Monday, November 7, 2011

Storing Tender Bulbs

MG Mary Crooks Dahlias
The newscolumn this week has an item about storing tender bulbs.  Here's an excerpt:

The term "tender bulb" refers to plants which have fleshy storage structures (bulbs, corms, tubers, and roots) which are killed by our cold winters if not brought indoors. Special protection, such as digging and bringing the fleshy storage structure into a warmer area for storage through the winter months is required.
MG Mary Crooks Dahlias
I dug my tender bulbs this weekend: cannas, glads, and dahlias. So did Mary Crooks. Her dahlias look much better’n mine, so I used her pictures. Here are some fact sheets describing how to store them for the winter. For Dahlias, from Colorado State University:
Place the tubers upside down in a dry airy space for about two weeks. This allows moisture to drain out of stems. The tubers need to be completely dry before they are stored for the winter. Next store the tubers in trays of dry sand or peat moss in a cool, dry cellar or storage area at about 40 to 45 degrees F. Never store at a much higher temperature, as dahlia tubers will dry out and shrivel rapidly.

Another method of storing includes placing tubers in a heavy-grade, black plastic bag without additional packing material. Then seal the bag. This will prevent the tubers from dehydrating. Keep the tubers in a frost-free area. The danger exists, however, that they will sweat and rot.

Inspect the tubers every few weeks during the winter to check for disease or shriveling. Cut off any diseased parts and, if the tubers have shriveled, place them in a bucket of water overnight to plump them up. Allow them to dry thoroughly before returning them to storage.

Glads and Canna's from Eckhart Garden
For Gladioli, from the University of Missouri:

After digging, wash off soil that adheres to the corm and roots. Cut the tops to within one-half inch of the corm. Corms can be left outdoors in the sun for a day or two if the temperatures are mild, and then spread out in a light, airy place to cure. They are cured to get the surplus moisture out of the husks and corms as quickly as possible to prevent storage rots. After two to three weeks of drying, remove the old corm from the base. Sort the corms and cormels according to size. The small cormels can be saved and planted the following year, but remember it will take two to three years to produce a blooming-size corm from them.


Corms should be stored during the winter at a temperature of 35 to 45 degrees Fahrenheit in a well-ventilated area. Airy containers such as loose-weave baskets, mesh bags or old nylon stockings make good containers that may be hung out of the way.
For Cannas, from the University of New Hampshire:

For winter storage they are treated much the same as dahlias. The rhizomes are dug after the frost kills the tops, they are dried in the sun for a day, clinging dirt is gently removed, and they are stored in a cool, moderately dry place (between 40 and 50 degrees Fahrenheit). Cannas should be packed in dry vermiculite, peat moss or rice/peanut/buckwheat/cocoa hulls.

One of the things I learned recently reading the University of Maryland's Growit Eatit blog, is that dahlia tubers are edible.  There's even a grower, food historian, and Mother Earth News Contributing Editor breeding cultivars that produce tubers that taste good.

If you have any procedures of your own to add, use the comments section.

UPDATE: 11/7/11 5:10 p.m. - Erica Smith of the Growit Eatit Blog shares her experience eating dahlia tubers.


  1. Hi Ray - thanks for the shout-out, and I just linked back to this very timely post in my new Grow It Eat It update where I actually eat the dahlias!

  2. Gotta investigate the yacon. Sounds yummy. I'll probably try one of my dahlia tubers, too, since you've led the way. Oh - we grow the Fish Pepper, too. I love the weird leaf variegation - splotchy, not symmetrical. Cheers.