"Great news, Mom and Dad—Matt and I are having a cucumber plant! And some peas, and tomatoes, and beets, too. I know we should wait to tell people until we're certain they've germinated, and there's a long way to go before they actually fruit, but we just planted the seeds yesterday and we couldn't be more excited. Matt already built the (raised) beds."
Somehow, I don't think this imaginary conversation with my parents would cause quite as much commotion as a similar announcement my brother and his wife made nine years ago. Theirs was accompanied by a picture of their first daughter's ultrasound. Even though most embryos look pretty similar at that stage, it's always awe-inspiring to see a brand-new person forming in the womb (and I can only imagine the awe is increased a hundredfold if the womb is your own). There is the head with beginnings of eyes, the tiny appendages that will someday turn into limbs with fingers and toes.
What I never realized was that a similar process happens in the plant kingdom. Inside every seed are the basic parts of a fully formed plant: immature roots and tiny leaves curled up like a vegetal embryo. As it turns out, they're even called embryos. Within the seed's protective wall is also a food called endosperm that nourishes the embryonic plant as it starts growing into a seedling.
Friends who have had children in recent years signed up for daily emails telling them what was happening to their fetus at that point in its development. As a novice gardener starting my first vegetable garden, I have a similar curiosity (obviously, on a far less emotional scale) about what's going on just under the surface of my newly planted raised beds. If things are going well, three days after sowing, my little ones should be in the early stages of germination.
I got a preview of how this happens when I tried sprouting radish seeds a couple of months ago. The seeds were soaked in water, then rinsed twice daily to keep them moist. This, plus sufficient warmth, was enough to make the seed coating break down, which released enzymes that caused the embryo to grow into a sprout, or the beginning of a plant—though they wouldn't ever reach full "planthood" without soil and sun.
The same thing is (I hope) happening under the soil with my vegetable seeds, although the required conditions vary slightly for different seeds. Some need warm soil, some need cooler temperatures, and a few require some light to properly germinate (all of which are helpfully spelled out on the seed packets). Larger seeds contain more endosperm, meaning they can be planted deeper into the soil and be nourished as they grow roots and shoots. I enjoyed seeing all the different shapes and sizes of the seeds—beets were knobby and irregular; lettuce, tiny, smooth and lozenge shaped; peas were, well, peas.
This Discovery Channel video explains the germination process in simple terms: After the seed coating breaks apart, the first root, called the radicle, starts to grow downward in search of nutrients. Then another shoot, called a plumule, grows up in search of light. With the help of nutrients from the soil, plus water and light, it will continue to grow to maturity.
The best part of all? No need to save for their college tuition. Although, between seeds and materials and tools, I could see how gardening could become an expensive hobby.