This was my first year storing Banana plant(matured 8ft tall) in dark cold cellar. In june, i found stem got brown and mushy so chopped it to the corm. The corm is hard and size of a soccer ball….wondering if corm is alive ? and how do i bring it back to life indoors ?
Thank you for contacting Toronto Master Gardeners.
We wonder if this is not the first year that you have grown the Banana plant (Musa sp.) and perhaps you overwintered it in some other way previously. The month of June is very early for the aerial parts of the Banana plant to die down, and the mushy nature of the material suggests a disease or pest. Since the Banana is a tropical plant, the cold, dark cellar does not seem to be the best place to overwinter it.
We suggest that you carefully examine the rhizome, or corm, to check its general health with viable roots and ‘eyes’. If it is sound with roots and eyes, the rhizome can be cut into sections, each having an ‘eye’ and can be potted up in fresh soil to begin new plants or merely repot the rhizome in fresh potting soil as suggested in several of the links below. Careful inspection of the rhizome may indicate the presence of a fungus or an insect or other pest. We presume that your banana luxuriated in the sun outdoors during the summer months and any number of insects or other pests could have infected your plant.
The following links offer excellent information on the structure and function of the various parts of the banana plant: https://www.promusa.org/Morphology+of+banana+plant#Root_system
This link provides step-by-step instruction for cutting a rhizome and also for potting it up, and stresses the need for disinfecting your tools at each step of the way: https://homeguides.sfgate.com/cut-banana-rhizome-44834.html
https://www.wikihow.com/Grow-Banana-Trees-in-Containers has detailed instructions for planting and maintaining your banana.
Read more at Gardening Know How: Banana Plant Diseases And Pests: Troubleshooting Problems Affecting Bananas https://www.gardeningknowhow.com/edible/fruits/banana/problems-affecting-bananas.htm
Toronto Master Gardeners stress that any pesticides used must conform to the Ontario Pesticide law, please see the following website www.ontario.ca/page/pesticides-home-lawns-and-gardens
We wish you well in reinvigorating your Banana Plant.