By definition, something is said to be latent when it exists and capable of developing but not yet visible, obvious or active. When you put a grain or seed into the soil, the first few days, weeks, months or even years are period of intense activities (metabolism) within the seed. These activities necessary for germination and growth though not visible to the external environment. That's the latent phase. I'm not a farmer, but am sure the the seedling takes root first before putting forth its shoot and finally starts producing fruits. Note the sequence. Most times, the longer it takes to germinate, the deeper the root. And the deeper the root, the stronger ( and may be longer) the shoot. And most times, the stronger the shoot the longer the life span.