Most "true" bulbs, such as daffodils and tulips, are winter hardy and do not need to be stored during the cold months. However, they do need to be stored if they are unplanted until you are ready to plant them in the fall. In addition, other bulb-like structures, such as tubers, rhizomes and corms, need to be stored if left unplanted and since many are tender, they may need to be stored during the winter months as well. While every kind of bulb is different, there are some general storing guidelines that are suitable for most.
Wait until after the foliage has yellowed to cut it off and then dig up your bulbs. Dig straight down in a circle around the base of your plant before pulling down on the handle of your shovel, garden fork or trowel. Larger bulbs like lilies are planted deeper (up to 8 inches deep) than small bulbs like crocuses (up to 4 inches deep). Tubers, rhizomes and corms are usually planted at the soil's surface or just beneath.
Shake off the excess dirt. Lay the bulbs out on newspaper in a dry location out of the sun to dry. Be aware that animals may damage or take your bulbs, so dry them in a safe location, such as in a spare room in your home. Most bulbs that are really corms (e.g., gladiolus, tigridia) need to dry--or cure--for 2-3 weeks before storing. In addition, some bulbs like cannas and dahlias should be washed first before drying.
Separate bulbs that are actually corms. Separate the small cormels growing on the old corm and throw the old corm (one on top) out.
Place the bulbs in a labeled, open container with some vermiculite or peat moss. Corms can be stored by themselves in paper bags. For tubers and true bulbs, add a bit of water so the soil is just slight moist. Store in a cool, dry location, that is generally between 40 and 50 degrees F, such as a garage, attic or crawl space.
Check on your bulbs every couple of weeks. Throw out rotting corms and true bulbs. Rhizomes and tubers can be cut if part of it is rotting. Add moisture to the soil if you notice they bulbs are drying up, especially for tubers and true bulbs.