Not all bulbs are created equal when it comes to storage. Have you ever noticed that some bulbs that you buy come in peat moss, others in wood chips, and still others in a mesh bag with nothing else? Needless to say, the bulb sellers would not include packing materials if there weren’t a good reason. Their reason is that some bulbs dry out more quickly than others and need help hanging on to their moisture content.
Next time you get bulbs like tulips, or daffodils or onions, take a good look and notice the papery covering. It is called a tunic and it helps the bulb conserve moisture while it is resting. Bulbs with tunics are called tunicate bulbs. Not all bulbs have tunics and they are much more likely to dry out or be injured. True lilies and fritillarias lack tunics and are known as imbricate bulbs. So, one look at a bulb and you know if protection from drying out and bruising are going to be an issue.
Actually, all bulbs and bulb like structures (like corms, tubers, and rhizomes) need some protection from drying out if they are going to be out of the ground for any length of time. But giving them that protection is a balancing act because you want to help them retain their moisture but you don’t want them to have so much moisture that they rot. All bulbs will loose some moisture as they rest so never store them in a plastic bag or container where the moisture cannot escape.
The most common storage problem is when you get your spring and summer blooming bulbs from their source and don’t have time to plant them for a few days, weeks, or months. Here are some suggestions for storing bulbs until planting time.
Most bulbs have a tunica and should be laid out in shallow pans or put in paper bags and put in a well ventilated, dry, cool room, a basement, garage, or refrigerator at 38-42o F. If placed in the refrigerator make sure they are far from fruits like apples or pears because the fruit gives off ethylene, a gas that can hurt flowering. Also make sure that the bulbs do not freeze or you will have a bag of mush.
True lilies and fritillaries like guinea hen flowers and crown imperials, do not have tunics and are vulnerable to drying out. They should be planted promptly to avoid injury or at the very least, planted first. If they are not in packing material place them in bags with wood shavings (from a pet store that sells hamsters) or sphagnum moss and put them in a cool room.
Some bulb like structures that are thought of as bulbs are also vulnerable to drying out. The corms of dogtooth violets, the tubers of dahlias and the rhizomes of cannas should be stored in wood shavings or peat moss to avoid drying out. Corms of gladiolas are tougher and more resistant to drying so they can be stored in paper bags. This whole group should be stored in a cool room or area.
These guidelines are for short term storage, not over a long period when drying out becomes more of a threat. Tender bulbs and bulb-like structures may be lifted and stored for winter but different methods are used to ensure that the bulbs do not dry out. See also my post on how to lift and store caladiums, and my post on overwintering dahlias.