Storing Corms, Tubers, Bulbs, Rhizomes for Winter

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This year I’m trying a new method for storing my Alocasia corms (sometimes referred to as bulbs or tubers, but they are not true bulbs). I have seen Alocasia corms referred to as “tubers” in many garden reference and technical books, but for the purposes of this post, I’ll stick with corms as the term used for these Alocasia plants I am putting away for the winter months in Connecticut.

Bins Years Prior Used

For years, I stored the bases of underground parts from my elephant’s ears and canna lily plants in plastic bins with covers (air holes drilled in the covers) with peat. When I say “parts”, I’m referring to corms for the elephant’s ear (Alocasia and Colocasia) and rhizomes for the Canna Lily plants).

The peat (only a small amount below; used almost like a bed below the corms/rhizomes, and some peat lightly sprinkled over the tops of the corms and rhizomes) helped maintain a bit of moisture but kept the tubers in a dry but not too dry or too moist state.

However last year, some of my Alocasia corms had rot areas on them when I went to take them out in the spring to start growing again. They were too damp. Plastic bins will hold onto some moisture (versus a dry cardboard type box) but this problem of rot really had never occurred before. Since I want to make sure I am able to save these dramatic large Alocasia plants’ corms, I’m trying this new method this year.

Dug Up about a Week or few days prior

In last week’s post, I showed how I dug up the Alocasia plants from a huge cement planter, cutting off the foliage about 4-6″ from the top of the corm area, and laid them out in the sun for one day. Then I moved them to my basement in laundry baskets.

I also dug up a very large Alocasia plant prior to these, from a big tall patio planter, and laid out a huge corm with top part of the plant (stump like stem area) in a bin about a week before these above.

The ones in the laundry basket were still too damp when looking them over yesterday, so I laid them out on a table in my basement, and spread each corm on the table so they are not touching, and decided I will wait a few days longer before packing those up into boxes. I will leave these on a table another few days to air dry in my unheated basement.

However, I decided to pack up the others that were dug up prior from my gray patio planters. One of them is super large and heavy. It isn’t draining out any more water or moisture now, feels like it has dried enough, and there are no rot or damp areas on the corm area. It was placed in a bin in my basement about one week prior to those dug up from my cement planter so it and its side shoots have been drying longer.

In doing a bit of research, I’ve read Alocasia corms may be stored in newspaper and put in a cardboard box with air vents. I happen to have some boxes available and used a large sharp knife to make slits in the boxes around the perimeter of the cardboard boxes for the air vents.

Making air vents

I placed crumbled up newspaper sheets in the base of the cardboard box and used the original plastic mesh bags, which were around each corm when they were originally shipped to me. I placed individual corms into these mesh bags for those that would fit. My largest “stump” shown top right of this photo below is too large for any of the mesh bags I kept on hand.

Mesh Bag with Corm inside

I loosely wrapped a couple sheets of newspaper around this mesh bag once the corm was inside and put it in the box. I am careful to not have them stacked or touching too much with other corms handled the same method because if anything is damp, that moisture will transfer to any touching corms. However, these were all fairly dry and not moist. The idea is to not overpack any boxes and keep air around each.

Now for the larger Alocasia stump. I keep calling it that because it is so much larger, it is more like a stump size! This one I had to find a larger long box and I have no mesh bag for it. It also has a large green area (the top part of where it grew) still attached which is not wet at all when I decided to lay it into the long cardboard box. Again, I crumpled up newspaper below in the box, and then I used a paper bag to cover it like a blanket and close up the box. I did not tape the box closed, as air circulation is important. I just overlapped the covers and I also put vents in the sides like with the other cardboard box prior to laying it in there.

Largest Alocasia “stump”

The root area is dry with dry soil a bit still on it, the corm area is dry, and there is still green life on the top part but there is no dripping water coming out of it – it seems like it is dry enough. I labeled all the cardboard boxes with date and placed it in the usual corner of my unheated basement (by the door where it is like tucked in a corner, stays cool, dark, dry and it does not go below freezing here.)

I have read the optimum temperature for storing Alocasia corms is 40-45 degrees F. Again, my basement is unheated. The only time it may get warm in there is when we use a woodstove at the opposite end of our basement, which is only occasionally. It does not go below freezing (32 degrees F) so they will not freeze. They are kept in a consistent cool 50 degree range or a bit below that for the whole winter. I will check on these in one month by making a note on my calendar to go look at the corms in these cardboard boxes and seeing if they look good (no rot, no moisture, no wet newspaper).

Again, this is the first time I’m trying the cardboard box method for these. I also wish to note, canna lily rhizomes tend to not survive if they completely dry and wither up, so I don’t think I’ll use this method for those plants, only for my precious upright huge Alocasia plants’ corms. I’ve read more about how these are okay more on the dry side. Makes sense because when I purchased the corms about 3-4 years ago, they showed up in a card boad box, with the white mesh bag, shown above, and only the brownish corm with no plant at all attached.

Label the boxes
Corner in Basement

You see the big plastic bin near these two cardboard boxes, that was the bin I last used for my big red banana plant (stump), the Ensete, I had for over 10 years. It failed this year, so there’s nothing in that box right now. I also put a plastic shelf section below the boxes so it is not directly on the concrete floor which may lead to dampness on the bottom of the boxes.

Pic of corm inside a mesh bag

I just hope this works well this year and will keep you posted. Next up will be to dig up my canna lily plants from containers outdoors. Sometimes I don’t bother anymore with those as they may be easily grown from new plants next season, but it is always a great feeling to reuse and regrow plants to save money on purchasing new ones, but sometimes I run out of energy to keep digging up these things. Each year, I seem to do less storing because of the effort. Sunny days help!

Thank you for visiting,

Cathy Testa
Connecticut Planting Zone 6b
Date of Post: 10/18/2022

P.S. I also want to note, many references will indicate to let the plants get hit by frost first before storing underground parts like the corms or rhizomes, etc. because the freeze will induce dormancy to the plants, however, I often do this process just before a hard frost. The weathermen indicated frost may be happening this week. Wednesday’s forecast indicates about 34 degrees F overnight – so that is chilly!