Plants have different ways of getting the nutrients they need.
In the beginning, a seed contains all of the nutrients that are needed for it to germinate and grow to the seedling or microgreen stage.
After that, plants need additional nutrients to develop properly.
These nutrients enter through the roots, usually the nutrients come from the soil the plants are grown in.
But, did you know that plants can also be grown without soil? The soil acts as a nutrient storage system, but if you can provide nutrients through the water, the soil is not totally necessary.
If the plants are being grown in soilless media, nutrients will need to be added using a nutrient solution in the water.