If you haven’t done so already, tender bulbs should be dug soon. These tropical plants such as cannas, caladiums, dahlias, elephant ears, gladiolus and tuberous begonia will be killed by our cold winter temperatures if left outdoors.
Once the foliage has begun to turn yellow, or has been killed by a frost it can be cut back. The plants should be dug up within a few days of a frost to make sure rot-causing organisms don’t enter the bulbs. Care should be taken when digging plants to ensure they aren’t damaged as this creates entry points for pathogens. Try using a digging fork, which is less likely than a shovel to cause injury to the ‘bulbs’. After bulbs have been dug remove any excess soil on the bulbs and discard any damaged bulbs.
Most bulbs will need a curing, or drying, period before being stored for the winter. This can be as short as 1 to 3 days or as long as long as three weeks for plants like gladiolus and callas. While drying keep the bulbs out of direct sunlight, and in a well-ventilated area with temperatures around 60 to 70 degrees.
Before storing bulbs inspect them again for any signs of disease or insects. Discard or treat any bulbs that may have pest problems. It’s also a good idea to label what the bulbs so that you know what’s what come spring. Dried bulbs can be stored in 2 to 3 inch layers of peat moss, sand, vermiculite, saw dust or coconut coir in a well-ventilated container such as milk or bread crates or cardboard boxes. Try not to let bulbs touch one another while they are being stored, this will help prevent spread of rot between bulbs. For the most part bulbs should be stored in a cool area with temperatures around 40 to 50 degrees such as an unheated garage, an unfinished basement or a root cellar.
Periodically check your bulbs throughout the winter and remove any that appear to be rotting. Also check on the moisture levels. If bulbs are beginning to shrink and become wrinkled moisten the media they are being stored in with at spray bottle. Just make sure not to moisten them to much because that can lead to rot.