Pre-treating seeds (cold stratification) is a simple measure you can take which will break a seed's dormancy causing the seed to be more ready to germinate. By subjecting the seeds to this pre-treatment you are really only providing them with the effect that mother nature would have had on the seeds had they been left to their natural course. However by applying the pre-treatment yourself in a controlled environment such as your refrigerator, you are speeding the process up and are better able to control and diminish factors detrimental to a seed's survival had it been left to make it on its own in the wild. By cold stratifying the seeds you are able to affect the time frame under which the seeds will germinate. By not cold stratifying the seeds you will have to be content to accept nature's timeframe.