Stratification

Stratification in a nutshell, is the process by which seeds are artificially exposed to conditions to encourage germination. Many seed species have a dormancy phase and more often than not will refuse to sprout until this dormancy is broken.

Cold Stratification

In nature the means of cold stratification is achieved by seeds falling from the parent plant and spending the winter being softened and weathered by the natural environment thus starting the germination process threw the softened shell.

We re-create this process by subjecting seeds to a cool (ideally +1° to +3°C) moist environment such as a refrigerator for 1 – 3 months. Seeds can be placed in stratification in a variety of mediums from potting mix to sand or even moist tissue paper and then sealed in a zip lock bag or plastic wrap. In some cases, a night in a cold-water bath prior to cold stratification can also speed the process up.

Warm and Cold Stratification 

For seeds that require warm & cold stratification, the process remains the same for the cold process, but additionally the seeds should first be stratified in a warm area followed by the cold period of treatment. The ideal temperature for a warm stratification is 15-20°C