Karma (or cause) has a kind of unique ability. Although our naked eyes cannot see how rice seeds will germinate, the seeds do have within themselves the capacity to do so.  Likewise, when a karmic seed is sown in the alaya consciousness, it will yield fruit when all the right conditions come together. This fruit is also called a karmic effect,  and this particular capacity of the alaya consciousness to yield karmic fruit is the inherent nature of the cause.

After a person has killed a being or stolen things, the karmic seed of such actions will remain in this person’s alaya consciousness. When it will germinate is uncertain, however. The scriptures often used the analogy of harvesting crops to illustrate the timing of karmic effects. There is a wide variety of grains and vegetables and the length of time for them to ripen varies. Some may ripen in only one to two months, and others five or six months, or even longer. The types of seeds, the geographical location, and the climate are all contributing factors to this disparity.    

~ Luminous Wisdom 1 ：On Cause and Effect