The question I get asked the most about dahlias is "How do I dig, divide, and store my tubers for the winter?" Dahlia tubers will be destroyed if they are left in the ground during the winter here in Westchester County NY, so they need to be dug up each year. After the first frost, the dahlia plants will turn black and the leaves will collapse against the stems. Once this occurs, cut the plant down to about 4 inches above the ground and attach an identifying tag to the short stalk. Use a shovel or digging fork to carefully loosen the soil around the tuber clump and gently lift it from the ground. Wash all excess soil from the clump using a garden hose being careful not to damage the thin protective skin of the tubers. Let the clumps dry overnight in the garage allowing the protective skin around the tubers to harden or "cure." This will help maintain the proper amount of moisture in the tuber during its long winter’s nap.

Dahlia clumps should be divided and separated into individual tubers, using a knife or a long nosed clipper. Before dividing, remove any damaged tubers and all hair roots. Each tuber must have an eye. The eyes are located near the stem of the clump. I usually first divide the clump in half, making it easier to see the eyes more clearly and divide the individual tubers. Remember that you must remove part of the stem with an eye for that tuber to be a viable tuber. That being said, on occasion I have divided a tuber without a visible eye on the stem and an eye did appear during the over-winter storage period. Next, use an indelible marker such as a Sharpie to label each tuber. Place them in a one-gallon Ziploc bag filled with one-third vermiculite and 2 tablespoons of a fungicidal powder. (You can put a number of tubers of the same variety in one bag.) Shake the contents around in a Shake ‘n Bake fashion to get the fungicidal powder to coat the tubers. I then write the variety’s name on the outside of the bag and place the bags in a cardboard box that’s lined with 12-15 sheets of newspaper for insulation. The bags are left open in the box and the box is closed and placed in my attic for winter storage. Tubers do best when maintained at a temperature between 38-50 degrees so it’s critical to find the right area in you home, whether it’s the attic, garage, or an unfinished basement.

I usually check on my tubers once a month during the winter to ensure they aren’t rotting. If you do notice a tuber rotting, remove it from the bag so that the fungus doesn’t infect the remainder of the tubers. These steps will result in a viable supply of healthy tubers for the next growing season.

Happy gardening,
Ed Bonci
MG 2006

Wonderful article thank you

Thanks, cherie

Do you know anyone with a garage who could store a box or two for you?

only people i know that have garages keep them heated so they can use them in the winter. go figure...

After the tubers are dug up, cleaned and dried, are they suppose to feel a little tender to the touch?? Not mushy but just not hard like when they are ready to be planted in the spring?

If the frige is a frost free, it will dry out the tuber. My plastic bags are kept closed, BUT, I do keep an eye open for condensation inside the bag. When that happens, I put a dry paper towel inside for a few days to absorb the excess moisture, removing it later. If available, I will use those little bags of desiccant.

ML

I plan on getting a fridge in my basement to store the tubers because the temp fluctuations in my garage worry me. I have mine in bags of vermiculite. Do you have any idea if vacuum sealing those bags will help with shriveling/condensation?

For the record, I'm going to try Ed's method at the top of this thread for a few stray tubers this year. The majority of others will go in Saran wrap.