[1] The term stratification can be traced back to at least 1664 in John Evelyn's Sylva, or A Discourse of Forest-Trees and the Propagation of Timber,[2] where seeds were layered (stratified) between layers of moist soil and the strata were exposed to winter conditions.
[citation needed] Cold stratification simulates the natural process by subjecting seed to a cool (ideally +1 to +3 °C [34 to 37 degrees Fahrenheit]) moist environment for a period one to three months.
Seeds are placed in a medium such as vermiculite, peat, or sand and refrigerated in a plastic bag or sealed container.
[1] Soaking the seeds in cold water for 6–12 hours before placing them in cold stratification can cut down on the amount of time needed for stratification, as the seed needs to absorb some moisture to enable the chemical changes that take place.
[citation needed] Use of a fungicide to moisten the stratifying vermiculite will help prevent fungal diseases.