahlias for storage!
Washing a clump of tubers on a milk crate.
Clean tubers drying in the greenhouse.
Dividing Dahlia Tubers for Storage
Diving dahlia tubers can be a little intimidating. You've worked so hard cultivating these beautiful plants, you don't want to risk messing them up! Don't worry, it's not as hard as it seems. You want to look for the little nubbins that will be the "eyes". This is where the tuber will sprout next spring. As long as a tuber has 1 eye, you can detach it from the mother tuber (this year's tuber). You can be as nitpicky as you like. If you want to really grow your numbers, you can split off as many tubers with eyes as you can. This can get tedious, but so worth the effort! If you're not concerned with numbers, you can just split your clump down to smaller "clumps" so they are easier to store and the tubers won't break off as you move them around.
You do need to be careful not to break the necks of the tubers. The neck is the skinny part next to the place the tubers are connected. If you break the neck, there's no way to transfer those stored nutrients, and no way for the eyes to ever sprout. However sad it may be, do not be tempted to give a tuber with a broken neck a chance. It will more than likely rot in storage, which in turn could cause your healthy tubers to rot as well.
Storing Dahlia Tubers
Make sure you allow your tubers sufficient time to dry. If not, you are increasing your chances of mold and rot during storage. Give your tubers several days to fully dry.
Once my tubers are divided and dry, I like to write on the actual tuber with the name of the dahlia variety. Make sure to use a permanent marker. Since I am short on space, I place all of my varieties in boxes together. Then I use pine shavings (do not use cedar) to line the bottom of the box, and start layering my tubers. Pine shavings, 1 layer of tubers, a layer of pine shavings, and so on. You do not want your tubers to be touching in the event any of them develop mold or begin to rot.
Once your box is full, put a lid on it, label it, and store it somewhere that will stay cool but will not freeze. For me this is in the side closets of my upstairs (I live in a ground contact home). We heat downstairs with a wood stove, but only have 1 small electric heater upstairs for the really cold nights. Another great place would be a garage or a basement.
During Storage
This is my method for how to dig dahlias for storage. In the world of growing, there will always be new lessons to learn. There will always be new ideas on how to improve a system. When I follow my own outline for how to dig dahlias for storage, it works well. But when Mother Nature inevitably throws her wrenches into my plans, my problems arise when I don't adjust well. We must always be ready to "go with the flow", and be flexible in our plans when it comes to nature.
Additional Resources
Check out these links to trusted sites for more information on dahlias: