I stored some lily bulbs and dahlia tubers over the winter. Some feel reasonably firm, others feel spongy. Should I assume the spongy ones are dead and just plant the firm ones?
Lily bulbs can survive outdoors throughout the winter and don’t need to be dug up and stored inside.
As for dahlias, their tuber storage requirements are typical of all bulbs, but with the additional recommendation that they be stored at a temperature of 5 to 7 degrees C (41 to 45 degrees F). Bulbs should be allowed to dry out for at least 10 days in an area with good air flow, and should not be stored if damaged or diseased. Soil should be removed from the bulbs, and they should be placed so as to not touch (to prevent rotting) in open trays, and surrounded with a dry medium such as peat moss (some people use wood shavings or newspaper).
Bulbs that are soft or mushy when taken out of storage should be discarded. To be healthy, they should appear similar to when they were first purchased for planting.