Winter Storage of Tender Bulbs

Plants with tender underground structures such as tubers, corms and bulbs are grown as annuals in Minnesota. We must dig these underground structures in the fall and store them over the winter or they would be killed by the winter temperatures.

Digging up the bulbs

• Dig up your tender bulbs as soon as the foliage dries up or is killed by a frost.
• Exceptions to this rule are tuberous begonias and the Peruvian daffodils. Dig tubers of these two plants BEFORE the first killing frost.
• Use a spade type shovel or fork to dig several inches away from the base of the plant so the bulb will not be damaged. Any damage that occurs to the bulb such as nicking the skin will invite disease.

Cleaning and Drying

• Wash all of the soil off the bulbs before storage with water or wait until the soil has dried and gently shake it off.
• Dry the bulbs that may take three days to three weeks. The average temperature to dry bulbs is 60-70 degrees F. The area should be dry and well-ventilated.
• After the bulbs is dry, dust or spray them with an insecticide/fungicide mix. Linders recommends a dusting with thiram for fungus control and Malathion for insect control. A Bulb dust is available.

Fall Storage

• Bulbs may be stored in perlite, vermiculite, dry peat moss, sand, or in a paper bag. The bulbs must not dry out to the point of dying, but must be able to breathe.
• Store the bulbs in a dry, cool place such as the basement with temperatures of 40-55 degrees. It is important that the bulbs DO NOT FREEZE.
• Check bulbs occasionally during the winter months for shrinkage or spoilage.