Storing Summer Bulbs, Corms, Rhizomes, and Tubers

I live in a climate where tender bulbs, corms, rhizomes, and tubers do well for summer color but don't survive our chilly winters if left outdoors.  So, each spring, I plant them and each fall I dig them up, bring them in and store them for the winter.  I love the glorious summer blooms of gladiolus, dahlias, cannas, calla lilies, and pineapple lilies, so I'm willing to do the extra work.

It's a pretty easy process, really.  After the fall frosts kill the foliage, but before it gets cold enough to freeze the part of the plant that is below the soil surface, I dig them.  I knock off as much of the soil as possible.  In a dry year, that might be all I need to do.  In a wet year, when our heavy clay soil tends to cling to everything, I toss them in a wheelbarrow, fill it with water, and wash the soil off. 

Once the soil is off, I put the bulbs, corms, rhizomes, or tubers (for ease of writing, from here on, I'll simply refer to them all as "bulbs") in a bucket filled with a 10% bleach solution (1 cup bleach to 10 cups water), and let them soak for 15 minutes or so.  The bleach solution kills any bacteria, fungi and molds the bulbs might have picked up from the soil and  helps preserve them for the next year. 

After the bleach soak, I lay the bulbs out in single layers, on a piece of newspaper and let them dry well.  Once they are fully dry, they are ready to put in their winter beds.  I've found that they overwinter best when stored in peat moss. but sawdust works, too.  They need to be stored in a container that allows air to circulate and doesn't collect moisture.  A paper box will do, but I've had the best luck using a plastic bin that I've drilled air holes into the ends.  The plastic doesn't pick up moisture from the cool air temperatures like carboard can.  It also lasts from year to year, so I don't have to spend time each fall searching for a storage container.

Pack the bin, starting with a layer of peat moss, then a single layer of bulbs, top it with peat moss, place a single layer of newspaper over the top of the peat moss, top the newspaper with more peat moss, add another single layer of bulbs,  and just keep repeating that process until either all the bulbs are stored or until the container is full. 

I use the newspapers to separate the layers because  that way I can keep the various bulbs separated into varieities.  It also makes it easier to  periodically check how things are looking over the winter storage time.

The filled container is then stored in a cold, dark place where it will not freeze.  I store mine under the shelves in our cold storage room, where the temperature stays about 40 degrees all the time, but a temp anywhere between 40 and 50 degrees is fine.

It is important to check your stored bulbs at least monthly during the storage period for any signs of rot or over-drying.  If they appear to be overdrying, you can moisten the peat moss very, very slightly, and make sure that each of the bulbs is fully covered with peat moss.  Over-drying, also known as dessication, can occur if storage temperatures are too high, so if possible, move them to a cooler location.

If signs of rot begin to appear, if it is only a small area, you might be able to trim the bad area off and salvage the rest of the bulb.  Allow the trimmed edge to dry slightly and then store the salvaged bulb separate from the unaffected bulbs.  Do not allow any bulbs showing signs of rot to stay in the bin with healthy bulbs, as the rot can quickly spread and destroy your whole store of bulbs.