Abstract: A device and method for storing, curing, drying hay and other fibrous plant materials which includes a flexible water impermeable bag, as injection means at one end and an adjustable vent at the opposite end, and preferably spacer means between stacks of baled materials. The bales are progressively loaded at one end as the bag is unrolled and extended progressively laterally for additional bales. After loading, the gas injection and vent means are connected at ends of the bag and are adjusted to generate a back pressure within the bag to partially inflate it. The flowrate of gas or air is adjusted to maintain the temperature within the bales within an optimal range, preferably between ambient temperature and 120 degrees Fahrenheit enabling beneficial curing until sufficient moisture has been removed to prevent mold growth.