How do some plants grow up with water only for the beginning of their life


I often see those timelapse videos of various seed placed in a wet tissue starting to grow roots and then put at the top of a water container, growing quite a lot (like developing leaves and stuff) before being put in an actual pot of dirt.
Where do those plants get the energy and stuff to grow up if all they have is water ? I’ve spent my whole life growing things in dirt directly and it works perfectly, I had no idea you could do water only…

In: 1

plants get their energy from light. they can draw nutrients from the soil, but their main source of energy is the sun. they do photosynthesis to turn light into sugar.

Think of the germination process from a seed as similar to that of an animal born in an egg. Everything that animal needs to go from a single cell, to a baby animal is provided inside the egg itself. Once they hatch though, then it will need food to grow and survive. Similarly all plants need to germinate initially is provided in the seed, they just need water to activate it. So the water from the wet tissue or water container provides that. But just like the baby bird, to continue to grow and thrive after germinating, a plant needs nutrients from the soil.

Plants harness energy from the sun and use it to turn CO2 from the air, plus water from the soil, into sugars, which are used both as a fuel source and as a raw material to build structural compounds like cellulose, lignin (in the case of trees), and starches. So the mass of the plant actually came mostly from the air! Plants need only relatively small amounts of other nutrients from the soil, mainly nitrogen, potassium, and phosphorus. The seed has enough of these to get the plant through its early seedling stage, as well as enough stored up energy for the plant to grow its first leaves, before photosynthesis gets up and running.